Add: Game UI test:

- Ensures FXML loads and controller initializes without errors.

README.md

@@ -36,7 +36,6 @@ This protocol handles game state synchronization, player actions, lobby and glob
 ├── documents/               # Project resources and documentation
 │   ├── images/              # Images for README and documentation
 │   ├── diary                # Diary files for each organizational meetup
-│   ├── blog                 # Blog files covering project-related topics
 │   ├── docs                 # Documentation
 │   ├── milestones/          # Milestone deliverables (6 milestones)
 │   └── (Other resources)    # Additional project materials

build.gradle

@@ -4,6 +4,7 @@ plugins {
     id 'org.openjfx.javafxplugin' version '0.1.0'
     id 'checkstyle'
     id 'com.diffplug.spotless' version '7.0.2'
+    id 'jacoco'
 }
 
 group = 'ch.unibas.dmi.dbis'
@@ -32,7 +33,7 @@ dependencies {
     // Source: https://mvnrepository.com/artifact/org.apache.logging.log4j
     implementation("org.apache.logging.log4j:log4j-api:2.25.3")
     runtimeOnly("org.apache.logging.log4j:log4j-core:2.25.3")
-
+    implementation("org.jspecify:jspecify:1.0.0")
     // Source: https://mvnrepository.com/artifact/org.fusesource.jansi/jansi
     runtimeOnly("org.fusesource.jansi:jansi:2.4.2")
 
@@ -41,8 +42,17 @@ dependencies {
     implementation 'org.json:json:20240303'
 }
 
+jacoco {
+    toolVersion = "0.8.14"
+}
+
+jacocoTestReport {
+    dependsOn test
+}
+
 test {
     useJUnitPlatform()
+    finalizedBy jacocoTestReport
 }
 
 checkstyle {

config/checkstyle/suppressions.xml

@@ -21,4 +21,7 @@
 
     <!-- Allow for compacter line seperators -->
     <suppress checks="EmptyLineSeparator" files=".*Test\.java"/>
+
+    <!-- Allow longer method length in composition root -->
+    <suppress checks="MethodLength" files="ServerApp.java"/>
 </suppressions>

documents/blog/README.md

@@ -1,28 +0,0 @@
-# Blog
-
-## Purpose
-This folder contains a collection of blog posts documenting the development process of our application. These blogs serve two key purposes:
-
-1. **For External Audiences**
-
-    The blogs provide insights into the internal program flow and the interaction between components without requiring readers to dive into the source code. They offer a mixed-level overview of how different parts of the system work together.
-
-2. **For Our Team**
-
-    The blogs serve as a record of our decision-making process. By documenting what decisions were made and why, we can track the evolution of our design choices and understand the reasoning behind them. This is invaluable for maintaining consistency across the team.
-
-But keep in mind that these blogs **do not replace** the detailed source code documentation.
-
-## Format
-All blog posts follow the naming convention: `<YYYY-MM-DD>_<Title>.md`
-
-## Blog Posts
-
-### General
-*(No posts yet)*
-
-### Client
-*(No posts yet)*
-
-### Server
-*(No posts yet)*

documents/diary/09-04.md

@@ -0,0 +1,9 @@
+# Besprechung über Veränderung der Aufgabenteilung
+
+## Verschieben von Aufgaben
+
+Da die Implementation der client server Kommunikation länger dauerte als geplant, wurden achivements erfüllt, die erst bei späteren Meilensteinen relevant sein werden.
+
+## Aufgabeverteilung
+
+Um zu vermeiden, dass sich Personen erst lange Zeit in den Code anderer einarbeiten müssen um zu helfen, wurden Dokumentation und das Erstellen von Materialien für MS4 auf ein Teammitgleid (Jona) ausgelagert um das Projekt nicht zu verlangsamen

documents/diary/10-04.md

@@ -0,0 +1,38 @@
+# Neue Aufgabenteilung für MS4 (10.04)
+
+## Kurzfassung
+
+Offene Meilensteine wurden überprüft und Personen zugewiesen. Ziel ist, verbleibende Funktionen (Game List, Username-Integration, Lobby/Chat-Funktionen) bis zum nächsten Sprint stabil zu machen.
+
+## Offene Aufgaben
+
+- Broadcast: Offen (Priorität niedrig)
+- Username-Integration: In Backend integrieren und frontend Anpasungen (wichtig)
+- Demo: Kernfunktion vorhanden, muss getestet werden
+- Game List: Backend fehlt vollständig
+- Chat: Globaler Chat und Lobby-Chat müssen eingebunden werden
+- Lounging: Support für mehrere Lobbys und Spielerlisten
+- QA: Präsentation und Dokumentation
+- Rules to Code: Vorstellung und Integration
+- "Shall we play a game": Flag zum Umschalten zwischen Demo- und Normalmodus
+- Whisper: Funktion (siehe Zuordnung)
+- Zeitplan: Verschiebung von nicht-kritischen Punkten
+
+## Aufgaben & Zustänextrdigkeiten
+
+- Jona
+ 	- Command Line: Parsing, Option für Username-Eingabe (Start vs. Lobby)
+ 	- Game List: Implementierung (Datenstruktur, Commands, Backend-Anbindung)
+ 	- Lounging: Mehrere Lobbys, Liste aller Spieler
+
+- Lars
+ 	- QA: Präsentation und ausgeschriebenes Dokument
+
+- Mathis
+ 	- Whisper-Chat: Fertigstellung
+ 	- Lobby-Chat: Integration
+
+- Julian
+ 	- Game Engine: Fertigstellung
+ 	- Flag: Umschalten zwischen Demo- und echter Game Engine
+ 	- Rules to Code: Vorstellung

documents/diary/README.md

@@ -1,7 +1,7 @@
 # Meeting Diary
 
 This folder holds the notes and documentation of all team meetings throughout the project.
-The notes are organised by **milestones (1–6)** so that everyone can easily see what was discussed and decided at each stage. Each sub-header below links to the actual Markdown file containing the details.
+The notes are organized by **milestones (1–6)** so that everyone can easily see what was discussed and decided at each stage. Each sub-header below links to the actual Markdown file containing the details.
 
 ## Milestone 1
 ### [24. February 2026](24-02.md)
@@ -14,19 +14,28 @@ The notes are organised by **milestones (1–6)** so that everyone can easily se
 - Finalizing structure of network protocol
 
 
-## Milestone 2
-*(Meeting notes to be added here when available)*
+## Milestone 2
+### [14. March 2025](14-03.md)
+- Discussion of LobbyScreen, GameScreen, and Chatbox structure
+- Endscreen postponed to MS3
 
 
-## Milestone 3
-*(Meeting notes to be added here when available)*
+## Milestone 3
+None, as milestone 3 covered the assessment of individual technical understanding through evaluation.
 
 
-## Milestone 4
-*(Meeting notes to be added here when available)*
+## Milestone 4
+### [09. April 2026](09-04.md)
+- Task redistribution due to delays in client-server communication
+- Documentation and MS4 materials assigned to Jona
+
+### [10. April 2026](10-04.md)
+- Review and assignment of open milestones
+- Focus on stabilizing Game List, Username-Integration, Lobby/Chat functions
+- Task list for remaining features and QA
 
 
-## Milestone 5
+## Milestone 5
 *(Meeting notes to be added here when available)*
 
 

documents/docs/game-engine/README.md

@@ -4,3 +4,4 @@
 - [Game Engine Architecture](game-engine-architecture.md)
 - [Casono Rules Easy Description](casono-rules-easy-description.md)
 - [Game engine implementation](game-engine-implementation.md)
+- [Casonso Manual](casono-manual.md)

documents/docs/game-engine/casono-manual.md

@@ -0,0 +1,162 @@
+# Casono Manual
+
+> Hinweis: Eine vereinfachte Einführung finden Sie in der Datei [Casono Rules – Easy Description](casono-rules-easy-description.md).
+> Dieses Dokument beschreibt den Ablauf eines Pokerspiels anhand eines Beispiels.
+<!-- vim-markdown-toc GFM -->
+
+* [1. Spielübersicht](#1-spielübersicht)
+    * [Grundregeln](#grundregeln)
+* [2. Sitzposition & Dealer-Button](#2-sitzposition--dealer-button)
+* [3. Blinds (Pflichteinsätze)](#3-blinds-pflichteinsätze)
+* [4. Spielablauf im Detail](#4-spielablauf-im-detail)
+    * [4.1 Preflop (erste Setzrunde)](#41-preflop-erste-setzrunde)
+    * [4.2 Flop (3 Gemeinschaftskarten)](#42-flop-3-gemeinschaftskarten)
+    * [4.3 Turn (4. Gemeinschaftskarte)](#43-turn-4-gemeinschaftskarte)
+    * [4.4 River (5. Gemeinschaftskarte)](#44-river-5-gemeinschaftskarte)
+* [5. Showdown (Kartenvergleich)](#5-showdown-kartenvergleich)
+* [6. Poker-Handrangfolge](#6-poker-handrangfolge)
+* [7. Wichtige Grundprinzipien](#7-wichtige-grundprinzipien)
+    * [Reihenfolge beachten](#reihenfolge-beachten)
+    * [Klare Aktionen](#klare-aktionen)
+    * [Ein Spieler – eine Hand](#ein-spieler--eine-hand)
+    * [Fehlerhafte Einsätze](#fehlerhafte-einsätze)
+* [8. Strategische Einordnung](#8-strategische-einordnung)
+
+<!-- vim-markdown-toc -->
+
+## 1. Spielübersicht
+
+Texas Hold’em ist ein strategisches Kartenspiel für mehrere Spieler. 
+Ziel ist es, den Pot (alle gesetzten Chips) zu gewinnen, entweder durch:
+
+- die beste Kartenkombination am Ende der Runde
+- oder indem alle anderen Spieler vorher aussteigen (Fold)
+
+### Grundregeln
+
+- Jeder Spieler erhält 2 verdeckte Karten (Hole Cards)
+- Es werden 5 Gemeinschaftskarten offen in der Mitte ausgelegt
+- Jeder Spieler bildet die beste 5-Karten-Kombination aus:
+  - eigenen Karten
+  - und Gemeinschaftskarten
+
+- Zu Spielbeginn erhält jeder Spieler ein Startgeld von 20000 Chips ($)
+
+## 2. Sitzposition & Dealer-Button
+
+Der sogenannte Dealer-Button bestimmt die Positionen am Tisch:
+
+- Er zeigt an, wer als „Geber“ (Dealer) fungiert
+- Die Positionen rotieren im Uhrzeigersinn nach jeder Runde
+
+Die Position ist entscheidend, da sie bestimmt:
+
+- die Reihenfolge der Aktionen
+- wer die Blinds setzen muss
+
+## 3. Blinds (Pflichteinsätze)
+
+Vor jeder Runde werden zwei verpflichtende Einsätze geleistet:
+
+- **Small Blind** (kleiner Blind): 100 Chips – gesetzt vom Spieler links neben dem Dealer
+- **Big Blind** (großer Blind): 200 Chips - gesetzt vom Spieler zwei Plätze links vom Dealer
+
+Diese Einsätze sorgen dafür, dass:
+
+- ein Startpot entsteht
+- jede Runde aktiv gespielt wird
+
+## 4. Spielablauf im Detail
+
+### 4.1 Preflop (erste Setzrunde)
+
+Nach dem Austeilen der Karten beginnt die erste Setzrunde.
+
+Der Spieler links vom Big Blind eröffnet die Runde.
+
+Jeder Spieler hat folgende Optionen:
+
+- **Fold** – Karten ablegen und aussteigen
+- **Call** – Einsatz mitgehen
+- **Raise** – Einsatz erhöhen
+
+### 4.2 Flop (3 Gemeinschaftskarten)
+
+- Drei Karten werden offen auf den Tisch gelegt
+- Eine neue Setzrunde beginnt
+- Die Setzrunde beginnt jetzt immer beim ersten aktiven Spieler links vom Dealer (im Uhrzeigersinn).
+
+Ab diesem Zeitpunkt können alle Spieler ihre Strategie anhand zusätzlicher Informationen anpassen.
+
+### 4.3 Turn (4. Gemeinschaftskarte)
+
+- Die vierte Karte wird aufgedeckt
+- Eine weitere Setzrunde folgt
+
+Die Einsätze werden oft höher, da sich stärkere Hände entwickeln.
+
+### 4.4 River (5. Gemeinschaftskarte)
+
+- Die letzte Karte wird aufgedeckt
+- Letzte Setzrunde
+
+Dies ist die finale Entscheidungsphase:
+
+- Maximierung des Gewinns
+- oder Minimierung von Verlusten
+
+## 5. Showdown (Kartenvergleich)
+
+Wenn nach der letzten Setzrunde mindestens zwei Spieler verbleiben:
+
+- Alle verbleibenden Spieler decken ihre Karten auf
+- Die **beste 5-Karten-Kombination gewinnt**
+
+Wichtig:
+
+- Die Karten „sprechen für sich“ – die beste Hand zählt unabhängig von Ansagen
+
+## 6. Poker-Handrangfolge
+
+Die Stärke der Hände ist eindeutig festgelegt (von schwach nach stark):
+
+1. High Card (höchste Einzelkarte)
+2. One Pair (ein Paar)
+3. Two Pair (zwei Paare)
+4. Three of a Kind (Drilling)
+5. Straight (Straße)
+6. Flush (Farbe)
+7. Full House
+8. Four of a Kind (Vierling)
+9. Straight Flush
+10. Royal Flush
+
+Je höher die Kombination, desto stärker die Hand.
+
+## 7. Wichtige Grundprinzipien
+
+### Reihenfolge beachten
+
+Spieler müssen immer der Reihe nach handeln.
+
+### Klare Aktionen
+
+Alle Aktionen müssen eindeutig sein:
+
+- Einsätze klar ansagen oder eindeutig setzen
+
+### Ein Spieler – eine Hand
+
+- Spieler dürfen ihre Karten nicht teilen oder gemeinsam spielen
+
+### Fehlerhafte Einsätze
+
+- Unklare oder falsche Einsätze können korrigiert werden, abhängig von der Spielsituation (nur wenn der Einsatz außerhalb der gültigen Grenzen liegt; zu hohe oder unzulässige Beträge werden blockiert und nicht automatisch korrigiert)
+
+## 8. Strategische Einordnung
+
+Texas Hold’em ist kein reines Glücksspiel. Der Erfolg basiert auf:
+
+- Wahrscheinlichkeiten (Mathematik)
+- Einschätzung von Gegnern (Psychologie)
+- Positionsspiel und Timing

documents/docs/game-engine/casono-markdown-render-engine.js

@@ -0,0 +1,84 @@
+const marked = {
+    parse: function (md) {
+        if (!md) return "";
+
+        let toc = [];
+
+        md = md.replace(/^(#{1,3})\s+(.*)$/gim, (m, hashes, title) => {
+            const level = hashes.length;
+
+            const id = title
+                .toLowerCase()
+                .trim()
+                .replace(/[^\wäöüß]+/g, "-")
+                .replace(/-+/g, "-")
+                .replace(/^-|-$/g, "");
+
+            toc.push({ level, title, id });
+
+            return `
+                <h${level} id="${id}" class="cm-h${level}">
+                    ${title}
+                </h${level}>
+            `;
+        });
+
+        md = md.replace(/```([\s\S]*?)```/g, (_, code) => {
+            return `<pre class="cm-code"><code>${escapeHtml(code)}</code></pre>`;
+        });
+
+        md = md.replace(/!\[(.*?)\]\((.*?)\)/gim,
+            `<img alt="$1" src="$2" class="cm-img">`
+        );
+
+        md = md.replace(/\[(.*?)\]\((.*?)\)/gim,
+            `<a href="$2" target="_blank" class="cm-link">$1</a>`
+        );
+
+        md = md.replace(/`(.*?)`/gim,
+            `<code class="cm-inline">$1</code>`
+        );
+
+        md = md.replace(/\*\*(.*?)\*\*/gim, "<b>$1</b>");
+        md = md.replace(/\*(.*?)\*/gim, "<i>$1</i>");
+
+        md = md.replace(/^\s*-\s(.+)$/gim, "<li>$1</li>");
+        md = wrapLists(md);
+
+        md = md
+            .replace(/\n{2,}/g, "</p><p>")
+            .replace(/^(?!<h|<ul|<pre|<li|<\/)(.+)$/gim, "<p>$1</p>");
+
+        return buildToc(toc) + md;
+    }
+};
+
+function buildToc(items) {
+    if (!items.length) return "";
+
+    let html = `<div class="cm-toc">`;
+
+    items.forEach(i => {
+        html += `
+            <div class="cm-toc-item level-${i.level}">
+                <a href="#${i.id}">${i.title}</a>
+            </div>
+        `;
+    });
+
+    html += `</div>`;
+    return html;
+}
+
+function wrapLists(html) {
+    return html.replace(/(<li>.*?<\/li>)/gs, "<ul>$1</ul>");
+}
+
+function escapeHtml(text) {
+    return text
+        .replace(/&/g, "&amp;")
+        .replace(/</g, "&lt;")
+        .replace(/>/g, "&gt;");
+}
+
+window.marked = marked;

documents/docs/game-engine/casono-rules-easy-description.md

@@ -1,56 +1,42 @@
 # Casono Rules Easy Description
 
-> Source: https://www.youtube.com/watch?v=h-1WyU5Wqsw&pp=ygUZbGVybmVuIHBva2VyIHRleGFzIGhvbGRlbQ%3D%3D
+> Quelle: https://www.youtube.com/watch?v=h-1WyU5Wqsw&pp=ygUZbGVybmVuIHBva2VyIHRleGFzIGhvbGRlbQ%3D%3D
 <!-- vim-markdown-toc GFM -->
 
-* [Deustch](#deustch)
-    * [Blinds (Small Blind & Big Blind)](#blinds-small-blind--big-blind)
-    * [Erste Setzrunde (Preflop)](#erste-setzrunde-preflop)
-    * [Beispiel Preflop](#beispiel-preflop)
-    * [Flop (3 Gemeinschaftskarten)](#flop-3-gemeinschaftskarten)
-    * [Beispiel Flop](#beispiel-flop)
-    * [Turn (4. Karte)](#turn-4-karte)
-    * [River (5. Karte)](#river-5-karte)
-    * [Showdown (Gewinnentscheidung)](#showdown-gewinnentscheidung)
-    * [Poker Hand Rankings (Gewichtung)](#poker-hand-rankings-gewichtung)
-    * [Fazit](#fazit)
-* [English](#english)
-    * [Blinds (Small Blind & Big Blind)](#blinds-small-blind--big-blind-1)
-    * [First Betting Round (Preflop)](#first-betting-round-preflop)
-    * [Preflop Example](#preflop-example)
-    * [Flop (3 Community Cards)](#flop-3-community-cards)
-    * [Flop Example](#flop-example)
-    * [Turn (4th Card)](#turn-4th-card)
-    * [River (5th Card)](#river-5th-card)
-    * [Showdown (Winning Decision)](#showdown-winning-decision)
-    * [Poker Hand Rankings (Hierarchy)](#poker-hand-rankings-hierarchy)
-    * [Conclusion](#conclusion)
+* [Blinds (Small Blind & Big Blind)](#blinds-small-blind--big-blind)
+* [Erste Setzrunde (Preflop)](#erste-setzrunde-preflop)
+* [Beispiel Preflop](#beispiel-preflop)
+* [Flop (3 Gemeinschaftskarten)](#flop-3-gemeinschaftskarten)
+* [Beispiel Flop](#beispiel-flop)
+* [Turn (4. Karte)](#turn-4-karte)
+* [River (5. Karte)](#river-5-karte)
+* [Showdown (Gewinnentscheidung)](#showdown-gewinnentscheidung)
+* [Poker Hand Rankings (Gewichtung)](#poker-hand-rankings-gewichtung)
+* [Fazit](#fazit)
 
 <!-- vim-markdown-toc -->
 
-## Deutsch
-
-Der Pokertisch ist ein unglaublich faszinierender Erlebnisraum, in dem man sehr viel lernen kann: über sich selbst, über andere Menschen und über Fragen wie: wie treffe ich eigentlich Entscheidungen, wie gehe ich mit Stress und Unsicherheit um und wie gut ich darin bin, mich in andere hineinzuversetzen und Situationen richtig einzuschätzen.
+Der Pokertisch ist ein unglaublich faszinierender Erlebnisraum, in dem man sehr viel lernen kann: über sich selbst, über andere Menschen und über Fragen wie: Wie treffe ich eigentlich Entscheidungen, wie gehe ich mit Stress und Unsicherheit um und wie gut ich darin bin, mich in andere hineinzuversetzen und Situationen richtig einzuschätzen.
 
 Damit Du in diesem Erlebnisraum starten kannst, ist es – wie bei jedem Spiel – notwendig, zuerst die Grundregeln und den Spielablauf zu verstehen.
 
 Also los geht es:
 
-Wir haben am Tisch **4 Spieler**: Julian, Mathis, Jona und Lars. Jeder Spieler startet mit **20.000 Chips**. Jeder bekommt **2 Karten auf die Hand** und es gibt zusätzlich **5 Gemeinschaftskarten**, die später in der Mitte aufgedeckt werden.
+Wir haben am Tisch **4 Spieler**: Julian, Mathis, Jona und Lars. Jeder Spieler startet mit **20000 Chips ($)**. Jeder bekommt **2 Karten auf die Hand** und es gibt zusätzlich **5 Gemeinschaftskarten**, die später in der Mitte aufgedeckt werden.
 
-![1. image](./images/1.png)
+![1. image](./images/1-1.svg)
 
 Die Spieler sitzen in folgender Reihenfolge: Julian, Mathis, Jona und Lars. Einer davon hat den Dealer-Button, der bestimmt, wer die Karten austeilt und von wo die Runde beginnt. Dieser Button wandert nach jeder Runde im Uhrzeigersinn weiter und verändert damit die Position ständig.
 
 Regel: *34 Button Placement and Movement 🟢*
 
-### Blinds (Small Blind & Big Blind)
+## Blinds (Small Blind & Big Blind)
 
 Bevor die Karten verteilt werden, gibt es zwei Pflicht-Einsätze:
 
 Der Small Blind und der Big Blind. Der Big Blind ist immer doppelt so hoch wie der Small Blind.
 
-![2. image](./images/2.png)
+![2. image](./images/2-1.svg)
 
 Regel: *32 Dead Button 🟡*
 
@@ -58,7 +44,7 @@ Diese Einsätze sorgen dafür, dass sofort ein Pot entsteht und das Spiel überh
 
 Danach werden die Karten verteilt: zuerst Small Blind, dann Big Blind und dann im Uhrzeigersinn alle anderen Spieler.
 
-### Erste Setzrunde (Preflop)
+## Erste Setzrunde (Preflop)
 
 Die erste Setzrunde beginnt immer bei dem Spieler links vom Big Blind.
 
@@ -73,251 +59,108 @@ Regel: *41 Methods of Calling 🟢*
 Regel: *42 Methods of Raising 🟢*
 Regel: *50 Acting in Turn 🟢*
 
-### Beispiel Preflop
+## Beispiel Preflop
 
-Julian schaut seine Karten an und entscheidet sich direkt für einen Call von **600 Chips**.
+Julian schaut seine Karten an und entscheidet sich direkt für einen Raise von **600 Chips**.
 
-![3. image](./images/3.png)
+![3. image](./images/3-1.svg)
 
 Mathis sieht seine Karten an und merkt, dass sie nicht gut sind, also foldet er und steigt aus.
 
-![4. image](./images/4.png)
+![4. image](./images/4-1.svg)
 
 Jona ist nun dran und entscheidet sich ebenfalls für einen Call, weil seine Hand spielbar ist.
 
-![5. image](./images/5.png)
+![5. image](./images/5-1.svg)
 
 Lars schaut seine Karten an, erkennt eine starke Hand und erhöht auf **1200 Chips**.
 
-![6. image](./images/6.png)
+![6. image](./images/6-1.svg)
 
 Damit verändert sich sofort die Situation: Julian und Jona müssen entscheiden, ob sie diesen Raise bezahlen, selbst erhöhen oder aussteigen.
 
-### Flop (3 Gemeinschaftskarten)
+## Flop (3 Gemeinschaftskarten)
 
 Jetzt werden **3 Gemeinschaftskarten** in die Mitte gelegt. Ab hier verändert sich das Spiel komplett, weil alle Spieler zusätzliche Informationen bekommen.
 
-![7. image](./images/7.png)
+Die Setzrunde beginnt jetzt immer beim ersten aktiven Spieler links vom Dealer (im Uhrzeigersinn).
+
+![7. image](./images/7-1.svg)
 
 Es beginnt eine neue Setzrunde.
 
 Regel: *49 Accepted Action 🟢*
 
-### Beispiel Flop
+## Beispiel Flop
 
-Lars setzt **1000 Chips** als Erstes. Julian entscheidet sich mitzugehen (Call), weil seine Karten durch die Gemeinschaftskarten stärker geworden sind.
+Jona setzt **1000 Chips** als Erstes. Lars entscheidet sich mitzugehen (Call), weil seine Karten durch die Gemeinschaftskarten stärker geworden sind.
 
-![8. image](./images/8.png)
+Julian steigt aus, weil er keine gute Verbindung mehr sieht. Mathis ist bereits raus.
 
-Jona steigt aus, weil er keine gute Verbindung mehr sieht. Mathis ist bereits raus.
+![8. image](./images/8-1.svg)
 
-### Turn (4. Karte)
+## Turn (4. Karte)
 
 Jetzt kommt die **4. Gemeinschaftskarte**.
 
 Wieder beginnt eine neue Setzrunde.
 
-Lars setzt diesmal **3000 Chips**. Julian bezahlt erneut (Call), weil seine Hand weiterhin gut spielbar ist.
+Jona setzt diesmal **3000 Chips**. Lars bezahlt erneut (Call), weil seine Hand weiterhin gut spielbar ist.
 
-![9. image](./images/9.png)
+![9. image](./images/9-1.png)
 
 Regel: *53 Action Out of Turn 🟡*
 
-### River (5. Karte)
+## River (5. Karte)
 
 Jetzt wird die letzte Gemeinschaftskarte aufgedeckt.
 
 Dies ist die letzte Entscheidung im Spiel.
 
-Lars setzt **5000 Chips**.
+Jona setzt **5000 Chips**.
 
-![10. image](./images/10.png)
+![10. image](./images/10-1.png)
 
-Julian muss jetzt entscheiden: Fold, Call oder Raise auf **10000 Chips**.
+Lars muss jetzt entscheiden: Fold, Call oder Raise auf 10000 Chips.
 
 Regel: *54 Pot Size Bets 🟡*
 
-### Showdown (Gewinnentscheidung)
+## Showdown (Gewinnentscheidung)
 
 Wenn nach der letzten Setzrunde noch zwei Spieler übrig sind, kommt es zum Showdown.
 
 Beide Spieler zeigen ihre Karten offen. Gewonnen hat die **beste 5-Karten-Kombination aus Handkarten und Gemeinschaftskarten**.
 
-![11. image](./images/11.png)
+![11. image](./images/11-1.png)
 
 Regel: *12 Cards Speak at Showdown 🟢*
 Regel: *16 Face Up for All-Ins 🟢*
 Regel: *17 Non All-In Showdowns 🟢*
 
-Wenn Julian den letzten Einsatz bezahlt, werden die Hände verglichen. Wenn er foldet, gewinnt Lars automatisch den gesamten Pot.
+Wenn Lars den letzten Einsatz bezahlt, werden die Hände verglichen. Wenn er foldet, gewinnt Jona automatisch den gesamten Pot.
 
-### Poker Hand Rankings (Gewichtung)
+## Poker Hand Rankings (Gewichtung)
 
 Die Kartenkombinationen sind klar geordnet – von schwach bis extrem stark:
 
-![12. image](./images/12.png)
+<img src="./images/12.png" height="600">
 
 Je höher die Kombination, desto stärker die Hand und desto wahrscheinlicher der Gewinn.
 
-Julian: 2. Paar: 
+Jona: 2. Paar: 
 
-![13. image](./images/13.png)
+![13. image](./images/13-1.png)
 
 Lars: 1. Paar:
 
-![14. image](./images/14.png)
+![14. image](./images/14-1.png)
 
-Da zwei Paare in der Rangfolge über einem einzelnen Paar stehen, gewinnt Julian diese Runde.
+Da zwei Paare in der Rangfolge über einem einzelnen Paar stehen, gewinnt Jona diese Runde.
 
-### Fazit
+## Fazit
 
 Poker ist kein Glücksspiel im klassischen Sinn, sondern ein Spiel aus Strategie, Psychologie und Mathematik. Jede Entscheidung von Julian, Mathis, Jona oder Lars verändert die komplette Dynamik am Tisch. Wer die Regeln versteht, versteht nicht nur Karten, sondern auch Menschen und Entscheidungen unter Druck.
 
 Regel: *67 One Player One Hand 🟢*
 Regel: *52 Incorrect Bets 🟡*
 Regel: *57 Non-Standard Betting 🟡*
-
-## English
-
-The poker table is an incredibly fascinating experiential space where you can learn a great deal: about yourself, about other people, and about questions such as: How do I actually make decisions? How do I handle stress and uncertainty? And how good am I at empathizing with others and correctly assessing situations?
-
-To enter this experiential space, it’s necessary—like with any game—to first understand the basic rules and game flow.
-
-So let’s begin:
-
-We have **4 players** at the table: Julian, Mathis, Jona, and Lars. Each player starts with **20,000 chips**. Each receives **2 hole cards**, and there are **5 community cards** that will later be revealed in the center.
-
-![1. image](./images/1.png)
-
-The players are seated as follows: Julian, Mathis, Jona, and Lars. One of them holds the dealer button, which determines who deals the cards and where the round begins. This button moves clockwise after each hand, constantly changing the positions.
-
-Rule: *34 Button Placement and Movement 🟢*
-
-### Blinds (Small Blind & Big Blind)
-
-Before cards are dealt, there are two mandatory bets:
-
-The Small Blind and the Big Blind. The Big Blind is always double the amount of the Small Blind.
-
-![2. image](./images/2.png)
-
-Rule: *32 Dead Button 🟡*
-
-These forced bets ensure that a pot exists from the start, making the game begin with everyone already involved.
-
-After this, the cards are dealt: first to the Small Blind, then the Big Blind, and then clockwise to all other players.
-
-### First Betting Round (Preflop)
-
-The first betting round always begins with the player to the left of the Big Blind.
-
-Now each player must decide:
-
-* Fold (exit the hand)
-* Call (match the current bet)
-* Raise (increase the bet)
-
-Rule: *40 Methods of Betting 🟢*  
-Rule: *41 Methods of Calling 🟢*  
-Rule: *42 Methods of Raising 🟢*  
-Rule: *50 Acting in Turn 🟢*
-
-### Preflop Example
-
-Julian looks at his cards and decides to Call for **600 chips**.
-
-![3. image](./images/3.png)
-
-Mathis sees his cards and realizes they aren’t strong, so he Folds and exits the hand.
-
-![4. image](./images/4.png)
-
-Jona is next and decides to Call as well, because his hand is playable.
-
-![5. image](./images/5.png)
-
-Lars looks at his cards, recognizes a strong hand, and Raises to **1200 chips**.
-
-![6. image](./images/6.png)
-
-This immediately changes the situation: Julian and Jona must now decide whether to call this raise, re-raise, or fold.
-
-### Flop (3 Community Cards)
-
-Now **3 community cards** are placed face-up in the center. From this point, the game changes completely, as all players gain additional information.
-
-![7. image](./images/7.png)
-
-A new betting round begins.
-
-Rule: *49 Accepted Action 🟢*
-
-### Flop Example
-
-Lars bets **1,000 chips** first. Julian decides to Call because his hand has improved with the community cards.
-
-![8. image](./images/8.png)
-
-Jona folds, as he no longer sees a strong connection. Mathis is already out.
-
-### Turn (4th Card)
-
-Now the **4th community card** is revealed.
-
-Another betting round begins.
-
-Lars bets **3,000 chips** this time. Julian calls again, as his hand remains strong.
-
-![9. image](./images/9.png)
-
-Rule: *53 Action Out of Turn 🟡*
-
-### River (5th Card)
-
-Now the final community card is revealed.
-
-This is the last decision point in the hand.
-
-Lars bets **5,000 chips**.
-
-![10. image](./images/10.png)
-
-Julian must now decide: Fold, Call, or even Raise to **10,000 chips**.
-
-Rule: *54 Pot Size Bets 🟡*
-
-### Showdown (Winning Decision)
-
-If two or more players remain after the final betting round, a showdown occurs.
-
-All active players reveal their cards. The winner is the one with the **best 5-card combination using any combination of their hole cards and the community cards**.
-
-![11. image](./images/11.png)
-
-Rule: *12 Cards Speak at Showdown 🟢*  
-Rule: *16 Face Up for All-Ins 🟢*  
-Rule: *17 Non All-In Showdowns 🟢*
-
-If Julian calls the final bet, the hands are compared. If he folds, Lars wins the entire pot automatically.
-
-### Poker Hand Rankings (Hierarchy)
-
-The card combinations are clearly ranked—from weakest to strongest:
-
-![12. image](./images/12.png)
-
-The higher the combination, the stronger the hand, and the greater the chance of winning.
-
-Julian: Two Pair:
-
-![13. image](./images/13.png)
-
-Lars: One Pair:
-
-![14. image](./images/14.png)
-
-Since two pair ranks higher than one pair, Julian wins this round.
-
-### Conclusion
-
-Poker is not gambling in the traditional sense, but rather a game of strategy, psychology, and mathematics. Every decision made by Julian, Mathis, Jona, or Lars changes the entire dynamic at the table. Understanding the rules means not only understanding cards, but also people and decision-making under pressure.

documents/docs/game-engine/manual.html

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+<html lang="en">
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+        /* CODE */
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+            background: rgba(0,0,0,0.4);
+            padding: 2px 5px;
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+    </style>
+</head>
+
+<body>
+
+<div id="content"></div>
+
+<script>
+
+    window.addEventListener("DOMContentLoaded", () => {
+        const markdown = `
+# Casono Manual
+
+Hinweis: Eine vereinfachte Einführung finden Sie in der Datei [Casono Rules – Easy Description](casono-rules-easy-description.md).
+Dieses Dokument beschreibt den Ablauf eines Pokerspiels anhand eines Beispiels.
+
+## 1. Spielübersicht
+
+Texas Hold’em ist ein strategisches Kartenspiel für mehrere Spieler.
+Ziel ist es, den Pot (alle gesetzten Chips) zu gewinnen, entweder durch:
+
+- die beste Kartenkombination am Ende der Runde
+- oder indem alle anderen Spieler vorher aussteigen (Fold)
+
+### Grundregeln
+
+- Jeder Spieler erhält 2 verdeckte Karten (Hole Cards)
+- Es werden 5 Gemeinschaftskarten offen in der Mitte ausgelegt
+- Jeder Spieler bildet die beste 5-Karten-Kombination aus:
+  - eigenen Karten
+  - und Gemeinschaftskarten
+
+- Zu Spielbeginn erhält jeder Spieler ein Startgeld von 20000 Chips ($)
+
+## 2. Sitzposition & Dealer-Button
+
+Der sogenannte Dealer-Button bestimmt die Positionen am Tisch:
+
+- Er zeigt an, wer als „Geber“ (Dealer) fungiert
+- Die Positionen rotieren im Uhrzeigersinn nach jeder Runde
+
+Die Position ist entscheidend, da sie bestimmt:
+
+- die Reihenfolge der Aktionen
+- wer die Blinds setzen muss
+
+## 3. Blinds (Pflichteinsätze)
+
+Vor jeder Runde werden zwei verpflichtende Einsätze geleistet:
+
+- **Small Blind** (kleiner Blind): 100 Chips – gesetzt vom Spieler links neben dem Dealer
+- **Big Blind** (großer Blind): 200 Chips - gesetzt vom Spieler zwei Plätze links vom Dealer
+
+Diese Einsätze sorgen dafür, dass:
+
+- ein Startpot entsteht
+- jede Runde aktiv gespielt wird
+
+## 4. Spielablauf im Detail
+
+### 4.1 Preflop (erste Setzrunde)
+
+Nach dem Austeilen der Karten beginnt die erste Setzrunde.
+
+Der Spieler links vom Big Blind eröffnet die Runde.
+
+Jeder Spieler hat folgende Optionen:
+
+- **Fold** – Karten ablegen und aussteigen
+- **Call** – Einsatz mitgehen
+- **Raise** – Einsatz erhöhen
+
+### 4.2 Flop (3 Gemeinschaftskarten)
+
+- Drei Karten werden offen auf den Tisch gelegt
+- Eine neue Setzrunde beginnt
+- Die Setzrunde beginnt jetzt immer beim ersten aktiven Spieler links vom Dealer (im Uhrzeigersinn).
+
+Ab diesem Zeitpunkt können alle Spieler ihre Strategie anhand zusätzlicher Informationen anpassen.
+
+### 4.3 Turn (4. Gemeinschaftskarte)
+
+- Die vierte Karte wird aufgedeckt
+- Eine weitere Setzrunde folgt
+
+Die Einsätze werden oft höher, da sich stärkere Hände entwickeln.
+
+### 4.4 River (5. Gemeinschaftskarte)
+
+- Die letzte Karte wird aufgedeckt
+- Letzte Setzrunde
+
+Dies ist die finale Entscheidungsphase:
+
+- Maximierung des Gewinns
+- oder Minimierung von Verlusten
+
+## 5. Showdown (Kartenvergleich)
+
+Wenn nach der letzten Setzrunde mindestens zwei Spieler verbleiben:
+
+- Alle verbleibenden Spieler decken ihre Karten auf
+- Die **beste 5-Karten-Kombination gewinnt**
+
+Wichtig:
+
+- Die Karten „sprechen für sich“ – die beste Hand zählt unabhängig von Ansagen
+
+## 6. Poker-Handrangfolge
+
+Die Stärke der Hände ist eindeutig festgelegt (von schwach nach stark):
+
+1. High Card (höchste Einzelkarte)
+2. One Pair (ein Paar)
+3. Two Pair (zwei Paare)
+4. Three of a Kind (Drilling)
+5. Straight (Straße)
+6. Flush (Farbe)
+7. Full House
+8. Four of a Kind (Vierling)
+9. Straight Flush
+10. Royal Flush
+
+Je höher die Kombination, desto stärker die Hand.
+
+## 7. Wichtige Grundprinzipien
+
+### Reihenfolge beachten
+
+Spieler müssen immer der Reihe nach handeln.
+
+### Klare Aktionen
+
+Alle Aktionen müssen eindeutig sein:
+
+- Einsätze klar ansagen oder eindeutig setzen
+
+### Ein Spieler – eine Hand
+
+- Spieler dürfen ihre Karten nicht teilen oder gemeinsam spielen
+
+### Fehlerhafte Einsätze
+
+- Unklare oder falsche Einsätze können korrigiert werden, abhängig von der Spielsituation (nur wenn der Einsatz außerhalb der gültigen Grenzen liegt; zu hohe oder unzulässige Beträge werden blockiert und nicht automatisch korrigiert)
+
+## 8. Strategische Einordnung
+
+Texas Hold’em ist kein reines Glücksspiel. Der Erfolg basiert auf:
+
+- Wahrscheinlichkeiten (Mathematik)
+- Einschätzung von Gegnern (Psychologie)
+- Positionsspiel und Timing
+        `;
+
+        document.getElementById("content").innerHTML =
+            marked.parse(markdown);
+
+        document.querySelectorAll("#content a").forEach(link => {
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documents/docs/networking/client-network-architecture.md

@@ -0,0 +1,249 @@
+# Client Nework Architecture
+<!-- vim-markdown-toc GFM -->
+
+* [Architecture Overview](#architecture-overview)
+    * [network/Card.java](#networkcardjava)
+    * [network/GameState.java](#networkgamestatejava)
+    * [network/Player.java](#networkplayerjava)
+    * [network/ChatClient.java](#networkchatclientjava)
+        * [ChatClient(ClientService clientService)](#chatclientclientservice-clientservice)
+        * [sendMessage(Message message)](#sendmessagemessage-message)
+        * [getMessages()](#getmessages)
+    * [network/ClientService.java](#networkclientservicejava)
+        * [ClientService(String ip, int port)](#clientservicestring-ip-int-port)
+        * [processCommand(String message)](#processcommandstring-message)
+        * [sendRequest(Runnable request)](#sendrequestrunnable-request)
+        * [getRuntimeException(Exception e)](#getruntimeexceptionexception-e)
+        * [closeSocket()](#closesocket)
+        * [writeToTransport(String s) throws IOException](#writetotransportstring-s-throws-ioexception)
+    * [network/CoreClient.java](#networkcoreclientjava)
+        * [CoreClient(ClientService clientservice)](#coreclientclientservice-clientservice)
+        * [ping()](#ping)
+        * [login(String user)](#loginstring-user)
+    * [network/GameClient.java](#networkgameclientjava)
+        * [GameClient(ClientService client)](#gameclientclientservice-client)
+        * [getGameState()](#getgamestate)
+        * [parseGameState(String input)](#parsegamestatestring-input)
+        * [Example server response](#example-server-response)
+    * [network/LobbyClient.java](#networklobbyclientjava)
+        * [LobbyClient(ClientService client)](#lobbyclientclientservice-client)
+        * [fetchLobbyStatusString(int lobbyId)](#fetchlobbystatusstringint-lobbyid)
+        * [createLobby()](#createlobby)
+        * [getLobbyId()](#getlobbyid)
+        * [joinLobby(int lobbyId)](#joinlobbyint-lobbyid)
+
+<!-- vim-markdown-toc -->
+
+## Architecture Overview
+
+```text
+client/
+ ├── game/
+ │    ├── Card.java
+ │    ├── GameState.java
+ │    └── Player.java
+ │
+ └── network/
+      ├── ChatClient.java
+      ├── ClientService.java
+      ├── CoreClient.java
+      ├── GameClient.java
+      └── LobbyClient.java
+```
+
+### game/Card.java
+
+Represents a playing card with a value and suit.
+
+### game/GameState.java
+
+Represents the current state of the poker game, including the phase, pot size, current bet, dealer position, active player, community cards, and player information.
+
+### game/Player.java
+
+Represents a player in the poker game, including their name, chip count, current bet, state (e.g., `active`, `folded`), and their hole cards.
+
+### network/ChatClient.java
+
+The ChatClient class is responsible for sending messages to the server and retrieving messages from the server. It uses the ClientService to send commands and receive responses from the server.
+
+#### ChatClient(ClientService clientService)
+
+Constructs a ChatClient with the given ClientService for communication.
+ 
+- **Parameter (`clientService`)**: The ClientService instance used to send commands and receive responses from the server.
+
+#### sendMessage(Message message)
+
+Send a Message to the server by converting it to a string format and sending a `SEND_MESSAGE` command with the message content as arguments.
+ 
+- **Parameter (`message`)**: message The Message object to be sent to the server.
+
+#### getMessages()
+
+Retrieve messages from the server by first sending a `GET_MESSAGE_COUNT` command to determine how many messages are available and then sending `GET_NEXT_MESSAGE` commands in a loop to retrieve each message. The retrieved messages are parsed into Message objects and returned as a list.
+ 
+- **Parameter (`A`)**: list of Message objects representing the messages retrieved from the server.
+
+### network/ClientService.java
+
+The ClientService class is responsible for managing the connection to the server, sending commands, and receiving responses. It uses a TcpTransport to
+communicate with the server and an ExecutorService to handle asynchronous requests.
+
+#### ClientService(String ip, int port)
+
+Constructs a ClientService with the given server IP and port. It establishes a socket connection to the server and initializes the TcpTransport and ExecutorService for communication.
+
+- **Parameter (`ip`)**: The IP address of the server to connect to.
+- **Parameter (`port`)**: The port number of the server to connect to.
+
+#### processCommand(String message)
+
+Sends a command to the server and waits for the response. The command is sent using the TcpTransport, and the response is read in a loop until a valid response is received. The method handles `+OK` and `-ERROR` responses from the server and returns the actual response content.
+
+- **Parameter (`message`)**: The command message to be sent to the server.
+- **Return**: The response from the server as a string.
+
+#### sendRequest(Runnable request)
+
+Helper method to send a request to the server using the ExecutorService. It submits the request as a Runnable task and waits for its completion. If the task is interrupted or encounters an execution exception, it throws a
+RuntimeException with the appropriate cause.
+ 
+- **Parameter (`request`)**: The Runnable task representing the request to be sent to the server.
+
+#### getRuntimeException(Exception e)
+
+Helper method to extract the cause of an exception and return it as a RuntimeException. If the cause is null, it returns the original exception as a RuntimeException. If the cause is already a RuntimeException, it returns it directly. Otherwise, it wraps the cause in a new RuntimeException and returns it.
+ 
+- **Parameter (`e`)**: The exception from which to extract the cause.
+- **Return**: A RuntimeException representing the cause of the original exception.
+
+#### closeSocket()
+
+Closes the socket connection to the server and shuts down the ExecutorService. It also closes the TcpTransport used for communication. If any IOException occurs during this process, it prints the exception to the console.
+
+#### writeToTransport(String s) throws IOException
+
+Helper method to write a command string to the TcpTransport. It generates a unique ID for the command using the idGenerator and sends a RawPacket containing the ID and the command string to the server. If an IOException occurs during this process, it throws a RuntimeException with the cause.
+ 
+- **Parameter (`s`)**: The command string to be sent to the server.
+- **Throws IOException**: If an I/O error occurs while writing to the transport.
+
+### network/CoreClient.java
+
+The CoreClient class provides basic functionalities for communicating with the server, such as sending a ping command to check connectivity and logging in with a username. It uses the ClientService to send commands and receive responses from the server.
+
+#### CoreClient(ClientService clientservice)
+
+Constructs a CoreClient with the given ClientService for communication.
+
+- **Parameter (`clientservice`)**: The ClientService instance used to send commands and receive responses from the server.
+
+#### ping()
+
+Sends a `PING` command to the server to check connectivity. The server should respond with a `PONG` message if the connection is successful.
+
+#### login(String user)
+
+Logs in to the server with the given username by sending a `LOGIN` command.
+
+- **Parameter (`user`)**: The username to log in with.
+
+### network/GameClient.java
+
+The GameClient class is responsible for communicating with the server to retrieve the current game state. It sends a command to the server and parses the response into a structured GameState object.
+
+#### GameClient(ClientService client)
+
+Constructs a GameClient with the given ClientService for communication.
+
+- **Parameter (`client`)**: The ClientService instance used to send commands and receive responses from the server.
+
+#### getGameState()
+
+Retrieves the current game state from the server by sending a command and parsing the response.
+
+- **Return**: A GameState object representing the current state of the game.
+
+#### parseGameState(String input)
+
+Parses the raw response from the server into a structured GameState object.
+
+- **Parameter (`input`)**: The raw response string from the server.
+- **Return**: A GameState object representing the current state of the game.
+
+#### Example server response
+
+```text
++OK
+    PHASE=FLO P
+    POT=150
+    CURRENT_BET=50
+    DEALER=0
+    ACTIVE_PLAYER=1
+    CARDS
+        CARD 
+            VALUE=10
+            SUIT=H
+        CARD 
+            VALUE=7
+            SUIT=S
+        CARD 
+            VALUE=A
+            SUIT=D
+    PLAYERS
+        PLAYER
+            NAME=Max
+            CHIPS=1200
+            BET=50
+            STATE=ACTIVE
+            CARDS
+                CARD 
+                    VALUE=K
+                    SUIT=H
+                CARD 
+                    VALUE=3
+                    SUIT=C
+        PLAYER
+            NAME=Anna
+            CHIPS=800
+            BET=0
+            STATE=FOLDED
+            CARDS
+END
+```
+
+### network/LobbyClient.java
+
+The LobbyClient class is responsible for communicating with the server to manage game lobbies. It provides methods to create a lobby, join a lobby, and fetch the current status of a lobby by sending appropriate commands to the server and processing the responses.
+
+#### LobbyClient(ClientService client)
+
+Constructs a LobbyClient with the given ClientService for communication.
+
+- **Parameter (`client`)**: The ClientService instance used to send commands and receive responses from the server.
+
+#### fetchLobbyStatusString(int lobbyId)
+
+Fetch the current status of the lobby with the given id from the server.
+
+- **Parameter (`lobbyId`)**: The id of the lobby to fetch the status for.
+- **Return**: A string representing the current status of the lobby, as returned by the server.
+
+#### createLobby()
+
+Request the server to create a new lobby and return the id of the newly created lobby.
+
+- **Return**: The id of the newly created lobby, as returned by the server.
+
+#### getLobbyId()
+
+Request the server to return the id of the lobby that the client is currently in.
+
+- **Return**: The id of the lobby that the client is currently in, as returned by the server.
+
+#### joinLobby(int lobbyId)
+
+Request the server to join the lobby with the given id.
+ 
+- **Parameter (`lobbyId`)**: The id of the lobby to join.

documents/docs/our-protocol.md

@@ -0,0 +1,72 @@
+# Our Network Protocol Documentation
+
+## Overview
+Our protocol is inspired by *POP3*, but has been highly customized to fit our specific needs.
+It is a text-based protocol operating over raw TCP sockets, designed for human readability and strict structure.
+
+## Packet Structure
+Each network packet consists of:
+- **4-byte header**: Specifies the size of the payload (big-endian integer).
+- **4-byte request ID**: Generated by the client, used to match requests and responses.
+- **Payload**: The actual data, its size as specified by the header.
+
+This structure is used for both requests and responses.
+
+## Conventions
+- All keys (in both requests and responses) use UPPER_SNAKE_CASE.
+- Only a-z, A-Z, 0-9 are allowed in keys.
+- Only human-readable strings are transmitted.
+- Binary data is not allowed.
+
+## Request Format
+A request consists of a single line:
+
+```
+COMMAND KEY1=ARG1 KEY2=ARG2
+```
+
+- **COMMAND**: The action to perform.
+- **KEY=VALUE pairs**: Optional parameters. There may be zero or more.
+- **Whitespace**: Extra spaces between key, separator, and value are ignored. Any other characters between them are an error.
+- **Standalone values**: Not allowed. Every value must have a key.
+
+### String Values
+- Strings with spaces must be enclosed in single quotes: `'example string'`.
+- Inside quoted strings, line breaks are allowed.
+- To include a single quote inside a string, escape it (e.g., `'It\'s fine'`).
+
+If these rules are violated, the request is considered invalid and will be rejected.
+
+## Response Format
+Responses are more complex and can represent nested collections.
+
+- **Success**: Starts with `+OK`
+- **Error**: Starts with `-ERR`
+- After the status, a newline follows, then fields in the format `KEY=VALUE`.
+- Collections and elements are ended with the `END` keyword.
+- A collection starts with a key, and its elements are indented.
+- A element starts with a key, and its fields are indented.
+
+### Example: Nested Collection
+```
++OK
+    KEY1=VALUE1
+    FIELDS
+        FIELD
+            NESTED_KEY=NESTED_VALUE
+        END
+    END
+    KEY2=VALUE2
+END
+```
+
+## Error Handling
+Any violation of the format (invalid characters, unescaped quotes, binary data, etc.) results in the request being rejected with an error response.
+
+### Example Error Response When Violating Syntax Rules:
+```
+-ERR
+    CODE=PARSING_ERROR
+    MSG='Error occured during parsing. Likely due to malformed payload.'
+END
+```

documents/milestones/ms-4/qa-concept.tex

@@ -0,0 +1,144 @@
+\documentclass{article}
+\setlength{\parindent}{0pt}
+\usepackage[a4paper,margin=2.5cm]{geometry}
+\usepackage{listings}
+
+% External links
+\usepackage{hyperref}
+
+% Colored text
+\usepackage{xcolor}
+
+% Customized table
+\usepackage{float}
+\usepackage{array}
+\newcolumntype{L}[1]{>{\raggedright\arraybackslash}p{#1}}
+\usepackage{booktabs}
+
+\title{QS-Konzept für MS4}
+\author{Syntax Syndicate - Casono}
+\begin{document}
+\maketitle
+
+
+\section{Einleitung}
+Dieses Dokument beschreibt die Software-Qualitätssicherung für unser Mehrspieler-Spiel \textit{Casono}. Es wird als Teil der Programmierprojekt-Vorlesung (ehemals bekannt als cs108) an der Universität Basel von uns entwickelt.\\
+
+Dieses Konzept basiert auf der \textit{DIN ISO 9126} und ist demzufolge in folgende Themenbereiche unterteilt:
+\begin{itemize}
+  \item \textbf{Konstruktives Qualitätsmanagement} - Maßnahmen, die \emph{während} der Entwicklung ergriffen werden, um die Qualität von Anfang an sicherzustellen.
+  Einschließlich technischer Standards, Werkzeuge und internen Organisation.
+  \item \textbf{Analytisches Qualitätsmanagement} - Maßnahmen zur \emph{Kontrolle und Untersuchung} des bestehenden Produkts, durch Anwendung automatisierte Analysen, Metrik-Schwellenwerte und Unit-Tests.
+\end{itemize}
+
+
+\section{Konstruktives Qualitätsmanagement}
+Ein konstruktives Qualitätsmanagement umfasst alle Maßnahmen, die proaktiv Mängel verhindern, indem gemeinsame Standards, Prozesse und Werkzeuge festgelegt werden, die jedes Teammitglied während der Entwicklung einhält.
+
+\subsection{Technische Maßnahmen}
+
+\subsubsection{JavaDoc}
+Alle öffentlichen Klassen, Interfaces, Records und Methoden müssen durch JavaDoc dokumentiert werden.\\
+Als Teil der GitLab-Build-Pipeline wird JavaDoc auf Richtigkeit überprüft. Werden strukturelle Fehler wie ungültige Referenzen erkannt, wird der Merge verhindert.\\
+Unsere aktuelle Grundlage sind daher 0 Fehler. Für den kommenden Meilenstein ist aber unser Ziel, die Regelungen weiter zu verschärfen, sodass auch Warnungen einen Merge verhindern.\\
+
+Unsere implizite Form für JavaDoc-Kommentare ist wie folgt:
+\begin{itemize}
+  \item Eine prägnante Zusammenfassung in einem Satz in der ersten Zeile
+  \item Zusätzliche Informationen oder Beispiele in weiteren Absätzen.
+  \item Dokumentation aller Parameter (\texttt{@param}), Rückgabewerte (\texttt{@return}) und Fehler (\texttt{@throws}).
+\end{itemize}
+Beginnend mit dem fünften Meilenstein soll diese Form ebenfalls durch einen Job in der CI-Pipeline überprüft werden.
+
+\newpage
+\subsubsection{Logging}
+Das Projekt verwendet Log4J~2 (\texttt{log4j-api} und \texttt{log4j-core} zur Laufzeit) zusammen mit Jansi für eine farbige Konsolenausgabe.
+Das Format der Ausgabe ist durch eine Konfigurationsdatei vereinheitlicht.\\
+
+Die Protokollstufen werden wie folgt einheitlich verwendet:
+\begin{itemize}
+  \item \texttt{DEBUG} für interne Zustandsänderungen
+  \item \texttt{INFO} für Lebenszyklusereignisse wie Serverstart, Verbindungsaufbau/-trennung des Clients
+  \item \texttt{WARN} für behebbare Anomalien
+  \item \texttt{ERROR} für nicht behebbare Fehler
+\end{itemize}
+
+\subsection{Organisatorische Maßnahmen}
+
+\subsubsection{Teamkultur und die \texttt{CONTRIBUTORS}-Datei}
+Das Stammverzeichnis des GitLab-Repositories enthält eine Datei namens \texttt{CONTRIBUTORS.md}, die die Teamkonventionen dokumentiert: 
+\begin{itemize}
+  \item Die Verwendung von Branches - Feature-Branches werden in \texttt{main} zusammengeführt
+  \item Merge-Richtlinie - CI muss bestanden werden. Keine ausdrückliche Genehmigung durch Kollegen erforderlich \footnote{Diese Regelung wird sich voraussichtlich ändern. Siehe dazu den Abschnitt zur \texttt{CODEOWNERS}-Datei.}
+  \item Namenskonventionen für Branches und Commits
+  \item Code-Stil - Google-Java-Format, AOSP-Variante, Einrückung mit vier Leerzeichen
+  \item Jede Änderung beginnt mit einem Issue oder Task in GitLab, bevor mit der Umsetzung begonnen wird
+  \item Branch-Namen folgen dem Muster \texttt{<typ>/<kurzbeschreibung>} gemäß \href{https://conventional-branch.github.io/}{Conventional Branch} Standard
+  \item Commit-Messages folgen dem \href{https://www.conventionalcommits.org/en/v1.0.0/}{Conventional Commits} Standard
+  \item Code-Style wird durch Linter (Checkstyle) und Formatter (Spotless, Google/AOSP Java Style) automatisiert überprüft
+  \item Merge Anfragen müssen eine Beschreibung enthalten und auf das zugehörige Issue oder den Task verweisen
+  \item Zusammenarbeit und Kommunikation erfolgen bevorzugt über Issue-Kommentare, nicht über private Nachrichten
+\end{itemize}
+
+\subsubsection{GitLab-Task- und Issue-Vorlagen für Fortschrittsverfolgung}
+GitLab-Vorlagen für Tasks und Issues werden für alle geplanten Arbeitselemente verwendet. Die Aufgabenvorlage sorgt für eine einheitliche Struktur, die die Fortschrittsverfolgung erleichtert und das Risiko vager oder unvollständiger Arbeitselemente reduziert.
+
+Durch die Vergabe von Labels kann Tasks und Issues weiterer Kontext gegeben werden.
+
+
+\newpage
+\section{Analytisches Qualitätsmanagement}
+\subsection{Analytische Verfahren}
+
+\subsubsection{Eigentumsrechte an Programmcode über GitLab \texttt{CODEOWNERS}}
+Beginnend mit dem fünften Meilenstein soll eine \texttt{CODEOWNERS}-Datei erstellt werden, welche Teammitgliedern die Eigentumsrechte an bestimmten Teilen des Programmcodes zuspricht.
+Wollen andere Teammitglieder Änderungen an diesen Teilen vornehmen, muss der Eigentümer sie freigeben.\\
+Aktuell ist jedoch noch unklar, ob diese Funktion genutzt werden kann, da die Instanz mindestens die \textit{Premium}-Stufe haben muss.
+
+\subsubsection{Automatisiertes CI-Linting und Build-Verifizierung}
+Jeder Push und jede Merge-Anfrage löst die CI-Pipeline aus.
+
+Für Pushes und Merge-Anfrage setzt sich die Pipeline aus folgenden Phasen zusammen:
+\begin{enumerate}
+  \item \textbf{Linting-Phase} \textcolor{blue}{[Push, MR]} - Checkstyle und Spotless überprüfen, ob der Programmcode dem vereinbarten Stil entspricht.
+  \item \textbf{Build-Phase} \textcolor{blue}{[Push, MR]} - \texttt{./gradlew assemble} prüft, ob das gesamte Projekt fehlerfrei kompiliert werden kann.
+  \item \textbf{Checkstyle-Report} \textcolor{blue}{[MR]} - Ein zusätzlicher Checkstyle-Report wird für Merge-Anfragen erzeugt und als Code-Quality-Report bereitgestellt.
+  \item \textbf{Javadoc-Prüfung} \textcolor{blue}{[MR]} - JavaDoc wird auf Korrektheit geprüft.
+  \item \textbf{Test-Phase} \textcolor{blue}{[Push, MR]} - Automatisierte Tests werden ausgeführt und ein Testreport erzeugt.
+\end{enumerate}
+Fehlschlagende Jobs verhindern einen Push nicht, jedoch wird ein Merge so lange verhindert, bis alle Jobs fehlerfrei abgeschlossen werden können.
+
+\subsection{Testverfahren}
+Unit-Tests werden mit \textit{JUnit 5} geschrieben und in der Testphase der CI-Pipeline ausgeführt. Ein fehlgeschlagener Test blockiert die Merge-Anfrage.
+
+Als weiteres Werkzeug verwenden wir \textit{JaCoCo} für die Ermittlung der Testabdeckung. \\
+Die aktuelle Testabdeckung ist wie folgt:
+
+\begin{table}[H]
+  \centering
+  \renewcommand{\arraystretch}{1.4}
+  \begin{tabular}{L{7.5cm} r r}
+    \toprule
+    \textbf{Paketname (gekürzt)}        & \textbf{Instr.\ Cov.} & \textbf{Branch Cov.} \\
+    \midrule
+    \texttt{client.chat}                                & 0\,\%  & 0\,\% \\
+    \texttt{client.game}                                & 0\,\%  & 0\,\% \\
+    \texttt{client.network}                             & 3\,\%  & 1\,\% \\
+    \texttt{client.ui} (von Abdeckung ausgeschlossen)   & 0\,\%  & 0\,\% \\
+    \texttt{server.app.checks}                          & 0\,\%  & 0\,\% \\
+    \texttt{server.app.commands}                        & 0\,\%  & 0\,\% \\
+    \texttt{server.domain.game}                         & 94\,\%  & 91\,\% \\
+    \texttt{server.domain.*}                            & 45\,\%  & 37\,\% \\
+    \texttt{server.network.transport}                   & 0\,\%  & 0\,\% \\
+    \texttt{server.network.protocol}                    & 0\,\%  & 0\,\% \\
+    \texttt{server.network.*}                           & 2\,\%  & 1\,\% \\
+    \midrule
+    \textbf{Summe}                          & \textbf{12\,\%} & \textbf{9\,\%} \\
+    \bottomrule
+  \end{tabular}
+\end{table}
+
+Unser Ziel ist es, realistische Anforderungen an unsere Testabdeckung zu stellen.
+Bis zum fünften Meilenstein wollen wir daher für wichtige Bereiche, wie die Game-Engine und interne Komponenten des Netzwerks, eine möglichst hohe Abdeckung von mindestens 50\% erzielen. 
+
+\end{document}

src/main/java/ch/unibas/dmi/dbis/cs108/casono/Main.java

@@ -7,6 +7,12 @@ import org.apache.logging.log4j.Logger;
 
 /** Main entry point for Casono application. Handles client and server startup. */
 public final class Main {
+
+    private static final int MIN_ARGS_FOR_USERNAME = 3;
+    private static final int ARGS_COUNT_SERVER = 2;
+    private static final int ARGS_COUNT_CLIENT_MIN = 2;
+    private static final int ARGS_COUNT_CLIENT_WITH_USER = 3;
+
     /**
      * Main entry point for Casono.
      *
@@ -17,10 +23,13 @@ public final class Main {
             printUsage();
             System.exit(1);
         }
-
         switch (args[0]) {
             case "server" -> ServerApp.start(args[1]);
-            case "client" -> ClientApp.start(args[1]);
+            case "client" -> {
+                String address = args[1];
+                String username = args.length >= MIN_ARGS_FOR_USERNAME ? args[2] : null;
+                ClientApp.start(address, username);
+            }
             default -> {
                 printUsage();
                 System.exit(1);
@@ -29,12 +38,15 @@ public final class Main {
     }
 
     private static boolean isValid(String[] args) {
-        if (args.length != 2) {
+        if (args.length < ARGS_COUNT_SERVER) {
             return false;
         }
 
         return switch (args[0]) {
-            case "server", "client" -> true;
+            case "server" -> args.length == ARGS_COUNT_SERVER;
+            case "client" ->
+                    args.length == ARGS_COUNT_CLIENT_MIN
+                            || args.length == ARGS_COUNT_CLIENT_WITH_USER;
             default -> false;
         };
     }
@@ -45,7 +57,7 @@ public final class Main {
                 """
                 Usage:
                   java -jar xyz.jar server <listenPort>
-                  java -jar xyz.jar client <serverIp>:<serverPort>
+                  java -jar xyz.jar client <serverIp>:<serverPort> [<username>]
                 """);
     }
 }

src/main/java/ch/unibas/dmi/dbis/cs108/casono/client/ClientApp.java

@@ -1,41 +1,131 @@
 package ch.unibas.dmi.dbis.cs108.casono.client;
 
-/**
- * Entry point for the Casono client application. Handles client startup and connection parameters.
- */
+import ch.unibas.dmi.dbis.cs108.casono.client.network.ClientService;
+import ch.unibas.dmi.dbis.cs108.casono.client.network.LobbyClient;
+import ch.unibas.dmi.dbis.cs108.casono.client.network.LoginResult;
 import ch.unibas.dmi.dbis.cs108.casono.client.ui.Launcher;
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 
 /**
- * Entry point for the Casono client application. Handles client startup and connection parameters.
+ * Entry point and bootstrap helper for the Casono client application.
  *
- * <p>Default constructor for the application.
+ * <p>Responsibilities: - Parse CLI args (host:port, optional username) - Store username centrally
+ * so UI can reuse it - Create a shared ClientService and do startup LOGIN
  */
 public class ClientApp {
 
     private static final Logger LOGGER = LogManager.getLogger(ClientApp.class);
 
+    /** Shared client connection used when a username is provided at startup. */
+    private static volatile ClientService sharedClientService;
+
+    private static volatile String sharedUsername;
+
     /** Default constructor. */
     public ClientApp() {
         // Default constructor
     }
 
-    /**
-     * Starts the client application with the given address.
-     *
-     * @param arg Address in the format "ip:port".
-     * @throws IllegalArgumentException if the address format is invalid.
-     */
-    public static void start(String arg) {
+    public static ClientService getSharedClientService() {
+        return sharedClientService;
+    }
+
+    private static void setSharedClientService(ClientService cs) {
+        sharedClientService = cs;
+    }
+
+    public static String getSharedUsername() {
+        return sharedUsername;
+    }
+
+    public static void updateSharedUsername(String username) {
+        setSharedUsername(normalizeUsername(username));
+    }
+
+    private static String normalizeUsername(String username) {
+        if (username == null || username.isBlank()) {
+            return null;
+        }
+        return username.trim();
+    }
+
+    private static void setSharedUsername(String username) {
+        sharedUsername = username;
+        LOGGER.info("sharedUsername set to '{}'", getSharedUsername());
+    }
+
+    public static void start(String arg, String username) {
+        String[] hostPort = parseHostAndPort(arg);
+        String host = hostPort[0];
+        int port = Integer.parseInt(hostPort[1]);
+        String normalizedUsername = normalizeUsername(username);
+
+        configureServerProperties(host, port);
+        setSharedUsername(normalizedUsername);
+
+        performStartupLogin(host, port, normalizedUsername);
+
+        launchUI(arg);
+    }
+
+    private static String[] parseHostAndPort(String arg) {
         String[] parts = arg.split(":", 2);
         if (parts.length != 2) {
-            throw new IllegalArgumentException("Address must be in format <ip>:<port>.");
+            throw new IllegalArgumentException("The address must be in the format <ip>:<port>.");
         }
-        String host = parts[0];
-        int port = Integer.parseInt(parts[1]);
+        return parts;
+    }
 
+    private static void configureServerProperties(String host, int port) {
         LOGGER.info("You've selected the client. It will connect port {} at host {}", port, host);
-        Launcher.main(new String[] {});
+        System.setProperty("casono.server.host", host);
+        System.setProperty("casono.server.port", String.valueOf(port));
+    }
+
+    private static void performStartupLogin(String host, int port, String username) {
+        try {
+            ClientService clientService = new ClientService(host, port);
+            setSharedClientService(clientService);
+            LobbyClient lobbyClient = new LobbyClient(clientService);
+            LoginResult res = lobbyClient.login(username);
+
+            if (res != null && res.getUsername() != null && !res.getUsername().isBlank()) {
+                setSharedUsername(res.getUsername().trim());
+            }
+
+            String assignedUsername = null;
+            String assignedId = null;
+            if (res != null) {
+                assignedUsername = res.getUsername();
+                assignedId = res.getId();
+            }
+            LOGGER.info("Assigned username='{}' id={}", assignedUsername, assignedId);
+        } catch (RuntimeException e) {
+            LOGGER.warn(
+                    "Could not establish initial connection for startup login: {}", e.getMessage());
+        }
+    }
+
+    private static void launchUI(String arg) {
+        String username = getSharedUsername();
+        if (username == null || username.isBlank()) {
+            Launcher.main(new String[] {arg});
+            return;
+        }
+        Launcher.main(new String[] {arg, username});
+    }
+
+    public static void main(String[] args) {
+        if (args == null || args.length == 0) {
+            throw new IllegalArgumentException("Address argument required: <host:port>");
+        }
+
+        String username = null;
+        if (args.length > 1) {
+            username = normalizeUsername(args[1]);
+        }
+
+        start(args[0], username);
     }
 }

src/main/java/ch/unibas/dmi/dbis/cs108/casono/client/chat/ChatController.java

@@ -0,0 +1,383 @@
+package ch.unibas.dmi.dbis.cs108.casono.client.chat;
+
+import ch.unibas.dmi.dbis.cs108.casono.client.ClientApp;
+import ch.unibas.dmi.dbis.cs108.casono.client.network.ChatClient;
+import ch.unibas.dmi.dbis.cs108.casono.client.network.ClientService;
+import ch.unibas.dmi.dbis.cs108.casono.client.ui.chatui.ChatBoxController;
+import ch.unibas.dmi.dbis.cs108.casono.client.ui.chatui.ChatViewController;
+import ch.unibas.dmi.dbis.cs108.casono.server.network.command.parsing.RequestParameter;
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.LinkedHashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+import java.util.Timer;
+import java.util.TimerTask;
+import java.util.WeakHashMap;
+import java.util.function.Consumer;
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+import org.jspecify.annotations.Nullable;
+
+/**
+ * responsible for the transferring of messages from the server to the ChatModel or from the
+ * ChatViewController to the server
+ */
+public class ChatController {
+
+    /** Ensures one active message poller per physical ClientService connection. */
+    private static final Map<ClientService, ChatController> ACTIVE_CONTROLLERS =
+            new WeakHashMap<>();
+
+    private volatile String username;
+
+    private final ClientService clientService;
+
+    private final ChatClient chatClient;
+
+    public ChatBoxController getChatBoxController() {
+        return chatBoxController;
+    }
+
+    public void setChatBoxController(ChatBoxController chatBoxController) {
+        this.chatBoxController = chatBoxController;
+    }
+
+    private ChatBoxController chatBoxController;
+    private int lobbyId = -1;
+    private final Timer timer;
+    private final Consumer<List<String>> serverEventListener;
+
+    public record ChatKey(ChatType type, @Nullable String targetUser) {
+        public ChatKey(ChatType type) {
+            this(type, null);
+        }
+    }
+
+    public Map<ChatKey, ChatModel> getChatModelMap() {
+        return chatModelMap;
+    }
+
+    private final Map<ChatKey, ChatModel> chatModelMap;
+
+    private static final long REFRESH_TIME = 1000;
+
+    /** List of all users connected to the server, to safe them locally on the client */
+    private final List<String> localUserList;
+
+    public List<String> getLocalUserList() {
+        return this.localUserList;
+    }
+
+    public final Map<ChatController.ChatKey, ChatViewController> activeChatControllers;
+
+    private final Logger logger;
+
+    /**
+     * Constructor, adds TimerTask to be sent to the server regularly
+     *
+     * @param username
+     * @param clientService
+     */
+    public ChatController(String username, ClientService clientService) {
+        this.username = username;
+        this.clientService = clientService;
+        chatClient = new ChatClient(clientService);
+        chatModelMap = new LinkedHashMap<>();
+        localUserList = new ArrayList<>();
+        this.chatBoxController = new ChatBoxController(username, this);
+        this.logger = LogManager.getLogger(ChatController.class);
+        this.serverEventListener = this::handleServerEvent;
+        this.activeChatControllers = new HashMap<>();
+
+        registerAsActiveController(clientService);
+        clientService.addEventListener(serverEventListener);
+
+        this.timer = new Timer(true);
+        timer.schedule(
+                new TimerTask() {
+                    @Override
+                    public void run() {
+                        try {
+                            receiveMessage();
+                            checkWhisperUsers();
+                        } catch (RuntimeException e) {
+                            logger.warn("Chat refresh failed: {}", e.getMessage());
+                        }
+                    }
+                },
+                0,
+                REFRESH_TIME);
+    }
+
+    private void registerAsActiveController(ClientService clientService) {
+        synchronized (ACTIVE_CONTROLLERS) {
+            ChatController oldController = ACTIVE_CONTROLLERS.get(clientService);
+            if (oldController != null && oldController != this) {
+                oldController.shutdown();
+                logger.info("Replaced previous ChatController poller for shared ClientService");
+            }
+            ACTIVE_CONTROLLERS.put(clientService, this);
+        }
+    }
+
+    /**
+     * Method to be activated, if a lobby has been chosen. It will update the UI and add a new
+     * ChatModel to hold the Data for the Lobby Chat
+     *
+     * @param lobbyId
+     */
+    public void setLobbyChat(int lobbyId) {
+        this.lobbyId = lobbyId;
+        ChatKey key = new ChatKey(ChatType.LOBBY);
+        ChatModel existingModel = chatModelMap.get(key);
+        if (existingModel != null) {
+            existingModel.lobbyId = lobbyId;
+            return;
+        }
+        ChatModel lobbyChatModel = new ChatModel(ChatType.LOBBY, username, lobbyId, null);
+        chatModelMap.put(key, lobbyChatModel);
+        this.chatBoxController.addChatTab("LOBBY", lobbyChatModel, ChatType.LOBBY);
+    }
+
+    /**
+     * Method to process the Messages that got polled by the {@link ChatClient}.
+     *
+     * <p>Case distinction for every message: - Messages identified with ChatType.LOBBY -> check if
+     * they belong to the users lobby. - Messages identified with ChatType.GLOBAL -> check if the
+     * target user of that Message is the user, or the message got sent by the user.
+     *
+     * <p>All Messages get added to a particular {@link ChatModel}, if the checks passed.
+     */
+    public void receiveMessage() {
+        String currentUsername = getCurrentUsername();
+        List<Message> newMessages = chatClient.getMessages();
+        if (!newMessages.isEmpty()) {
+            for (Message msg : newMessages) {
+                switch (msg.getMessageType()) {
+                    case ChatType.GLOBAL:
+                        chatModelMap.get(new ChatKey(ChatType.GLOBAL)).addMessage(msg);
+                        break;
+                    case ChatType.LOBBY:
+                        if (msg.lobbyId == getActiveLobbyChatId()) {
+                            chatModelMap
+                                    .computeIfAbsent(
+                                            new ChatKey(ChatType.LOBBY),
+                                            (_key) ->
+                                                    new ChatModel(
+                                                            ChatType.LOBBY,
+                                                            currentUsername,
+                                                            msg.lobbyId,
+                                                            null))
+                                    .addMessage(msg);
+                        }
+                        break;
+                    case ChatType.WHISPER:
+                        if (msg.target.equals(currentUsername)
+                                || msg.sender.equals(currentUsername)) {
+                            ChatKey key;
+                            if (msg.target.equals(currentUsername)) {
+                                key = new ChatKey(ChatType.WHISPER, msg.sender);
+                            } else {
+                                key = new ChatKey(ChatType.WHISPER, msg.target);
+                            }
+                            if (chatModelMap.containsKey(key)) {
+                                chatModelMap.get(key).addMessage(msg);
+                            } else {
+                                ChatModel chatModel =
+                                        new ChatModel(
+                                                ChatType.WHISPER,
+                                                currentUsername,
+                                                lobbyId,
+                                                key.targetUser());
+                                chatBoxController.addWhisperChat(key.targetUser(), chatModel);
+                                chatModel.addMessage(msg);
+                            }
+                        }
+                        break;
+                }
+            }
+        }
+    }
+
+    /**
+     * Method to get the lobbyId of the currently active lobby chat, to check if incoming lobby
+     * messages belong to the same lobby.
+     *
+     * @return the lobbyId of the currently active lobby chat.
+     */
+    private int getActiveLobbyChatId() {
+        ChatModel lobbyModel = chatModelMap.get(new ChatKey(ChatType.LOBBY));
+        if (lobbyModel != null) {
+            return lobbyModel.lobbyId;
+        }
+        return lobbyId;
+    }
+
+    /**
+     * Method to process the usernames of other users connected to the server, after they got polled
+     * by the {@link ChatClient}.
+     *
+     * <p>Checks for every one of the usernames, if it is already in the list localUserList and if
+     * not adds them. For every new User added in the List, they get added as an option to start a
+     * Whisper Chat with.
+     */
+    public synchronized void checkWhisperUsers() {
+        List<String> users = chatClient.getUsers();
+        Set<String> remoteUsers = new HashSet<>();
+        String currentUsername = getCurrentUsername();
+
+        for (String user : users) {
+            if (user == null || !user.contains("=")) {
+                continue;
+            }
+            String value = user.split("\\=", 2)[1].trim();
+            if (value.isBlank() || value.equals(currentUsername)) {
+                continue;
+            }
+            remoteUsers.add(value);
+        }
+
+        for (String known : new ArrayList<>(localUserList)) {
+            if (!remoteUsers.contains(known)) {
+                localUserList.remove(known);
+                chatBoxController.removeWhisperUser(known);
+            }
+        }
+
+        for (String remote : remoteUsers) {
+            addWhisperUser(remote);
+        }
+    }
+
+    /**
+     * Registers a whisper target locally and updates the UI if it is a new user.
+     *
+     * @param user target username
+     */
+    public synchronized void addWhisperUser(String user) {
+        if (user == null || user.isBlank()) {
+            return;
+        }
+        if (!(localUserList.contains(user) || user.equals(getCurrentUsername()))) {
+            localUserList.add(user);
+            logger.info("adding new whisper user");
+            chatBoxController.addWhisperUser(user);
+        }
+    }
+
+    public synchronized void updateUsername(String newUsername) {
+        if (newUsername == null || newUsername.isBlank()) {
+            return;
+        }
+        String oldUsername = this.username;
+        this.username = newUsername.trim();
+        chatBoxController.setUsername(this.username);
+
+        if (oldUsername != null && !oldUsername.equals(this.username)) {
+            localUserList.remove(oldUsername);
+            chatBoxController.removeWhisperUser(oldUsername);
+        }
+    }
+
+    private void handleServerEvent(List<String> lines) {
+        if (lines == null || lines.isEmpty()) {
+            return;
+        }
+
+        List<RequestParameter> params;
+        try {
+            params = ClientService.convertToRequestParameters(lines);
+        } catch (RuntimeException e) {
+            return;
+        }
+        String event = null;
+        String oldUsername = null;
+        String newUsername = null;
+
+        for (RequestParameter p : params) {
+            if ("EVENT".equalsIgnoreCase(p.key())) {
+                event = p.value();
+            } else if ("OLD_USERNAME".equalsIgnoreCase(p.key())) {
+                oldUsername = p.value();
+            } else if ("NEW_USERNAME".equalsIgnoreCase(p.key())) {
+                newUsername = p.value();
+            }
+        }
+
+        if (!"USERNAME_CHANGED".equalsIgnoreCase(event)) {
+            return;
+        }
+
+        applyUsernameMigration(oldUsername, newUsername);
+    }
+
+    private synchronized void applyUsernameMigration(String oldUsername, String newUsername) {
+        if (oldUsername == null
+                || newUsername == null
+                || oldUsername.isBlank()
+                || newUsername.isBlank()
+                || oldUsername.equals(newUsername)) {
+            return;
+        }
+
+        String currentUsername = getCurrentUsername();
+        if (oldUsername.equals(currentUsername)) {
+            updateUsername(newUsername);
+        }
+
+        ChatKey oldKey = new ChatKey(ChatType.WHISPER, oldUsername);
+        ChatKey newKey = new ChatKey(ChatType.WHISPER, newUsername);
+
+        ChatModel oldModel = chatModelMap.remove(oldKey);
+        ChatModel existingNewModel = chatModelMap.get(newKey);
+        if (oldModel != null) {
+            oldModel.setTarget(newUsername);
+            if (existingNewModel == null) {
+                chatModelMap.put(newKey, oldModel);
+            } else {
+                // Merge possible parallel history into the already existing new-key model.
+                for (Message msg : oldModel.messages) {
+                    existingNewModel.addMessage(msg);
+                }
+            }
+            chatBoxController.renameWhisperUser(oldUsername, newUsername);
+        }
+
+        localUserList.remove(oldUsername);
+        chatBoxController.removeWhisperUser(oldUsername);
+        if (!newUsername.equals(getCurrentUsername())) {
+            addWhisperUser(newUsername);
+        }
+    }
+
+    public String getCurrentUsername() {
+        String shared = ClientApp.getSharedUsername();
+        if (shared != null && !shared.isBlank()) {
+            return shared.trim();
+        }
+        return username;
+    }
+
+    /** Stops polling background tasks for this chat controller instance. */
+    public void shutdown() {
+        timer.cancel();
+        clientService.removeEventListener(serverEventListener);
+        synchronized (ACTIVE_CONTROLLERS) {
+            if (ACTIVE_CONTROLLERS.get(clientService) == this) {
+                ACTIVE_CONTROLLERS.remove(clientService);
+            }
+        }
+    }
+
+    /**
+     * method to send a message to the server
+     *
+     * @param message
+     */
+    public void onSendToNetwork(Message message) {
+        chatClient.sendMessage(message);
+    }
+}

src/main/java/ch/unibas/dmi/dbis/cs108/casono/client/chat/ChatModel.java

@@ -0,0 +1,89 @@
+package ch.unibas.dmi.dbis.cs108.casono.client.chat;
+
+import java.util.ArrayList;
+import java.util.function.Consumer;
+import javafx.beans.property.IntegerProperty;
+import javafx.beans.property.SimpleIntegerProperty;
+
+/**
+ * ChatModel, stores the data for a specific chat
+ *
+ * <p>Holds the current state of a chat
+ */
+public class ChatModel {
+
+    private ArrayList<Consumer<Message>> listeners = new ArrayList<>();
+
+    public ArrayList<Message> messages;
+
+    private final ChatType chattype;
+
+    /** The person currently using this client */
+    public final String username;
+
+    /** The person to send the message to If the chat is a whisper chat */
+    private String target;
+
+    private final IntegerProperty count;
+
+    public int lobbyId;
+
+    /**
+     * Constructs a new ChatModel for a specific chat type.
+     *
+     * @param chattype The type of chat (e.g., GLOBAL, LOBBY, or WHISPER).
+     * @param username The username of the current user.
+     * @param lobbyId The ID of the lobby, or -1 if not applicable.
+     * @param target The username of the whisper recipient, or null for other chat types.
+     */
+    public ChatModel(ChatType chattype, String username, int lobbyId, String target) {
+        this.messages = new ArrayList<Message>();
+        this.chattype = chattype;
+        this.username = username;
+        this.count = new SimpleIntegerProperty(0);
+        this.lobbyId = lobbyId;
+        this.target = target;
+    }
+
+    /**
+     * Returns the type of chat this model represents.
+     *
+     * @return The {@link ChatType}.
+     */
+    public ChatType getChattype() {
+        return chattype;
+    }
+
+    /**
+     * Adds a new message to the history and notifies all registered listeners. This method is
+     * synchronized to ensure thread safety when updating the message list.
+     *
+     * @param msg The {@link Message} to be added.
+     */
+    public synchronized void addMessage(Message msg) {
+        messages.add(msg);
+        listeners.stream().forEach((l) -> l.accept(messages.getLast()));
+    }
+
+    /**
+     * Registers a listener to be notified whenever a new message is added to this model.
+     *
+     * @param listener A {@link Consumer} that processes the new {@link Message}.
+     */
+    public void addListener(Consumer<Message> listener) {
+        this.listeners.add(listener);
+    }
+
+    /**
+     * Returns the target user for this chat, primarily used for whispers.
+     *
+     * @return The target username or null.
+     */
+    public String getTarget() {
+        return target;
+    }
+
+    public void setTarget(String target) {
+        this.target = target;
+    }
+}

src/main/java/ch/unibas/dmi/dbis/cs108/casono/client/chat/ChatType.java

@@ -0,0 +1,8 @@
+package ch.unibas.dmi.dbis.cs108.casono.client.chat;
+
+/** Describing the Type of the Chat */
+public enum ChatType {
+    GLOBAL,
+    LOBBY,
+    WHISPER
+}

src/main/java/ch/unibas/dmi/dbis/cs108/casono/client/chat/Message.java

@@ -0,0 +1,209 @@
+package ch.unibas.dmi.dbis.cs108.casono.client.chat;
+
+import ch.unibas.dmi.dbis.cs108.casono.server.network.command.parsing.RequestParameter;
+import ch.unibas.dmi.dbis.cs108.casono.server.network.protocol.response.builder.ResponseBody;
+import ch.unibas.dmi.dbis.cs108.casono.server.network.protocol.response.builder.ResponseBodyBuilder;
+import java.time.LocalDateTime;
+import java.time.format.DateTimeFormatter;
+import java.util.List;
+import java.util.Optional;
+import org.jspecify.annotations.NonNull;
+
+/** Message Object for internal handling of Chat-Messages */
+public class Message {
+    private final ChatType type;
+    private final String message;
+    public String sender;
+    public String timestamp;
+    public int lobbyId = 0;
+    public String target = null;
+
+    /**
+     * Constructs a Message with a provided timestamp. Typically used when reconstructing messages
+     * received from the server. Used for Messages in the Lobby Chat.
+     *
+     * @param lobbyId The ID of the lobby, or -1 if not applicable.
+     * @param sender The username of the message creator.
+     * @param timestamp The formatted time string (e.g., "HH:mm").
+     * @param message The actual text content of the message.
+     */
+    private Message(int lobbyId, String sender, String timestamp, String message) {
+        this.type = ChatType.LOBBY;
+        this.lobbyId = lobbyId;
+        this.sender = sender;
+        this.target = null;
+        this.timestamp = timestamp;
+        this.message = message;
+    }
+
+    /**
+     * Constructs a Message with a provided timestamp. Typically used when reconstructing messages
+     * received from the server. Used for Messages in the WHISPER and GLOBAL Chat.
+     *
+     * @param type The chat category (e.g., GLOBAL or WHISPER).
+     * @param sender The username of the message creator.
+     * @param timestamp The formatted time string (e.g., "HH:mm").
+     * @param message The actual text content of the message.
+     */
+    private Message(ChatType type, String sender, String target, String timestamp, String message) {
+        this.type = type;
+        this.lobbyId = -1;
+        this.sender = sender;
+        this.target = target;
+        this.timestamp = timestamp;
+        this.message = message;
+    }
+
+    /**
+     * Constructs a new Message for the current user. Automatically generates a timestamp based on
+     * the local system time ("HH:mm").
+     *
+     * @param type The chat category (e.g., GLOBAL, LOBBY, or WHISPER).
+     * @param lobbyId The ID of the lobby, or -1 if not applicable.
+     * @param sender The username of the current user.
+     * @param target The username of the recipient (for whispers).
+     * @param message The actual text content to be sent.
+     */
+    public Message(ChatType type, int lobbyId, String sender, String target, String message) {
+        this.type = type;
+        this.lobbyId = lobbyId;
+        this.sender = sender;
+        this.target = target;
+        this.message = message;
+        LocalDateTime now = LocalDateTime.now();
+        DateTimeFormatter formatter = DateTimeFormatter.ofPattern("HH:mm");
+        this.timestamp = now.format(formatter);
+    }
+
+    /**
+     * Returns the text content of the message.
+     *
+     * @return The message string.
+     */
+    public String getMessage() {
+        return message;
+    }
+
+    /**
+     * Returns the type of chat this message belongs to.
+     *
+     * @return The {@link ChatType}.
+     */
+    public ChatType getMessageType() {
+        return type;
+    }
+
+    /**
+     * Formats the message object into a string representation compatible with the network protocol
+     * arguments.
+     *
+     * @return A formatted string containing all message attributes for server transmission.
+     */
+    public String toArgsString() {
+        String gameIdString = "";
+        if (lobbyId >= 0) {
+            gameIdString = " GAME=" + lobbyId;
+        } else {
+            gameIdString = " GAME='-1'";
+        }
+        return String.format(
+                "TYPE=%s%s USER='%s' TARGET='%s' TIME='%s' TEXT='%s'",
+                this.type.toString(),
+                gameIdString,
+                this.sender,
+                this.target,
+                this.timestamp,
+                this.message);
+    }
+
+    /**
+     * Parses a list of network request parameters to reconstruct a Message object. Handles
+     * different chat types (GLOBAL, LOBBY, WHISPER) and their specific requirements.
+     *
+     * @param parameters A list of {@link RequestParameter} received from the network.
+     * @return A new {@link Message} instance populated with the parsed data.
+     */
+    public static Message toMessageReqPars(List<RequestParameter> parameters) {
+        String typeString = getParString(parameters, "TYPE");
+        ChatType type = ChatType.valueOf(typeString);
+        return switch (type) {
+            case GLOBAL ->
+                    new Message(
+                            ChatType.GLOBAL,
+                            getParString(parameters, "USER"),
+                            null,
+                            getParString(parameters, "TIME"),
+                            getParString(parameters, "TEXT"));
+            case LOBBY ->
+                    new Message(
+                            Integer.parseInt(getParString(parameters, "GAME")),
+                            getParString(parameters, "USER"),
+                            getParString(parameters, "TIME"),
+                            getParString(parameters, "TEXT"));
+            case WHISPER ->
+                    new Message(
+                            ChatType.WHISPER,
+                            getParString(parameters, "USER"),
+                            getParString(parameters, "TARGET"),
+                            getParString(parameters, "TIME"),
+                            getParString(parameters, "TEXT"));
+        };
+    }
+
+    /**
+     * Helper method to extract a specific parameter value by its key.
+     *
+     * @param parameters The list of parameters to search.
+     * @param keyString The key to look for.
+     * @return The value associated with the key.
+     * @throws RuntimeException if the key is not found.
+     */
+    private static @NonNull String getParString(
+            List<RequestParameter> parameters, String keyString) {
+        return getParString(parameters, keyString, null);
+    }
+
+    /**
+     * Helper method to extract a specific parameter value by its key, with a fallback default
+     * value.
+     *
+     * @param parameters The list of parameters to search.
+     * @param keyString The key to look for.
+     * @param defaultVal The value to return if the key is missing.
+     * @return The found value or the default value.
+     */
+    private static @NonNull String getParString(
+            List<RequestParameter> parameters, String keyString, String defaultVal) {
+        Optional<String> parOption =
+                parameters.stream()
+                        .filter((p) -> keyString.equals(p.key()))
+                        .findFirst()
+                        .map(RequestParameter::value);
+        if (parOption.isEmpty()) {
+            if (defaultVal == null) {
+                throw new RuntimeException("No " + keyString + " found");
+            } else {
+                return defaultVal;
+            }
+        }
+        return parOption.get();
+    }
+
+    /**
+     * Converts the message object into a network response body using the provided builder.
+     *
+     * @param builder The {@link ResponseBodyBuilder} used to construct the response.
+     * @return The built {@link ResponseBody} containing the message data.
+     */
+    public ResponseBody toResponse(ResponseBodyBuilder builder) {
+        builder.param("TYPE", type.name());
+        builder.param("GAME", lobbyId);
+        builder.param("USER", this.sender);
+        if (target != null) {
+            builder.param("TARGET", target);
+        }
+        builder.param("TIME", this.timestamp);
+        builder.param("TEXT", this.message);
+        return builder.build();
+    }
+}

src/main/java/ch/unibas/dmi/dbis/cs108/casono/client/game/Card.java

@@ -0,0 +1,54 @@
+package ch.unibas.dmi.dbis.cs108.casono.client.game;
+
+/** Represents a playing card with a value and suit. */
+public class Card {
+    private String value;
+    private String suit;
+
+    /**
+     * Constructs a Card with the specified value and suit.
+     *
+     * @param value The value of the card (e.g., 2, 3, ..., 10, J, Q, K, A).
+     * @param suit The suit of the card (e.g., Hearts, Diamonds, Clubs, Spades).
+     */
+    public Card(String value, String suit) {
+        this.value = value;
+        this.suit = suit;
+    }
+
+    /**
+     * Retrieves the value of the card.
+     *
+     * @return The value of the card.
+     */
+    public String getValue() {
+        return value;
+    }
+
+    /**
+     * Retrieves the suit of the card.
+     *
+     * @return The suit of the card.
+     */
+    public String getSuit() {
+        return suit;
+    }
+
+    /**
+     * Sets the value of the card.
+     *
+     * @param value The value to set for the card.
+     */
+    public void setValue(String value) {
+        this.value = value;
+    }
+
+    /**
+     * Sets the suit of the card.
+     *
+     * @param suit The suit to set for the card.
+     */
+    public void setSuit(String suit) {
+        this.suit = suit;
+    }
+}

src/main/java/ch/unibas/dmi/dbis/cs108/casono/client/game/GameService.java

@@ -0,0 +1,156 @@
+package ch.unibas.dmi.dbis.cs108.casono.client.game;
+
+import ch.unibas.dmi.dbis.cs108.casono.client.network.GameClient;
+import java.util.List;
+import java.util.logging.Level;
+import java.util.logging.Logger;
+
+public class GameService {
+
+    private static final Logger LOG = Logger.getLogger(GameService.class.getName());
+
+    private final GameClient client;
+    private GameState state;
+
+    /**
+     * Constructs a GameService with the specified GameClient.
+     *
+     * @param client The GameClient used to communicate with the server. Must not be null.
+     */
+    public GameService(GameClient client) {
+        if (client == null) {
+            throw new IllegalArgumentException("GameClient must not be null");
+        }
+
+        this.client = client;
+        LOG.info("GameService created");
+    }
+
+    /**
+     * Refreshes the game state by fetching the latest state from the server using the GameClient.
+     *
+     * @return The updated GameState after refreshing.
+     */
+    public GameState refresh() {
+        LOG.fine("Refreshing game state...");
+
+        GameState newState;
+        try {
+            newState = client.fetchGameState();
+        } catch (Exception e) {
+            // Shouldn't happen with the new GameClient, but keep service stable.
+            LOG.log(Level.WARNING, "refresh() failed: " + e.getMessage(), e);
+            return state;
+        }
+
+        if (newState == null) {
+            LOG.fine("No new state (null) -> keeping previous state");
+            return state;
+        }
+
+        this.state = newState;
+
+        LOG.info(
+                () ->
+                        "State updated: phase="
+                                + state.phase
+                                + " pot="
+                                + state.pot
+                                + " players="
+                                + (state.players != null ? state.players.size() : 0)
+                                + " community="
+                                + (state.communityCards != null ? state.communityCards.size() : 0));
+
+        return state;
+    }
+
+    /**
+     * Retrieves the current phase of the game.
+     *
+     * @return The current game phase as a string (e.g., "Pre-Flop", "Flop", "Turn", "River").
+     */
+    public int getPot() {
+        ensureState();
+        return state.pot;
+    }
+
+    /**
+     * Retrieves the current phase of the game.
+     *
+     * @return The current game phase as a string (e.g., "Pre-Flop", "Flop", "Turn", "River").
+     */
+    public List<Card> getCommunityCards() {
+        ensureState();
+        return state.communityCards != null ? state.communityCards : List.of();
+    }
+
+    /**
+     * Retrieves the list of players currently in the game.
+     *
+     * @return A list of Player objects representing the players in the game. A list of Player
+     *     objects representing the players in the game.
+     */
+    public List<Player> getPlayers() {
+        ensureState();
+        return state.players != null ? state.players : List.of();
+    }
+
+    /**
+     * Retrieves the index of the current player whose turn it is.
+     *
+     * @return The index of the current player in the players list, or -1 if not available.
+     */
+    public Player getWinner() {
+        ensureState();
+        if (state.winnerIndex < 0
+                || state.players == null
+                || state.winnerIndex >= state.players.size()) {
+            return null;
+        }
+        return state.players.get(state.winnerIndex);
+    }
+
+    /** Retrieves the current phase of the game. */
+    public void call() {
+        client.sendCall();
+    }
+
+    /** Retrieves the current phase of the game. */
+    public void fold() {
+        client.sendFold();
+    }
+
+    /**
+     * Retrieves the current phase of the game.
+     *
+     * @param amount The amount to bet. Must be a positive integer.
+     */
+    public void bet(int amount) {
+        client.sendBet(amount);
+    }
+
+    /**
+     * Retrieves the current phase of the game.
+     *
+     * @param amount The amount to raise. Must be a positive integer.
+     */
+    public void raise(int amount) {
+        client.sendRaise(amount);
+    }
+
+    /** Ensures that the game state has been initialized before accessing it. */
+    private void ensureState() {
+        if (state == null) {
+            throw new IllegalStateException("GameService used before any successful refresh()");
+        }
+    }
+
+    /**
+     * Returns the current GameState without refreshing from the server.
+     *
+     * @return The current GameState, or null if it has not been initialized yet.
+     */
+    public GameState peekStateOrNull() {
+        return state;
+    }
+}

src/main/java/ch/unibas/dmi/dbis/cs108/casono/client/game/GameState.java

@@ -0,0 +1,21 @@
+package ch.unibas.dmi.dbis.cs108.casono.client.game;
+
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * Represents the current state of the poker game, including the phase, pot size, current bet,
+ * dealer position, active player, community cards, and player information.
+ */
+public class GameState {
+    public List<Player> players = new ArrayList<>();
+    public List<Card> communityCards = new ArrayList<>();
+    public List<String> highscoreEntries = new ArrayList<>();
+
+    public String phase;
+    public int pot;
+    public int currentBet;
+    public int dealer;
+    public int activePlayer;
+    public int winnerIndex = -1;
+}

src/main/java/ch/unibas/dmi/dbis/cs108/casono/client/game/Player.java

@@ -0,0 +1,193 @@
+package ch.unibas.dmi.dbis.cs108.casono.client.game;
+
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * Represents a player in the poker game, including their name, chip count, current bet, state
+ * (e.g., "active", "folded"), and their hole cards.
+ */
+public class Player {
+
+    private PlayerId id;
+    private int chips;
+    private int bet;
+    private PlayerState state;
+
+    private List<Card> cards = new ArrayList<>();
+
+    /**
+     * Constructs a new Player with default values. The player's state is set to ACTIVE by default.
+     */
+    public Player() {
+        this.state = PlayerState.ACTIVE;
+    }
+
+    /**
+     * Constructs a new Player with the specified ID and initial chip count. The player's state is
+     * set to ACTIVE by default.
+     *
+     * @param id The unique identifier for the player.
+     * @param chips The initial number of chips the player has.
+     */
+    public Player(PlayerId id, int chips) {
+        this.id = id;
+        this.chips = chips;
+        this.bet = 0;
+        this.state = PlayerState.ACTIVE;
+    }
+
+    /**
+     * Retrieves the unique identifier of the player.
+     *
+     * @return The player's ID.
+     */
+    public PlayerId getId() {
+        return id;
+    }
+
+    /**
+     * Sets the unique identifier of the player.
+     *
+     * @param id The player's ID to set.
+     */
+    public void setId(PlayerId id) {
+        this.id = id;
+    }
+
+    /**
+     * Returns the display name of the player. If the player's ID is not set, it returns an empty
+     * string.
+     *
+     * @return The player's name.
+     */
+    public String getName() {
+        return id != null ? id.value() : "";
+    }
+
+    /**
+     * Retrieves the current chip count of the player.
+     *
+     * @return The number of chips the player has.
+     */
+    public int getChips() {
+        return chips;
+    }
+
+    /**
+     * Sets the current chip count of the player.
+     *
+     * @param chips The number of chips to set for the player.
+     */
+    public void setChips(int chips) {
+        this.chips = chips;
+    }
+
+    /**
+     * Retrieves the current bet amount of the player.
+     *
+     * @return The amount the player has currently bet in the ongoing hand.
+     */
+    public int getBet() {
+        return bet;
+    }
+
+    /**
+     * Sets the current bet amount of the player.
+     *
+     * @param bet The amount the player has currently bet in the ongoing hand to set.
+     */
+    public void setBet(int bet) {
+        this.bet = bet;
+    }
+
+    /**
+     * Retrieves the current state of the player (e.g., ACTIVE, FOLDED, ALL_IN).
+     *
+     * @return The player's current state in the game.
+     */
+    public PlayerState getState() {
+        return state;
+    }
+
+    /**
+     * Sets the current state of the player (e.g., ACTIVE, FOLDED, ALL_IN).
+     *
+     * @param state The player's current state in the game to set.
+     */
+    public void setState(PlayerState state) {
+        this.state = state;
+    }
+
+    /**
+     * Checks if the player is currently the dealer.
+     *
+     * @return True if the player's state is DEALER, false otherwise.
+     */
+    public boolean isDealer() {
+        return state == PlayerState.DEALER;
+    }
+
+    /**
+     * Retrieves the list of hole cards currently held by the player.
+     *
+     * @return A list of Card objects representing the player's hole cards.
+     */
+    public List<Card> getCards() {
+        return cards;
+    }
+
+    /**
+     * Sets the list of hole cards currently held by the player.
+     *
+     * @param cards A list of Card objects representing the player's hole cards to set.
+     */
+    public void setCards(List<Card> cards) {
+        this.cards = cards;
+    }
+
+    /**
+     * Adds a card to the player's list of hole cards.
+     *
+     * @param card The Card object to be added to the player's hole cards.
+     */
+    public void addCard(Card card) {
+        this.cards.add(card);
+    }
+
+    /**
+     * Adds the specified amount of chips to the player's current chip count.
+     *
+     * @param amount The number of chips to add to the player's current chip count.
+     */
+    public void addChips(int amount) {
+        if (amount < 0) {
+            throw new IllegalArgumentException("Amount cannot be negative");
+        }
+        this.chips += amount;
+    }
+
+    /**
+     * Removes the specified amount of chips from the player's current chip count.
+     *
+     * @param amount The number of chips to remove from the player's current chip count.
+     */
+    public void removeChips(int amount) {
+        if (amount < 0) {
+            throw new IllegalArgumentException("Amount cannot be negative");
+        }
+        if (amount > this.chips) {
+            throw new IllegalArgumentException(
+                    "Not enough chips. Available: " + this.chips + ", Requested: " + amount);
+        }
+        this.chips -= amount;
+    }
+
+    /** Sets the player's state to FOLDED, indicating that they have folded in the current hand. */
+    public void fall() {
+        this.state = PlayerState.FOLDED;
+        if (this.id != null) {
+            this.id = PlayerId.of(this.id.value() + " (Fall)");
+        }
+    }
+}

src/main/java/ch/unibas/dmi/dbis/cs108/casono/client/game/PlayerId.java

@@ -0,0 +1,66 @@
+package ch.unibas.dmi.dbis.cs108.casono.client.game;
+
+import java.util.Objects;
+
+/** Represents a unique identifier for a player in the client domain. */
+public record PlayerId(String value) {
+
+    /**
+     * Constructs a PlayerId with the given string value, ensuring it is not null or empty.
+     *
+     * @param value the string value representing the player's unique identifier.
+     */
+    public PlayerId {
+        Objects.requireNonNull(value, "PlayerId cannot be null");
+        value = value.trim();
+
+        if (value.isEmpty()) {
+            throw new IllegalArgumentException("PlayerId cannot be empty");
+        }
+    }
+
+    /** Factory method to create a PlayerId. */
+    public static PlayerId of(String value) {
+        return new PlayerId(value);
+    }
+
+    /**
+     * Returns the string representation of the PlayerId, which is the encapsulated value.
+     *
+     * @return the string value of the PlayerId.
+     */
+    @Override
+    public String toString() {
+        return value;
+    }
+
+    /**
+     * Compares this PlayerId with another object for equality.
+     *
+     * @param o the object to compare to.
+     * @return true if this PlayerId is equal to the given object, false otherwise.
+     */
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) {
+            return true;
+        }
+
+        if (o == null || getClass() != o.getClass()) {
+            return false;
+        }
+
+        PlayerId playerId = (PlayerId) o;
+        return Objects.equals(value, playerId.value);
+    }
+
+    /**
+     * Returns the hash code for this PlayerId.
+     *
+     * @return the hash code of the PlayerId.
+     */
+    @Override
+    public int hashCode() {
+        return Objects.hash(value);
+    }
+}

src/main/java/ch/unibas/dmi/dbis/cs108/casono/client/game/PlayerState.java

@@ -0,0 +1,8 @@
+package ch.unibas.dmi.dbis.cs108.casono.client.game;
+
+/** Enumeration representing the possible states of a player in the poker game. */
+public enum PlayerState {
+    ACTIVE,
+    FOLDED,
+    DEALER
+}

src/main/java/ch/unibas/dmi/dbis/cs108/casono/client/network/ChatClient.java

@@ -0,0 +1,91 @@
+package ch.unibas.dmi.dbis.cs108.casono.client.network;
+
+import ch.unibas.dmi.dbis.cs108.casono.client.chat.Message;
+import ch.unibas.dmi.dbis.cs108.casono.server.network.command.parsing.RequestParameter;
+import java.util.ArrayList;
+import java.util.List;
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+
+/**
+ * The ChatClient class is responsible for sending messages to the server and retrieving messages
+ * from the server. It uses the ClientService to send commands and receive responses from the
+ * server.
+ */
+public class ChatClient {
+
+    private final ClientService clientService;
+    private final Logger logger;
+
+    /**
+     * Constructs a ChatClient with the given ClientService for communication.
+     *
+     * @param clientService The ClientService instance used to send commands and receive responses
+     *     from the server.
+     */
+    public ChatClient(ClientService clientService) {
+        this.clientService = clientService;
+        this.logger = LogManager.getLogger(ChatClient.class);
+    }
+
+    /**
+     * Send a Message to the server by converting it to a string format and sending a "SEND_MESSAGE"
+     * command with the message content as arguments.
+     *
+     * @param message The Message object to be sent to the server.
+     */
+    public void sendMessage(Message message) {
+        String request = "SEND_MESSAGE " + message.toArgsString();
+        logger.info("Writing to server: " + request);
+        clientService.processCommand(request);
+    }
+
+    /**
+     * Retrieve messages from the server by first sending a "GET_MESSAGE_COUNT" command to determine
+     * how many messages are available and then sending "GET_NEXT_MESSAGE" commands in a loop to
+     * retrieve each message. The retrieved messages are parsed into Message objects and returned as
+     * a list.
+     *
+     * @return A list of Message objects representing the messages retrieved from the server.
+     */
+    public List<Message> getMessages() {
+        logger.info("Asking server for new messages");
+        List<RequestParameter> countStr =
+                ClientService.convertToRequestParameters(
+                        clientService.processCommand("GET_MESSAGE_COUNT"));
+        RequestParameter countRes = countStr.getFirst();
+        if (!countRes.key().equals("COUNT")) {
+            logger.error("Not the right response from server");
+        }
+        int count = Integer.parseInt(countRes.value());
+        logger.info("Got " + count + " messages");
+        ArrayList<Message> messages = new ArrayList<>();
+        for (int i = 0; i < count; i++) {
+            List<RequestParameter> msgRes =
+                    ClientService.convertToRequestParameters(
+                            clientService.processCommand("GET_NEXT_MESSAGE"));
+            Message msg = Message.toMessageReqPars(msgRes);
+            messages.add(msg);
+        }
+        return messages;
+    }
+
+    /**
+     * Method to poll the usernames of all users currently connected to the server, by sending the
+     * "LIST_USERS" command.
+     *
+     * @return List of all usernames retrieved from the server.
+     */
+    public List<String> getUsers() {
+        logger.info("Asking server for list of users");
+        List<String> users = clientService.processCommand("LIST_USERS");
+        List<String> parameters = new ArrayList<>();
+        for (String line : users) {
+            String trimmed = line == null ? "" : line.trim();
+            if (trimmed.startsWith("USERNAME=")) {
+                parameters.add(trimmed);
+            }
+        }
+        return parameters;
+    }
+}

src/main/java/ch/unibas/dmi/dbis/cs108/casono/client/network/ClientService.java

@@ -0,0 +1,433 @@
+package ch.unibas.dmi.dbis.cs108.casono.client.network;
+
+import ch.unibas.dmi.dbis.cs108.casono.server.network.command.parsing.RequestParameter;
+import ch.unibas.dmi.dbis.cs108.casono.server.network.transport.RawPacket;
+import ch.unibas.dmi.dbis.cs108.casono.server.network.transport.TcpTransport;
+import java.io.IOException;
+import java.net.Socket;
+import java.util.ArrayDeque;
+import java.util.ArrayList;
+import java.util.Deque;
+import java.util.List;
+import java.util.Map;
+import java.util.concurrent.ArrayBlockingQueue;
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.CopyOnWriteArrayList;
+import java.util.concurrent.ExecutionException;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+import java.util.concurrent.Future;
+import java.util.concurrent.atomic.AtomicBoolean;
+import java.util.concurrent.atomic.AtomicInteger;
+import java.util.function.Consumer;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+
+/**
+ * The ClientService class is responsible for managing the connection to the server, sending
+ * commands, and receiving responses. It uses a TcpTransport to communicate with the server and an
+ * ExecutorService to handle asynchronous requests.
+ */
+public class ClientService {
+
+    private final TcpTransport clienttcptransport;
+    private final Socket socket;
+
+    private final ExecutorService executor;
+    private final boolean offlineMode;
+
+    private final AtomicInteger idGenerator;
+    private Logger logger;
+
+    private final Map<Integer, ArrayBlockingQueue<ParsedResponse>> pendingResponses =
+            new ConcurrentHashMap<>();
+    private final CopyOnWriteArrayList<Consumer<List<String>>> eventListeners =
+            new CopyOnWriteArrayList<>();
+    private Thread readerThread = null;
+    private final AtomicBoolean running = new AtomicBoolean(false);
+    private static final int READER_JOIN_TIMEOUT_MS = 500;
+
+    /**
+     * Constructs a ClientService with the given server IP and port. It establishes a socket
+     * connection to the server and initializes the TcpTransport and ExecutorService for
+     * communication.
+     *
+     * @param ip The IP address of the server to connect to.
+     * @param port The port number of the server to connect to.
+     */
+    public ClientService(String ip, int port) {
+        this.idGenerator = new AtomicInteger(0);
+
+        this.logger = LogManager.getLogger(ClientService.class);
+
+        this.offlineMode = false;
+
+        try {
+            socket = new Socket(ip, port);
+            clienttcptransport = new TcpTransport(socket);
+            logger.info("Connected to server at " + ip);
+        } catch (IOException i) {
+            throw new RuntimeException(i);
+        }
+
+        executor = Executors.newSingleThreadExecutor();
+
+        startReaderThread();
+    }
+
+    private void startReaderThread() {
+        running.set(true);
+        readerThread =
+                new Thread(
+                        () -> {
+                            while (running.get()) {
+                                try {
+                                    RawPacket rp = clienttcptransport.read();
+                                    processRawPacket(rp);
+                                } catch (IOException e) {
+                                    if (running.get()) {
+                                        logger.warn("IO error on transport reader", e);
+                                    }
+                                    break;
+                                } catch (InterruptedException e) {
+                                    Thread.currentThread().interrupt();
+                                    break;
+                                }
+                            }
+                        },
+                        "casono-client-reader");
+        readerThread.setDaemon(true);
+        readerThread.start();
+    }
+
+    private void processRawPacket(RawPacket rp) throws InterruptedException, IOException {
+        int rid = rp.requestId();
+        String responseText = rp.payload();
+        logger.info("Raw message '{}'", responseText);
+
+        ParsedPacket parsed = parsePacketContent(responseText);
+
+        logger.debug(
+                "Parsed response lines (rid={}, success={}, openBlocks={}): {}",
+                rid,
+                parsed.success,
+                parsed.blockStack.size(),
+                parsed.lines);
+
+        handleParsedResponse(rid, parsed.success, parsed.lines);
+    }
+
+    private ParsedPacket parsePacketContent(String responseText) {
+        boolean hasStatus = false;
+        boolean success = false;
+        List<String> lines = new ArrayList<>();
+        Deque<String> blockStack = new ArrayDeque<>();
+
+        for (String rawLine : responseText.split("\\n")) {
+            String line = rawLine;
+            String trimmed = line.trim();
+
+            if (!hasStatus) {
+                StatusCheckResult status = checkStatus(trimmed);
+                if (status != null) {
+                    success = status.success;
+                    hasStatus = true;
+                }
+                continue;
+            }
+
+            if (trimmed.isEmpty()) {
+                continue;
+            }
+
+            line = line.replaceFirst("^\\s+", "");
+            trimmed = line.trim();
+
+            if (isContainerStart(trimmed)) {
+                blockStack.push(trimmed);
+                lines.add(trimmed);
+                continue;
+            }
+
+            if ("END".equals(trimmed)) {
+                if (!blockStack.isEmpty()) {
+                    blockStack.pop();
+                    lines.add("END");
+                    continue;
+                }
+                break;
+            }
+
+            lines.add(line);
+        }
+
+        if (!hasStatus) {
+            success = inferStatus(responseText);
+        }
+
+        return new ParsedPacket(success, lines, blockStack);
+    }
+
+    private StatusCheckResult checkStatus(String trimmed) {
+        if ("+OK".equals(trimmed)) {
+            return new StatusCheckResult(true);
+        }
+        if (trimmed.startsWith("-ERR") || trimmed.startsWith("-ERROR")) {
+            return new StatusCheckResult(false);
+        }
+        return null;
+    }
+
+    private boolean inferStatus(String responseText) {
+        if (responseText.contains("+OK")) {
+            return true;
+        }
+        if (responseText.contains("-ERR") || responseText.contains("-ERROR")) {
+            return false;
+        }
+        return true;
+    }
+
+    private void handleParsedResponse(int rid, boolean success, List<String> lines)
+            throws InterruptedException {
+        if (rid == 0) {
+            for (Consumer<List<String>> l : eventListeners) {
+                try {
+                    l.accept(List.copyOf(lines));
+                } catch (Exception e) {
+                    logger.warn("Event listener threw", e);
+                }
+            }
+        } else {
+            ArrayBlockingQueue<ParsedResponse> q = pendingResponses.get(rid);
+            if (q != null) {
+                q.put(new ParsedResponse(success, lines));
+            } else {
+                logger.warn("No pending response queue for id {}", rid);
+            }
+        }
+    }
+
+    private record ParsedPacket(boolean success, List<String> lines, Deque<String> blockStack) {}
+
+    private record StatusCheckResult(boolean success) {}
+
+    private boolean isContainerStart(String token) {
+        return token.equals("LOBBIES")
+                || token.equals("LOBBY")
+                || token.equals("PLAYERS")
+                || token.equals("PLAYER")
+                || token.equals("USERS")
+                || token.equals("USER")
+                || token.equals("CARDS")
+                || token.equals("CARD");
+    }
+
+    /**
+     * Constructs a ClientService in offline mode. No network connection will be attempted and calls
+     * to processCommand will throw a RuntimeException.
+     *
+     * @param offline true to create an offline (no-network) client service
+     */
+    public ClientService(boolean offline) {
+        this.idGenerator = new AtomicInteger(0);
+        this.offlineMode = offline;
+        this.socket = null;
+        this.clienttcptransport = null;
+        this.executor = Executors.newSingleThreadExecutor();
+    }
+
+    /** Returns true if this ClientService is running in offline mode (no network). */
+    public boolean isOffline() {
+        return offlineMode;
+    }
+
+    // Allow primitive values to contain hyphens (UUIDs) in addition to
+    // digits/words/colons
+    static Pattern responseRex =
+            Pattern.compile(
+                    "(?<key>\\w+)=(('(?<string>([^']|\\')+)')|(?<primVal>[+-]?[-\\d\\w:]+))");
+
+    /**
+     * Removes escape characters from a string, specifically converting escaped single quotes (\')
+     * back to regular single quotes (').
+     *
+     * @param input The escaped string to process.
+     * @return The unescaped string.
+     */
+    private static String unescape(String input) {
+        return input.replaceAll("\\\\'", "'");
+    }
+
+    /**
+     * Converts a list of raw string parameters into a list of {@link RequestParameter} objects. It
+     * uses a regex matcher to distinguish between quoted strings (which are unescaped) and
+     * primitive values.
+     *
+     * @param input A list of raw strings to be parsed.
+     * @return A list of parsed {@link RequestParameter} objects.
+     * @throws RuntimeException if a parameter does not match the expected format.
+     */
+    public static List<RequestParameter> convertToRequestParameters(List<String> input) {
+        return input.stream()
+                .map((String parString) -> responseRex.matcher(parString))
+                .filter(Matcher::matches)
+                .map(
+                        (m) -> {
+                            if (!(m.group("string") == null)) {
+                                return new RequestParameter(
+                                        m.group("key"), unescape(m.group("string")));
+                            } else if (!(m.group("primVal") == null)) {
+                                return new RequestParameter(m.group("key"), m.group("primVal"));
+                            } else {
+                                throw new RuntimeException();
+                            }
+                        })
+                .toList();
+    }
+
+    private static record ParsedResponse(boolean success, List<String> lines) {}
+
+    /**
+     * Register an event listener that receives unsolicited event payload lines (no status prefix).
+     */
+    public void addEventListener(Consumer<List<String>> listener) {
+        eventListeners.add(listener);
+    }
+
+    public void removeEventListener(Consumer<List<String>> listener) {
+        eventListeners.remove(listener);
+    }
+
+    /**
+     * Sends a command to the server and processes the multi-line response. It handles the protocol
+     * handshake (expecting +OK), strips leading tabs from response lines, and collects them until
+     * the "END" marker is reached.
+     *
+     * @param message The raw command string to be sent to the transport layer.
+     * @return A list of response lines received from the server (excluding protocol markers).
+     * @throws RuntimeException if the server responds with an error or if a communication failure
+     *     occurs.
+     */
+    protected List<String> processCommand(String message) {
+        if (offlineMode) {
+            throw new RuntimeException("ClientService is offline");
+        }
+
+        int reqId = idGenerator.incrementAndGet();
+        ArrayBlockingQueue<ParsedResponse> q = new ArrayBlockingQueue<>(1);
+        pendingResponses.put(reqId, q);
+
+        Future<?> writeFuture =
+                executor.submit(
+                        () -> {
+                            try {
+                                clienttcptransport.write(new RawPacket(reqId, message));
+                            } catch (IOException e) {
+                                throw new RuntimeException(e);
+                            }
+                        });
+
+        try {
+            writeFuture.get();
+        } catch (InterruptedException e) {
+            Thread.currentThread().interrupt();
+            pendingResponses.remove(reqId);
+            throw new RuntimeException(e);
+        } catch (ExecutionException e) {
+            pendingResponses.remove(reqId);
+            throw getRuntimeException(e);
+        }
+
+        ParsedResponse pr;
+        try {
+            pr = q.take();
+        } catch (InterruptedException e) {
+            Thread.currentThread().interrupt();
+            pendingResponses.remove(reqId);
+            throw new RuntimeException(e);
+        } finally {
+            pendingResponses.remove(reqId);
+        }
+
+        if (pr.success) {
+            return pr.lines;
+        }
+
+        throw new RuntimeException("Error in " + message + ": " + pr.lines);
+    }
+
+    /**
+     * Helper method to send a request to the server using the ExecutorService. It submits the
+     * request as a Runnable task and waits for its completion. If the task is interrupted or
+     * encounters an execution exception, it throws a RuntimeException with the appropriate cause.
+     *
+     * @param request The Runnable task representing the request to be sent to the server.
+     */
+    private void sendRequest(Runnable request) {
+        Future<?> future = executor.submit(request);
+        try {
+            future.get();
+        } catch (InterruptedException e) {
+            throw new RuntimeException(e);
+        } catch (ExecutionException e) {
+            throw getRuntimeException(e);
+        }
+    }
+
+    /**
+     * Helper method to extract the cause of an exception and return it as a RuntimeException. If
+     * the cause is null, it returns the original exception as a RuntimeException. If the cause is
+     * already a RuntimeException, it returns it directly. Otherwise, it wraps the cause in a new
+     * RuntimeException and returns it.
+     *
+     * @param e The exception from which to extract the cause.
+     * @return A RuntimeException representing the cause of the original exception.
+     */
+    private static RuntimeException getRuntimeException(Exception e) {
+        Throwable cause = e.getCause();
+        if (cause == null) {
+            return e instanceof RuntimeException ? (RuntimeException) e : new RuntimeException(e);
+        }
+        if (cause instanceof RuntimeException) {
+            return (RuntimeException) cause;
+        }
+        return new RuntimeException(cause);
+    }
+
+    /**
+     * Closes the socket connection to the server and shuts down the ExecutorService. It also closes
+     * the TcpTransport used for communication. If any IOException occurs during this process, it
+     * prints the exception to the console.
+     */
+    public void closeSocket() {
+        try {
+            running.set(false);
+            if (readerThread != null) {
+                readerThread.interrupt();
+                try {
+                    readerThread.join(READER_JOIN_TIMEOUT_MS);
+                } catch (InterruptedException ignored) {
+                    Thread.currentThread().interrupt();
+                }
+            }
+
+            executor.shutdownNow();
+            clienttcptransport.close();
+            socket.close();
+            logger.info("Socket closed");
+        } catch (IOException j) {
+            logger.debug(j);
+        }
+    }
+
+    // removed unused helper writeToTransport; write is done via processCommand()
+    // which
+    // manages request ids and response matching
+
+    public void ping() {
+        processCommand("PING");
+    }
+}

src/main/java/ch/unibas/dmi/dbis/cs108/casono/client/network/CoreClient.java

@@ -0,0 +1,37 @@
+package ch.unibas.dmi.dbis.cs108.casono.client.network;
+
+/**
+ * The CoreClient class provides basic functionalities for communicating with the server, such as
+ * sending a ping command to check connectivity and logging in with a username. It uses the
+ * ClientService to send commands and receive responses from the server.
+ */
+public class CoreClient {
+    private final ClientService clientService;
+
+    /**
+     * Constructs a CoreClient with the given ClientService for communication.
+     *
+     * @param clientservice The ClientService instance used to send commands and receive responses
+     *     from the server.
+     */
+    public CoreClient(ClientService clientservice) {
+        this.clientService = clientservice;
+    }
+
+    /**
+     * Sends a "PING" command to the server to check connectivity. The server should respond with a
+     * "PONG" message if the connection is successful.
+     */
+    public void ping() {
+        clientService.processCommand("PING");
+    }
+
+    /**
+     * Logs in to the server with the given username by sending a "LOGIN" command.
+     *
+     * @param user The username to log in with.
+     */
+    public void login(String user) {
+        clientService.processCommand("LOGIN USERNAME=" + user);
+    }
+}

src/main/java/ch/unibas/dmi/dbis/cs108/casono/client/network/GameClient.java

@@ -0,0 +1,285 @@
+package ch.unibas.dmi.dbis.cs108.casono.client.network;
+
+import ch.unibas.dmi.dbis.cs108.casono.client.game.Card;
+import ch.unibas.dmi.dbis.cs108.casono.client.game.GameState;
+import ch.unibas.dmi.dbis.cs108.casono.client.game.Player;
+import ch.unibas.dmi.dbis.cs108.casono.client.game.PlayerId;
+import ch.unibas.dmi.dbis.cs108.casono.client.game.PlayerState;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.logging.Level;
+import java.util.logging.Logger;
+
+/**
+ * Fetches and parses game state from server.
+ *
+ * <p>Protocol notes (based on your current server implementation): - Success replies contain:
+ * PHASE, POT, CURRENT_BET, DEALER, ACTIVE_PLAYER, then blocks: - CARD ... END (community cards on
+ * root level) - PLAYER ... (NAME/CHIPS/BET/STATE + optional CARD blocks for requesting player) ...
+ * END - Error replies contain: -ERR then CODE=..., MSG=..., END
+ *
+ * <p>Important: - The server does NOT wrap cards in a "CARDS" container. - CARD blocks appear
+ * either: - at root level -> community cards - inside PLAYER -> hole cards for that player (usually
+ * only for the requesting user)
+ */
+public class GameClient {
+
+    private static final Logger LOG = Logger.getLogger(GameClient.class.getName());
+
+    private final ClientService client;
+    private final int gameId;
+
+    public GameClient(ClientService client, int gameId) {
+        if (client == null) {
+            throw new IllegalArgumentException("ClientService must not be null");
+        }
+
+        this.client = client;
+        this.gameId = gameId;
+        LOG.info(() -> "GameClient initialized for gameId=" + gameId);
+    }
+
+    public GameState fetchGameState() {
+        final String cmd = "GET_GAME_STATE GAME_ID=" + gameId;
+
+        List<String> lines;
+        try {
+            lines = client.processCommand(cmd);
+        } catch (Exception e) {
+            LOG.log(Level.SEVERE, "processCommand failed for " + cmd + ": " + e.getMessage(), e);
+            return null;
+        }
+
+        if (lines == null || lines.isEmpty()) {
+            LOG.warning("Empty server response for " + cmd);
+            return null;
+        }
+
+        LOG.info(() -> "GET_GAME_STATE raw lines count=" + lines.size() + " lines=" + lines);
+
+        String joined = String.join("\n", lines);
+
+        if (joined.contains("-ERR") || joined.contains("-ERROR")) {
+            String code = extractValue(joined, "CODE");
+            String msg = extractValue(joined, "MSG");
+            LOG.info(() -> "GET_GAME_STATE returned -ERR code=" + code + " msg=" + msg);
+
+            if ("GAME_NOT_STARTED".equalsIgnoreCase(code)) {
+                return null;
+            }
+            return null;
+        }
+
+        try {
+            GameState state = parseGameState(joined);
+            LOG.info(
+                    () ->
+                            "Parsed state: phase="
+                                    + state.phase
+                                    + " pot="
+                                    + state.pot
+                                    + " players="
+                                    + (state.players != null ? state.players.size() : 0)
+                                    + " community="
+                                    + (state.communityCards != null
+                                            ? state.communityCards.size()
+                                            : 0));
+            return state;
+        } catch (Exception e) {
+            LOG.log(Level.SEVERE, "Failed parsing game state. Payload=\n" + joined, e);
+            return null;
+        }
+    }
+
+    public void sendCall() {
+        client.processCommand("CALL GAME_ID=" + gameId);
+    }
+
+    public void sendFold() {
+        client.processCommand("FOLD GAME_ID=" + gameId);
+    }
+
+    public void sendBet(int amount) {
+        client.processCommand("BET GAME_ID=" + gameId + " AMOUNT=" + amount);
+    }
+
+    public void sendRaise(int amount) {
+        client.processCommand("RAISE GAME_ID=" + gameId + " AMOUNT=" + amount);
+    }
+
+    private GameState parseGameState(String input) {
+        GameState s = new GameState();
+        s.players = new ArrayList<>();
+        s.communityCards = new ArrayList<>();
+
+        ParseState state = new ParseState();
+        for (String raw : input.split("\n")) {
+            String line = raw.trim();
+            if (line.isEmpty() || line.startsWith("+OK")) {
+                continue;
+            }
+
+            if (!parseGlobalField(s, line)
+                    && !parsePlayerStructure(s, state, line)
+                    && !parseCardData(state, line)
+                    && !parsePlayerData(state, line)) {
+                LOG.fine(() -> "Ignored line: '" + line + "'");
+            }
+        }
+        return s;
+    }
+
+    private boolean parseGlobalField(GameState s, String line) {
+        return switch (line) {
+            case String l when l.startsWith("PHASE=") -> {
+                s.phase = value(l);
+                yield true;
+            }
+            case String l when l.startsWith("POT=") -> {
+                s.pot = intVal(l);
+                yield true;
+            }
+            case String l when l.startsWith("CURRENT_BET=") -> {
+                s.currentBet = intVal(l);
+                yield true;
+            }
+            case String l when l.startsWith("DEALER=") -> {
+                s.dealer = intVal(l);
+                yield true;
+            }
+            case String l when l.startsWith("ACTIVE_PLAYER=") -> {
+                s.activePlayer = intVal(l);
+                yield true;
+            }
+            case String l when l.startsWith("WINNER=") -> {
+                s.winnerIndex = intVal(l);
+                yield true;
+            }
+            case String l when l.startsWith("HIGHSCORE=") -> {
+                s.highscoreEntries.add(value(l));
+                yield true;
+            }
+            default -> false;
+        };
+    }
+
+    private boolean parsePlayerStructure(GameState s, ParseState state, String line) {
+        if (line.equals("PLAYER")) {
+            state.currentPlayer = new Player();
+            s.players.add(state.currentPlayer);
+            state.currentCard = null;
+            state.insidePlayer = true;
+            return true;
+        }
+
+        if (line.equals("CARDS")) {
+            return true;
+        }
+
+        if (line.equals("CARD")) {
+            state.currentCard = new Card("", "");
+            if (state.insidePlayer && state.currentPlayer != null) {
+                state.currentPlayer.addCard(state.currentCard);
+            } else {
+                s.communityCards.add(state.currentCard);
+            }
+            return true;
+        }
+
+        if (line.equals("END")) {
+            if (state.currentCard != null) {
+                state.currentCard = null;
+            } else if (state.insidePlayer) {
+                state.insidePlayer = false;
+                state.currentPlayer = null;
+            }
+            return true;
+        }
+        return false;
+    }
+
+    private boolean parseCardData(ParseState state, String line) {
+        if (state.currentCard == null) {
+            return false;
+        }
+
+        if (line.startsWith("VALUE=")) {
+            state.currentCard.setValue(value(line));
+            return true;
+        }
+        if (line.startsWith("SUIT=")) {
+            state.currentCard.setSuit(value(line));
+            return true;
+        }
+        return false;
+    }
+
+    private boolean parsePlayerData(ParseState state, String line) {
+        if (state.currentPlayer == null) {
+            return false;
+        }
+
+        if (line.startsWith("USERNAME=") || line.startsWith("NAME=")) {
+            state.currentPlayer.setId(PlayerId.of(value(line)));
+            return true;
+        }
+
+        if (line.startsWith("CHIPS=")) {
+            state.currentPlayer.setChips(intVal(line));
+            return true;
+        }
+
+        if (line.startsWith("BET=")) {
+            state.currentPlayer.setBet(intVal(line));
+            return true;
+        }
+
+        if (line.startsWith("STATE=")) {
+            state.currentPlayer.setState(parseState(value(line)));
+            return true;
+        }
+
+        return false;
+    }
+
+    private static class ParseState {
+        Player currentPlayer;
+        Card currentCard;
+        boolean insidePlayer;
+    }
+
+    private static String value(String line) {
+        return line.split("=", 2)[1];
+    }
+
+    private static int intVal(String line) {
+        return Integer.parseInt(value(line));
+    }
+
+    private static PlayerState parseState(String s) {
+        if (s == null) {
+            return PlayerState.ACTIVE;
+        }
+
+        return switch (s.trim().toUpperCase()) {
+            case "ACTIVE" -> PlayerState.ACTIVE;
+            case "FOLDED" -> PlayerState.FOLDED;
+            case "DEALER" -> PlayerState.DEALER;
+            default -> PlayerState.ACTIVE;
+        };
+    }
+
+    private static String extractValue(String joined, String key) {
+        if (joined == null) {
+            return null;
+        }
+
+        for (String raw : joined.split("\n")) {
+            String line = raw.trim();
+            if (line.startsWith(key + "=")) {
+                return line.substring((key + "=").length()).replace("'", "");
+            }
+        }
+        return null;
+    }
+}

src/main/java/ch/unibas/dmi/dbis/cs108/casono/client/network/LobbyClient.java

@@ -0,0 +1,259 @@
+package ch.unibas.dmi.dbis.cs108.casono.client.network;
+
+import ch.unibas.dmi.dbis.cs108.casono.server.network.command.parsing.RequestParameter;
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * The LobbyClient class is responsible for communicating with the server to manage game lobbies. It
+ * provides methods to create a lobby, join a lobby, and fetch the current status of a lobby by
+ * sending appropriate commands to the server and processing the responses.
+ */
+public class LobbyClient {
+    private final ClientService client;
+
+    /**
+     * Constructs a LobbyClient with the given ClientService for communication.
+     *
+     * @param client The ClientService instance used to send commands and receive responses from the
+     *     server.
+     */
+    public LobbyClient(ClientService client) {
+        this.client = client;
+    }
+
+    public ClientService getClientService() {
+        return client;
+    }
+
+    /**
+     * Fetch the current status of the lobby with the given id from the server.
+     *
+     * @param lobbyId The id of the lobby to fetch the status for.
+     * @return A string representing the current status of the lobby, as returned by the server.
+     */
+    public String fetchLobbyStatusString(int lobbyId) {
+        List<String> lines = client.processCommand("GET_LOBBY_STATUS ID=" + lobbyId);
+
+        // Prefer explicit STATUS parameter when available
+        List<RequestParameter> params = ClientService.convertToRequestParameters(lines);
+        for (RequestParameter p : params) {
+            if ("STATUS".equalsIgnoreCase(p.key())) {
+                return p.value();
+            }
+        }
+
+        // Fallback: some servers may return a plain token as the first line
+        if (!lines.isEmpty()) {
+            String first = lines.get(0).trim();
+            if ("CREATED".equalsIgnoreCase(first) || "RUNNING".equalsIgnoreCase(first)) {
+                return first.toUpperCase();
+            }
+        }
+
+        return null;
+    }
+
+    /**
+     * Request the server to create a new lobby and return the id of the newly created lobby.
+     *
+     * @return The id of the newly created lobby, as returned by the server.
+     */
+    public int createLobby() {
+        List<String> lines = client.processCommand("CREATE_LOBBY");
+
+        List<RequestParameter> params = ClientService.convertToRequestParameters(lines);
+        for (RequestParameter p : params) {
+            if ("LOBBY_ID".equalsIgnoreCase(p.key())) {
+                return Integer.parseInt(p.value());
+            }
+        }
+
+        // Fallback for simple legacy/test servers that return the id as a single plain
+        // line
+        if (!lines.isEmpty()) {
+            try {
+                return Integer.parseInt(lines.get(0));
+            } catch (NumberFormatException ignored) {
+            }
+        }
+
+        throw new RuntimeException("No LOBBY_ID in response: " + lines);
+    }
+
+    /** Fetches the global highscores from the server. */
+    public List<String> getHighscores() {
+        List<String> lines = client.processCommand("GET_HIGHSCORES");
+        List<RequestParameter> params = ClientService.convertToRequestParameters(lines);
+
+        List<String> entries = new ArrayList<>();
+        for (RequestParameter p : params) {
+            if ("HIGHSCORE".equalsIgnoreCase(p.key())) {
+                entries.add(p.value());
+            }
+        }
+
+        return entries;
+    }
+
+    /** Clears all global highscores on the server. */
+    public void clearHighscores() {
+        client.processCommand("CLEAR_HIGHSCORES");
+    }
+
+    /**
+     * Request the server to return the id of the lobby that the client is currently in.
+     *
+     * @return The id of the lobby that the client is currently in, as returned by the server.
+     */
+    public int getLobbyId() {
+        List<String> lines = client.processCommand("GET_LOBBY_ID");
+        if (lines.isEmpty()) {
+            throw new RuntimeException("GET_LOBBY_ID returned empty response");
+        }
+        try {
+            return Integer.parseInt(lines.get(0).trim());
+        } catch (NumberFormatException e) {
+            throw new RuntimeException("Invalid GET_LOBBY_ID response: " + lines, e);
+        }
+    }
+
+    /**
+     * Request the server to join the lobby with the given id.
+     *
+     * @param lobbyId The id of the lobby to join.
+     */
+    public void joinLobby(int lobbyId) {
+        client.processCommand("JOIN_LOBBY ID=" + lobbyId);
+    }
+
+    /**
+     * Logs in to the server with the given username by sending a "LOGIN" command.
+     *
+     * @param user The username to log in with.
+     * @return a {@link LoginResult} containing the assigned username and id as returned by the
+     *     server
+     */
+    public LoginResult login(String user) {
+        String command = buildLoginCommand(user);
+        List<String> lines = client.processCommand(command);
+
+        List<RequestParameter> params = ClientService.convertToRequestParameters(lines);
+
+        String assigned = user;
+        String id = null;
+        for (RequestParameter p : params) {
+            if ("USERNAME".equalsIgnoreCase(p.key())) {
+                assigned = p.value();
+            } else if ("ID".equalsIgnoreCase(p.key())) {
+                id = p.value();
+            }
+        }
+        return new LoginResult(assigned, id);
+    }
+
+    private String buildLoginCommand(String username) {
+        if (username == null || username.isBlank()) {
+            return "LOGIN";
+        }
+        return "LOGIN USERNAME=" + username.trim();
+    }
+
+    /**
+     * Changes the username for the currently logged-in session.
+     *
+     * @param newUsername desired new username
+     * @return a {@link LoginResult} containing assigned username and id as returned by the server
+     */
+    public LoginResult changeUsername(String newUsername) {
+        List<String> lines = client.processCommand("CHANGE_USERNAME USERNAME=" + newUsername);
+
+        List<RequestParameter> params = ClientService.convertToRequestParameters(lines);
+
+        String assigned = newUsername;
+        String id = null;
+        for (RequestParameter p : params) {
+            if ("USERNAME".equalsIgnoreCase(p.key())) {
+                assigned = p.value();
+            } else if ("ID".equalsIgnoreCase(p.key())) {
+                id = p.value();
+            }
+        }
+        return new LoginResult(assigned, id);
+    }
+
+    /**
+     * Request the server for the list of available lobbies.
+     *
+     * @return list of LobbyInfo objects representing current lobbies
+     */
+    public List<LobbyInfo> getLobbyList() {
+        List<String> lines = client.processCommand("GET_LOBBY_LIST");
+
+        List<RequestParameter> params = ClientService.convertToRequestParameters(lines);
+
+        List<LobbyInfo> result = new ArrayList<>();
+
+        Integer currentId = null;
+        String currentName = null;
+        Integer currentPlayerCount = null;
+
+        for (RequestParameter p : params) {
+            String key = p.key().toUpperCase();
+            String val = p.value();
+            switch (key) {
+                case "ID":
+                    if (currentId != null) {
+                        result.add(
+                                new LobbyInfo(
+                                        currentId,
+                                        currentName,
+                                        currentPlayerCount == null ? 0 : currentPlayerCount));
+                        currentName = null;
+                        currentPlayerCount = null;
+                    }
+                    try {
+                        currentId = Integer.parseInt(val);
+                    } catch (NumberFormatException e) {
+                        currentId = null;
+                    }
+                    break;
+                case "NAME":
+                    currentName = val;
+                    break;
+                case "PLAYER_COUNT":
+                    try {
+                        currentPlayerCount = Integer.parseInt(val);
+                    } catch (NumberFormatException e) {
+                        currentPlayerCount = 0;
+                    }
+                    break;
+                default:
+                    break;
+            }
+        }
+
+        if (currentId != null) {
+            result.add(
+                    new LobbyInfo(
+                            currentId,
+                            currentName,
+                            currentPlayerCount == null ? 0 : currentPlayerCount));
+        }
+
+        return result;
+    }
+
+    /** Simple data holder for lobby metadata returned by the server. */
+    public static final class LobbyInfo {
+        public final int id;
+        public final String name;
+        public final int playerCount;
+
+        public LobbyInfo(int id, String name, int playerCount) {
+            this.id = id;
+            this.name = name;
+            this.playerCount = playerCount;
+        }
+    }
+}

src/main/java/ch/unibas/dmi/dbis/cs108/casono/client/network/LoginResult.java

@@ -0,0 +1,38 @@
+package ch.unibas.dmi.dbis.cs108.casono.client.network;
+
+/**
+ * Result of a successful login request.
+ *
+ * <p>Holds the username assigned by the server and the server-side id as a string (UUID). The
+ * client previously attempted to parse the id as an integer which failed when the server returned a
+ * UUID; this class therefore stores the id as a {@link String}.
+ */
+public class LoginResult {
+    private final String username;
+    private final String id;
+
+    /**
+     * Create a login result.
+     *
+     * @param username the assigned username
+     * @param id the assigned id (UUID string) returned by the server
+     */
+    public LoginResult(String username, String id) {
+        this.username = username;
+        this.id = id;
+    }
+
+    /**
+     * @return the assigned username
+     */
+    public String getUsername() {
+        return username;
+    }
+
+    /**
+     * @return the assigned id as returned by the server (UUID string)
+     */
+    public String getId() {
+        return id;
+    }
+}

src/main/java/ch/unibas/dmi/dbis/cs108/casono/client/ui/chatui/ChatBoxController.java

@@ -0,0 +1,270 @@
+package ch.unibas.dmi.dbis.cs108.casono.client.ui.chatui;
+
+import ch.unibas.dmi.dbis.cs108.casono.client.chat.ChatController;
+import ch.unibas.dmi.dbis.cs108.casono.client.chat.ChatModel;
+import ch.unibas.dmi.dbis.cs108.casono.client.chat.ChatType;
+import ch.unibas.dmi.dbis.cs108.casono.client.chat.Message;
+import java.io.IOException;
+import java.net.URL;
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.concurrent.Callable;
+import java.util.concurrent.CompletableFuture;
+import javafx.application.Platform;
+import javafx.fxml.FXML;
+import javafx.fxml.FXMLLoader;
+import javafx.scene.Node;
+import javafx.scene.control.MenuButton;
+import javafx.scene.control.MenuItem;
+import javafx.scene.control.Tab;
+import javafx.scene.control.TabPane;
+import javafx.scene.layout.HBox;
+import javafx.scene.layout.Priority;
+import javafx.scene.layout.VBox;
+
+public class ChatBoxController {
+
+    private String username;
+
+    private final ChatController chatController;
+
+    @FXML private VBox chatBox;
+
+    @FXML private TabPane chatTabPane;
+
+    @FXML private MenuButton addWhisperChatButton;
+
+    @FXML private HBox menuBox;
+
+    private FXMLLoader fxmlLoader;
+
+    private final List<String> activeWhisperChats;
+
+    @FXML private final Map<String, Tab> usernameTabMap;
+
+    /**
+     * Constructor for the ChatBoxController, initializes the necessary fields and data structures
+     * for managing chat tabs and whisper chats.
+     *
+     * @param username The username of the current user.
+     * @param chatController The ChatController instance responsible for handling chat logic and
+     *     communication with the server.
+     */
+    public ChatBoxController(String username, ChatController chatController) {
+        this.username = username;
+        this.chatController = chatController;
+        activeWhisperChats = new ArrayList<>();
+        usernameTabMap = new HashMap<>();
+    }
+
+    public void setUsername(String username) {
+        if (username != null && !username.isBlank()) {
+            this.username = username.trim();
+        }
+    }
+
+    /**
+     * Initializes the chat interface by creating the global chat model and adding the corresponding
+     * "GLOBAL" tab to the interface. It also registers the global chat in the {@link
+     * ChatController}'s model map.
+     */
+    @FXML
+    public void initialize() {
+        ChatType global = ChatType.GLOBAL;
+        ChatModel globalChatModel = new ChatModel(global, username, -1, null);
+        chatController.getChatModelMap().put(new ChatController.ChatKey(global), globalChatModel);
+        addChatTab("GLOBAL", globalChatModel, global);
+        addWhisperChatButton.setOnAction(event -> addWhisperChatButton.show());
+    }
+
+    /**
+     * Adds a specific user to the list of available whisper targets. Creates a new menu item for
+     * the user and defines the action to open a private chat tab when selected.
+     *
+     * @param targetUserName The username of the person to be added to the whisper list.
+     */
+    public void addWhisperUser(String targetUserName) {
+        Platform.runLater(
+                () -> {
+                    for (MenuItem existing : addWhisperChatButton.getItems()) {
+                        if (targetUserName.equals(existing.getText())) {
+                            return;
+                        }
+                    }
+                    MenuItem menuItem = new MenuItem(targetUserName);
+                    addWhisperChatButton.getItems().add(menuItem);
+                    menuItem.setOnAction(
+                            event ->
+                                    addWhisperChat(
+                                            targetUserName,
+                                            new ChatModel(
+                                                    ChatType.WHISPER,
+                                                    username,
+                                                    -1,
+                                                    targetUserName)));
+                });
+    }
+
+    public void removeWhisperUser(String targetUserName) {
+        Platform.runLater(
+                () ->
+                        addWhisperChatButton
+                                .getItems()
+                                .removeIf(item -> targetUserName.equals(item.getText())));
+    }
+
+    public void renameWhisperUser(String oldUsername, String newUsername) {
+        if (oldUsername == null
+                || newUsername == null
+                || oldUsername.isBlank()
+                || newUsername.isBlank()
+                || oldUsername.equals(newUsername)) {
+            return;
+        }
+
+        Platform.runLater(
+                () -> {
+                    for (MenuItem item : addWhisperChatButton.getItems()) {
+                        if (oldUsername.equals(item.getText())) {
+                            item.setText(newUsername);
+                            item.setOnAction(
+                                    event ->
+                                            addWhisperChat(
+                                                    newUsername,
+                                                    new ChatModel(
+                                                            ChatType.WHISPER,
+                                                            username,
+                                                            -1,
+                                                            newUsername)));
+                            break;
+                        }
+                    }
+
+                    Tab tab = usernameTabMap.remove(oldUsername);
+                    if (tab != null) {
+                        tab.setText(newUsername);
+                        usernameTabMap.put(newUsername, tab);
+                    }
+
+                    int idx = activeWhisperChats.indexOf(oldUsername);
+                    if (idx >= 0) {
+                        activeWhisperChats.set(idx, newUsername);
+                    }
+                });
+    }
+
+    /**
+     * Creates a new private (whisper) chat model for a specific target user, registers it within
+     * the chat system, and opens a new chat tab.
+     *
+     * @param target The username of the recipient for the private messages.
+     */
+    public void addWhisperChat(String target, ChatModel chatModel) {
+        if (!activeWhisperChats.contains(target)) {
+            activeWhisperChats.add(target);
+            ChatType whisper = ChatType.WHISPER;
+            chatController
+                    .getChatModelMap()
+                    .put(new ChatController.ChatKey(whisper, target), chatModel);
+            addChatTab(target, chatModel, whisper);
+        } else {
+            chatTabPane.getSelectionModel().select(usernameTabMap.get(target));
+        }
+    }
+
+    /**
+     * Dynamically loads a new chat tab from an FXML resource and attaches it to the TabPane. It
+     * initializes a {@link ChatViewController} for the tab and sets up a listener to display
+     * incoming messages in real-time.
+     *
+     * @param title The title to be displayed on the tab header.
+     * @param chatModel The {@link ChatModel} containing the data and logic for this specific chat.
+     * @throws RuntimeException If the FXML resource for the chat tab cannot be loaded.
+     */
+    public void addChatTab(String title, ChatModel chatModel, ChatType chatType) {
+        String ressource = "/ui-structure/components/chatui/chattab.fxml";
+        URL resource = getClass().getResource(ressource);
+        FXMLLoader fxmlLoader = new FXMLLoader(resource);
+        runOnPlatformSynchronized(
+                () -> {
+                    try {
+                        ChatViewController chatViewController =
+                                new ChatViewController(
+                                        this.chatController, chatModel, this.username);
+                        chatController.activeChatControllers.put(
+                                new ChatController.ChatKey(chatType), chatViewController);
+                        fxmlLoader.setController(chatViewController);
+                        Node load = fxmlLoader.load();
+                        VBox.setVgrow(load, Priority.ALWAYS);
+                        VBox vbox = new VBox();
+                        VBox.setVgrow(vbox, Priority.ALWAYS);
+                        vbox.getChildren().add(load);
+                        chatModel.addListener((msg) -> chatViewController.showMessage(msg));
+                        Tab newChat = new Tab(title, vbox);
+                        usernameTabMap.put(title, newChat);
+                        this.chatTabPane.getTabs().add(newChat);
+                        this.chatTabPane.getSelectionModel().select(newChat);
+                        return newChat;
+                    } catch (IOException e) {
+                        throw new RuntimeException(e);
+                    }
+                });
+    }
+
+    /**
+     * Helper Function to cope with a Threads problem occurring when the main JavaFX Thread performs
+     * the task to add a new whisper Chat tab, and the task is specified to runLater.
+     */
+    public static <T> T runOnPlatformSynchronized(Callable<T> code) {
+        if (Platform.isFxApplicationThread()) {
+            try {
+                return code.call();
+            } catch (Exception e) {
+                throw new RuntimeException(e);
+            }
+        } else {
+            CompletableFuture<T> futureLock = new CompletableFuture<>();
+            Platform.runLater(
+                    () -> {
+                        try {
+                            futureLock.complete(code.call());
+                        } catch (Exception e) {
+                            futureLock.completeExceptionally(e);
+                        }
+                    });
+            try {
+                return futureLock.get();
+            } catch (Throwable e) {
+                throw new RuntimeException(e);
+            }
+        }
+    }
+
+    public void loadChats() {
+        Map<ChatController.ChatKey, ChatModel> chatModelMap = chatController.getChatModelMap();
+        ChatController.ChatKey key = new ChatController.ChatKey(ChatType.GLOBAL);
+        ChatModel global = chatModelMap.get(key);
+        ChatViewController globalController = chatController.activeChatControllers.get(key);
+
+        for (String user : chatController.getLocalUserList()) {
+            addWhisperUser(user);
+        }
+
+        for (Message msg : global.messages) {
+            globalController.showMessage(msg);
+        }
+        for (String user : chatController.getLocalUserList()) {
+            ChatController.ChatKey whisperUserKey =
+                    new ChatController.ChatKey(ChatType.WHISPER, user);
+            if (chatModelMap.containsKey(whisperUserKey)) {
+                ChatModel whisperChatModel = chatModelMap.get(whisperUserKey);
+                addWhisperChat(user, whisperChatModel);
+                for (Message msg : whisperChatModel.messages) {
+                    chatController.activeChatControllers.get(whisperUserKey).showMessage(msg);
+                }
+            }
+        }
+    }
+}

src/main/java/ch/unibas/dmi/dbis/cs108/casono/client/ui/chatui/ChatController.java

@@ -1,90 +0,0 @@
-package ch.unibas.dmi.dbis.cs108.casono.client.ui.chatui;
-
-import java.time.LocalTime;
-import java.time.format.DateTimeFormatter;
-import javafx.fxml.FXML;
-import javafx.scene.control.Button;
-import javafx.scene.control.Label;
-import javafx.scene.control.ScrollPane;
-import javafx.scene.control.TextField;
-import javafx.scene.layout.VBox;
-
-/**
- * Controller-Klasse für das Chat-System innerhalb der Spieloberfläche.
- *
- * <p>Verwaltet das Anzeigen von Chatnachrichten, das Eingabefeld für eigene Nachrichten sowie den
- * Senden-Button. Unterstützt drei Arten von Nachrichten: - Player-to-Player (Privat) - Lobby-Chat
- * (Raum) - Globaler Chat (Serverweit)
- *
- * <p>Nachrichten werden in einem {@link VBox}-Container als {@link Label} angezeigt. Eigene
- * Nachrichten werden über {@link #onSendToNetwork(String)} an das Netzwerkprotokoll weitergeleitet,
- * während eingehende Nachrichten über {@link #receiveMessage(String, String)} verarbeitet und
- * angezeigt werden.
- *
- * <p>Hinweis: Einige TODOs stehen in der zugehörigen FXML-Datei
- */
-public class ChatController {
-
-    @FXML private VBox chatVBox;
-
-    @FXML private TextField inputField;
-
-    @FXML private Button sendButton;
-
-    @FXML private ScrollPane chatScrollPane;
-
-    private static final int CHAT_PADDING = 20;
-
-    /** Initialisiert den ChatController nach dem Laden der FXML. */
-    public void initialize() {
-        inputField.setOnAction(event -> sendMessage());
-        chatScrollPane.vvalueProperty().bind(chatVBox.heightProperty());
-    }
-
-    /** Standardkonstruktor. Wird von FXML verwendet. */
-    public ChatController() {
-        // default constructor for FXML
-    }
-
-    /**
-     * Diese Methode wird vom Senden-Button oder Enter ausgelöst. Sie gibt die eigene Nachricht an
-     * das Netzwerkprotokoll weiter.
-     */
-    @FXML
-    private void sendMessage() {
-        String message = inputField.getText().trim();
-        if (!message.isEmpty()) {
-            inputField.clear();
-
-            // Hier wird die eigene Nachricht ans Netzwerkprotokoll übergeben
-            onSendToNetwork(message);
-        }
-    }
-
-    /**
-     * Diese Funktion muss vom Netzwerkprotokoll aufgerufen werden, wenn eine neue Nachricht von
-     * einem anderen Spieler kommt.
-     *
-     * @param player Name des Spielers
-     * @param message Nachricht des Spielers
-     */
-    public void receiveMessage(String player, String message) {
-        String time = LocalTime.now().format(DateTimeFormatter.ofPattern("HH:mm"));
-        Label label = new Label("[" + time + "] " + player + ": " + message);
-        label.getStyleClass().add("info-text");
-        label.setWrapText(true); // Zeilenumbruch aktivieren
-        label.maxWidthProperty().bind(chatVBox.widthProperty().subtract(CHAT_PADDING));
-        chatVBox.getChildren().add(label);
-    }
-
-    /**
-     * Schnittstelle zum Netzwerkprotokoll. Diese Funktion wird automatisch aufgerufen, wenn der
-     * Benutzer eine eigene Nachricht sendet.
-     *
-     * @param message Nachricht, die der Benutzer abgeschickt hat
-     */
-    public void onSendToNetwork(String message) {
-        // TODO: Netzwerkcode einfügen
-        receiveMessage("Du", message);
-    }
-}

src/main/java/ch/unibas/dmi/dbis/cs108/casono/client/ui/chatui/ChatViewController.java

@@ -0,0 +1,103 @@
+package ch.unibas.dmi.dbis.cs108.casono.client.ui.chatui;
+
+import ch.unibas.dmi.dbis.cs108.casono.client.chat.ChatController;
+import ch.unibas.dmi.dbis.cs108.casono.client.chat.ChatModel;
+import ch.unibas.dmi.dbis.cs108.casono.client.chat.Message;
+import java.net.URL;
+import java.util.ResourceBundle;
+import javafx.application.Platform;
+import javafx.fxml.FXML;
+import javafx.fxml.Initializable;
+import javafx.scene.control.Button;
+import javafx.scene.control.Label;
+import javafx.scene.control.ScrollPane;
+import javafx.scene.control.TextField;
+import javafx.scene.layout.HBox;
+import javafx.scene.layout.VBox;
+
+/** Responsible for the presentation of the ChatModel to the Client */
+public class ChatViewController implements Initializable {
+
+    @FXML private Button sendButton;
+
+    @FXML private TextField inputField;
+
+    @FXML private VBox chatInterfaceVBox;
+
+    @FXML private HBox controlBar;
+
+    @FXML private ScrollPane scrollPane;
+
+    @FXML private VBox chat;
+
+    private final ChatModel chatModel;
+
+    private final String username;
+
+    private final ChatController controller;
+
+    private static final int CHAT_PADDING = 20;
+
+    public ChatViewController(ChatController chatController, ChatModel chatModel, String username) {
+        this.controller = chatController;
+        this.username = username;
+        this.chatModel = chatModel;
+    }
+
+    /**
+     * Initializes the controller after the FXML root element has been processed. Sets up event
+     * handlers for sending messages via the input field or button and ensures the ScrollPane
+     * automatically scrolls to the bottom when new messages are added.
+     *
+     * @param location The location used to resolve relative paths for the root object.
+     * @param resourceBundle The resources used to localize the root object.
+     */
+    @Override
+    public void initialize(URL location, ResourceBundle resourceBundle) {
+        inputField.setOnAction(event -> sendMessage());
+        sendButton.setOnAction(event -> sendMessage());
+        scrollPane.vvalueProperty().bind(chat.heightProperty());
+    }
+
+    /**
+     * Retrieves the text from the input field, creates a new {@link Message} object using the
+     * current model state, and passes it to the {@link ChatController} for network transmission.
+     * The input field is cleared after sending.
+     */
+    public void sendMessage() {
+        String message = inputField.getText().trim();
+        if (!message.isEmpty()) {
+            inputField.clear();
+            String currentUsername = controller.getCurrentUsername();
+            Message msg =
+                    new Message(
+                            chatModel.getChattype(),
+                            chatModel.lobbyId,
+                            currentUsername,
+                            chatModel.getTarget(),
+                            message);
+            controller.onSendToNetwork(msg);
+        }
+    }
+
+    /**
+     * Displays a message in the chat interface. This method creates a new Label for the message
+     * text and adds it to the message container. It uses {@link Platform#runLater(Runnable)} to
+     * ensure the UI update happens on the JavaFX Application Thread.
+     *
+     * @param msg The {@link Message} object containing the content and metadata to display.
+     */
+    public void showMessage(Message msg) {
+        Platform.runLater(
+                () -> {
+                    String msgText =
+                            String.format(
+                                    "[%s] %s: %s", msg.timestamp, msg.sender, msg.getMessage());
+                    Label label = new Label(msgText);
+                    label.getStyleClass().add("info-text");
+                    label.setWrapText(true);
+                    label.maxWidthProperty().bind(chat.widthProperty().subtract(CHAT_PADDING));
+                    chat.getChildren().add(label);
+                });
+    }
+}

src/main/java/ch/unibas/dmi/dbis/cs108/casono/client/ui/gameui/CasinoGameUI.java

@@ -1,8 +1,17 @@
 package ch.unibas.dmi.dbis.cs108.casono.client.ui.gameui;
 
+import ch.unibas.dmi.dbis.cs108.casono.client.ClientApp;
+import ch.unibas.dmi.dbis.cs108.casono.client.chat.ChatController;
+import ch.unibas.dmi.dbis.cs108.casono.client.game.GameService;
+import ch.unibas.dmi.dbis.cs108.casono.client.game.PlayerId;
+import ch.unibas.dmi.dbis.cs108.casono.client.network.ClientService;
+import ch.unibas.dmi.dbis.cs108.casono.client.network.GameClient;
 import java.io.IOException;
+import java.util.UUID;
+import java.util.logging.Logger;
 import javafx.application.Application;
 import javafx.fxml.FXMLLoader;
+import javafx.scene.Parent;
 import javafx.scene.Scene;
 import javafx.stage.Stage;
 
@@ -11,44 +20,152 @@ import javafx.stage.Stage;
  *
  * <p>Starts the JavaFX application, loads the graphical user interface from the FXML file, and
  * initializes the main stage for the game.
- *
- * <p>Tasks: - Loads the FXML interface "/ui-structure/Casinogameui.fxml". - Loads the application
- * icon from "/images/logoinverted.png". - Starts the application in full-screen mode.
  */
 public class CasinoGameUI extends Application {
 
-    /** default constructor */
+    private static final Logger LOG = Logger.getLogger(CasinoGameUI.class.getName());
+
+    private static ClientService clientService;
+    private static ChatController chatController;
+
+    private static String username;
+    private static int lobbyId = -1;
+
+    private static final int DEFAULT_WIDTH = 1200;
+    private static final int DEFAULT_HEIGHT = 800;
+    private static final int GUEST_ID_LENGTH = 8;
+
+    /** Default constructor for the CasinoGameUI application. */
     public CasinoGameUI() {
         // default no-arg constructor
     }
 
-    private static final int DEFAULT_WIDTH = 1200;
-    private static final int DEFAULT_HEIGHT = 800;
-
     /**
-     * Starts the main stage of the application.
+     * Sets the ClientService instance to be used by the application.
      *
-     * @param stage The main stage provided by the system.
-     * @throws IOException If the FXML file or resources cannot be loaded.
+     * @param clientService the ClientService instance to set
      */
-    @Override
-    public void start(Stage stage) throws IOException {
-        FXMLLoader fxmlLoader =
-                new FXMLLoader(CasinoGameUI.class.getResource("/ui-structure/Casinogameui.fxml"));
-        Scene scene = new Scene(fxmlLoader.load(), DEFAULT_WIDTH, DEFAULT_HEIGHT);
-        stage.setTitle("Casono (GAME)");
-
-        String iconPath = getClass().getResource("/images/logoinverted.png").toExternalForm();
-        stage.getIcons().add(new javafx.scene.image.Image(iconPath));
-        stage.setScene(scene);
-        stage.setFullScreen(true);
-        stage.show();
+    public static void setClientService(ClientService clientService) {
+        CasinoGameUI.clientService = clientService;
     }
 
     /**
-     * Starting point of the application.
+     * Sets the username to be used by the application.
      *
-     * @param args Command line arguments.
+     * @param username the username to set
+     */
+    public static void setUsername(String username) {
+        CasinoGameUI.username = username;
+    }
+
+    public static void setChatController(ChatController chatController) {
+        CasinoGameUI.chatController = chatController;
+    }
+
+    /**
+     * Sets the lobby ID to be used by the application.
+     *
+     * @param lobbyId the lobby ID to set
+     */
+    public static void setLobbyId(int lobbyId) {
+        CasinoGameUI.lobbyId = lobbyId;
+    }
+
+    /**
+     * The main entry point for the JavaFX application. This method is called after the application
+     * is
+     *
+     * @param stage the primary stage for this application, onto which the application scene can be
+     *     set. Applications may create other stages, if needed, but they will not be primary
+     *     stages.
+     * @throws IOException
+     */
+    @Override
+    public void start(Stage stage) throws IOException {
+
+        if (clientService == null) {
+            clientService = ClientApp.getSharedClientService();
+        }
+        if (clientService == null) {
+            throw new IllegalStateException(
+                    "CasinoGameUI: clientService is null. "
+                            + "Call CasinoGameUI.setClientService(...)"
+                            + " or start via ClientApp with a shared connection.");
+        }
+
+        String effectiveUsername = normalize(username);
+
+        if (effectiveUsername == null) {
+            effectiveUsername = normalize(ClientApp.getSharedUsername());
+        }
+
+        if (effectiveUsername == null) {
+            effectiveUsername =
+                    "Guest-" + UUID.randomUUID().toString().substring(0, GUEST_ID_LENGTH);
+        }
+
+        LOG.info(
+                "CasinoGameUI starting: effectiveUsername='"
+                        + effectiveUsername
+                        + "', injectedUsername='"
+                        + username
+                        + "', sharedUsername='"
+                        + ClientApp.getSharedUsername()
+                        + "', hasClientService="
+                        + (clientService != null));
+
+        FXMLLoader fxmlLoader =
+                new FXMLLoader(CasinoGameUI.class.getResource("/ui-structure/Casinogameui.fxml"));
+        Parent root = fxmlLoader.load();
+        CasinoGameController controller = fxmlLoader.getController();
+
+        if (lobbyId <= 0) {
+            throw new IllegalStateException("CasinoGameUI: lobbyId must be set before start()");
+        }
+
+        GameClient gameClient = new GameClient(clientService, lobbyId);
+        GameService gameService = new GameService(gameClient);
+        controller.setGameService(gameService);
+
+        controller.setMyPlayerId(PlayerId.of(effectiveUsername));
+        controller.setChatContext(effectiveUsername, clientService, lobbyId);
+
+        controller.startChat(chatController);
+
+        Scene scene = new Scene(root, DEFAULT_WIDTH, DEFAULT_HEIGHT);
+        stage.setTitle("Casono");
+
+        String iconPath = getClass().getResource("/images/logoinverted.png").toExternalForm();
+        stage.getIcons().add(new javafx.scene.image.Image(iconPath));
+
+        stage.setScene(scene);
+        stage.setFullScreen(true);
+        stage.setOnHidden(e -> controller.stop());
+        stage.show();
+
+        controller.start();
+    }
+
+    /**
+     * Normalizes a string by trimming whitespace and converting blank strings to null.
+     *
+     * @param s the string to normalize
+     * @return the normalized string, or null if the input is null or blank
+     */
+    private static String normalize(String s) {
+        if (s == null) {
+            return null;
+        }
+
+        String t = s.trim();
+        return t.isBlank() ? null : t;
+    }
+
+    /**
+     * The main method serves as the entry point for the application. It launches the JavaFX
+     * application.
+     *
+     * @param args command line arguments (not used)
      */
     public static void main(String[] args) {
         launch();

src/main/java/ch/unibas/dmi/dbis/cs108/casono/client/ui/gameui/gameuicomponents/CasinoBrowserController.java

@@ -4,17 +4,24 @@ import java.net.CookieHandler;
 import java.net.CookieManager;
 import java.net.CookiePolicy;
 import java.net.URI;
+import java.nio.file.Path;
+import java.nio.file.Paths;
 import java.util.HashSet;
+import java.util.Map;
 import java.util.Optional;
 import java.util.Set;
 import javafx.application.Platform;
+import javafx.collections.FXCollections;
+import javafx.collections.ObservableList;
 import javafx.geometry.Insets;
 import javafx.geometry.Pos;
 import javafx.scene.Scene;
 import javafx.scene.control.Alert;
 import javafx.scene.control.Button;
 import javafx.scene.control.ButtonType;
+import javafx.scene.control.ContextMenu;
 import javafx.scene.control.Label;
+import javafx.scene.control.MenuItem;
 import javafx.scene.control.TextField;
 import javafx.scene.image.Image;
 import javafx.scene.image.ImageView;
@@ -63,6 +70,11 @@ public class CasinoBrowserController {
 
     private static final Logger LOGGER = LogManager.getLogger(CasinoBrowserController.class);
 
+    private static final ObservableList<String> URL_SUGGESTIONS =
+            FXCollections.observableArrayList(TRUSTED_DOMAINS);
+
+    private static ContextMenu autoCompleteMenu = new ContextMenu();
+
     private static final int LOGO_HEIGHT = 40;
     private static final int CORNER_RADIUS = 40;
     private static final int HBOX_SPACIN = 10;
@@ -74,12 +86,15 @@ public class CasinoBrowserController {
     private static final int ALERT_HEIGHT = 300;
     private static final String LOGO_PATH = "/images/logoinverted.png";
     private static final String LOGO_PATH_MAIN = "/images/logo.png";
+    private static final int MAX_AUTOCOMPLETE_RESULTS = 5;
 
     static {
         CookieHandler.setDefault(COOKIE_MANAGER);
 
         TRUSTED_DOMAINS.add("wikipedia.org");
+        TRUSTED_DOMAINS.add("youtube.com");
         TRUSTED_DOMAINS.add("github.com");
+        TRUSTED_DOMAINS.add("search.brave.com");
         TRUSTED_DOMAINS.add("oracle.com");
         TRUSTED_DOMAINS.add("stackoverflow.com");
         TRUSTED_DOMAINS.add("docs.oracle.com");
@@ -94,10 +109,63 @@ public class CasinoBrowserController {
         TRUSTED_DOMAINS.add("metager.de");
         TRUSTED_DOMAINS.add("unibas.ch");
         TRUSTED_DOMAINS.add("mojeek.com");
-        TRUSTED_DOMAINS.add("searx.be ");
+        TRUSTED_DOMAINS.add("searx.be");
         TRUSTED_DOMAINS.add("startpage.com");
     }
 
+    /** Aliases for common websites. */
+    private static final java.util.Map<String, String> ALIASES =
+            Map.ofEntries(
+                    Map.entry("wiki", "wikipedia.org"),
+                    Map.entry("yt", "youtube.com"),
+                    Map.entry("bra", "search.brave.com"),
+                    Map.entry("bs", "search.brave.com"),
+                    Map.entry("gh", "github.com"),
+                    Map.entry("google", "google.com"),
+                    Map.entry("duck", "duckduckgo.com"),
+                    Map.entry("bing", "bing.com"),
+                    Map.entry("meta", "metager.de"),
+                    Map.entry("mojeek", "mojeek.com"),
+                    Map.entry("searx", "searx.be"),
+                    Map.entry("startpage", "startpage.com"),
+                    Map.entry("stack", "stackoverflow.com"),
+                    Map.entry("so", "stackoverflow.com"),
+                    Map.entry("oracle", "oracle.com"),
+                    Map.entry("docs", "docs.oracle.com"),
+                    Map.entry("mdn", "developer.mozilla.org"),
+                    Map.entry("maven", "maven.apache.org"),
+                    Map.entry("gradle", "gradle.org"),
+                    Map.entry("spring", "spring.io"),
+                    Map.entry("jetbrains", "jetbrains.com"),
+                    Map.entry("uni", "unibas.ch"));
+
+    /**
+     * Resolves user input into a valid URL.
+     *
+     * @param input User input from the URL field, which can be a full URL, a domain name, or an
+     *     alias.
+     * @return A properly formatted URL string that can be loaded by the browser, or the original
+     *     input if it cannot be resolved.
+     */
+    private static String resolveInputToUrl(String input) {
+        if (input == null || input.isBlank()) {
+            return input;
+        }
+
+        input = input.trim();
+
+        String alias = ALIASES.get(input.toLowerCase());
+        if (alias != null) {
+            return "https://" + alias;
+        }
+
+        if (input.matches("^[a-zA-Z][a-zA-Z0-9+.-]*://.*")) {
+            return input;
+        }
+
+        return "https://" + input;
+    }
+
     private static boolean javascriptEnabled = false;
 
     /** Deletes all cookies stored during the current browser session. */
@@ -124,6 +192,15 @@ public class CasinoBrowserController {
                     WebView webView = new WebView();
                     WebEngine engine = webView.getEngine();
 
+                    engine.locationProperty()
+                            .addListener(
+                                    (obs, oldUrl, newUrl) -> {
+                                        if (isDownloadUrl(newUrl)) {
+                                            LOGGER.warn("Download navigation blocked: " + newUrl);
+                                            engine.getLoadWorker().cancel();
+                                        }
+                                    });
+
                     engine.setJavaScriptEnabled(false);
 
                     configurePopupBlocker(engine);
@@ -203,9 +280,9 @@ public class CasinoBrowserController {
         engine.setCreatePopupHandler(
                 config -> {
                     Alert alert = new Alert(Alert.AlertType.WARNING);
-                    alert.setTitle("Popup blockiert");
+                    alert.setTitle("Popup blocked");
                     alert.setHeaderText(null);
-                    alert.setContentText("Popup wurde aus Sicherheitsgründen blockiert.");
+                    alert.setContentText("Casono Browser blocked a security threat.");
 
                     try {
                         var stream = CasinoBrowserController.class.getResourceAsStream(LOGO_PATH);
@@ -283,9 +360,90 @@ public class CasinoBrowserController {
         urlField.getStyleClass().add("gray-input-field");
         HBox.setHgrow(urlField, Priority.ALWAYS);
 
+        urlField.textProperty()
+                .addListener(
+                        (obs, oldText, newText) -> {
+                            if (newText == null || newText.isBlank()) {
+                                autoCompleteMenu.hide();
+                                return;
+                            }
+
+                            String input = newText.toLowerCase();
+
+                            String aliasMatch = ALIASES.get(input);
+                            if (aliasMatch != null) {
+                                autoCompleteMenu.getItems().clear();
+
+                                MenuItem item = new MenuItem(aliasMatch);
+                                item.setOnAction(
+                                        e -> {
+                                            urlField.setText("https://" + aliasMatch);
+                                            autoCompleteMenu.hide();
+                                        });
+
+                                autoCompleteMenu.getItems().add(item);
+                                autoCompleteMenu.show(urlField, javafx.geometry.Side.BOTTOM, 0, 0);
+                                return;
+                            }
+
+                            updateSuggestions(input, urlField);
+                        });
+
+        urlField.focusedProperty()
+                .addListener(
+                        (obs, oldVal, newVal) -> {
+                            if (!newVal) {
+                                autoCompleteMenu.hide();
+                            }
+                        });
+
         return urlField;
     }
 
+    /**
+     * Updates the autocomplete suggestions based on the current input in the URL field. Suggestions
+     * are filtered from the list of trusted domains and sorted to prioritize those that start with
+     * the input.
+     *
+     * @param input The current text input from the URL field, used to filter and sort suggestions.
+     * @param urlField The TextField for the URL input, used to position the autocomplete menu and
+     *     update its content.
+     */
+    private static void updateSuggestions(String input, TextField urlField) {
+        autoCompleteMenu.getItems().clear();
+
+        URL_SUGGESTIONS.stream()
+                .filter(
+                        domain ->
+                                domain.toLowerCase().startsWith(input)
+                                        || domain.toLowerCase().contains(input))
+                .sorted(
+                        (a, b) -> {
+                            boolean aStarts = a.startsWith(input);
+                            boolean bStarts = b.startsWith(input);
+                            return Boolean.compare(!aStarts, !bStarts);
+                        })
+                .limit(MAX_AUTOCOMPLETE_RESULTS)
+                .forEach(
+                        domain -> {
+                            MenuItem item = new MenuItem(domain);
+
+                            item.setOnAction(
+                                    e -> {
+                                        urlField.setText("https://" + domain);
+                                        autoCompleteMenu.hide();
+                                    });
+
+                            autoCompleteMenu.getItems().add(item);
+                        });
+
+        if (!autoCompleteMenu.getItems().isEmpty()) {
+            autoCompleteMenu.show(urlField, javafx.geometry.Side.BOTTOM, 0, 0);
+        } else {
+            autoCompleteMenu.hide();
+        }
+    }
+
     /**
      * Security Label
      *
@@ -305,7 +463,7 @@ public class CasinoBrowserController {
      * @return Toggle button
      */
     public static Button createJsToggle(WebEngine engine) {
-        Button jsToggle = new Button("JS EINSCHALTEN");
+        Button jsToggle = new Button("JS TURN ON");
         jsToggle.getStyleClass().add("red-button");
 
         jsToggle.setOnAction(
@@ -319,7 +477,7 @@ public class CasinoBrowserController {
                         jsToggle.getStyleClass().add("yellow-button");
 
                     } else {
-                        jsToggle.setText("JS EINSCHALTEN");
+                        jsToggle.setText("JS TURN ON");
                         jsToggle.getStyleClass().removeAll("yellow-button");
                         jsToggle.getStyleClass().add("red-button");
                     }
@@ -410,7 +568,16 @@ public class CasinoBrowserController {
      */
     public static void configureUrlEvents(
             WebEngine engine, TextField urlField, Label securityLabel) {
-        urlField.setOnAction(e -> loadUrlSafely(engine, urlField.getText(), securityLabel));
+        urlField.setOnKeyPressed(
+                e -> {
+                    if (e.getCode() == KeyCode.ENTER) {
+                        if (!autoCompleteMenu.isShowing()) {
+                            String resolved = resolveInputToUrl(urlField.getText());
+                            urlField.setText(resolved);
+                            loadUrlSafely(engine, resolved, securityLabel);
+                        }
+                    }
+                });
         engine.locationProperty().addListener((obs, o, n) -> urlField.setText(n));
     }
 
@@ -468,25 +635,54 @@ public class CasinoBrowserController {
      */
     private static void loadUrlSafely(WebEngine engine, String url, Label securityLabel) {
         try {
-            if (!url.startsWith("http")) {
+            if (!url.matches("^[a-zA-Z][a-zA-Z0-9+.-]*://.*")) {
                 url = "https://" + url;
             }
 
             URI uri = new URI(url);
+            String scheme = uri.getScheme();
 
-            // HTTPS required
-            if (!"https".equalsIgnoreCase(uri.getScheme())) {
+            String fullUrl = uri.toString();
+
+            if (isDownloadUrl(fullUrl)) {
+                securityLabel.setText("BLOCKED DOWNLOAD");
+
+                LOGGER.warn("Download blocked: " + fullUrl);
+                return;
+            }
+
+            if ("file".equalsIgnoreCase(scheme)) {
+                Path allowed =
+                        Paths.get(
+                                        System.getProperty("user.dir"),
+                                        "documents",
+                                        "docs",
+                                        "game-engine",
+                                        "manual.html")
+                                .normalize();
+
+                Path requested = Paths.get(uri).normalize();
+
+                if (requested.equals(allowed)) {
+                    securityLabel.setText("LOCAL OK");
+                    engine.load(uri.toString());
+                } else {
+                    securityLabel.setText("BLOCKED");
+                }
+                return;
+            }
+
+            if (!"https".equalsIgnoreCase(scheme)) {
                 securityLabel.setText("BLOCKED");
                 return;
             }
 
             String host = uri.getHost();
-            if (host == null) {
+            if (host == null || host.isBlank()) {
                 securityLabel.setText("ERROR");
                 return;
             }
 
-            // Secure Domain Check
             boolean trusted =
                     TRUSTED_DOMAINS.stream()
                             .anyMatch(domain -> host.equals(domain) || host.endsWith("." + domain));
@@ -500,9 +696,11 @@ public class CasinoBrowserController {
             } else {
                 securityLabel.setText("SAFE");
             }
+
             engine.load(uri.toString());
+
         } catch (Exception e) {
-            securityLabel.setText("ERROR");
+            securityLabel.setText("INVALID");
         }
     }
 
@@ -519,7 +717,7 @@ public class CasinoBrowserController {
         alert.setHeaderText("This website is unknown");
         String content =
                 host
-                        + "\n\nThis site has not been verified by the Casono browser.\n"
+                        + "\n\nThis site has not been verified by the Casono Browser.\n"
                         + "Do you still want to open it?";
         alert.setContentText(content);
 
@@ -545,4 +743,18 @@ public class CasinoBrowserController {
 
         return true;
     }
+
+    /**
+     * Checks if a given URL points to a downloadable file based on its extension.
+     *
+     * @param url the URL to check
+     * @return true if the URL is likely a download link, false otherwise
+     */
+    private static boolean isDownloadUrl(String url) {
+        if (url == null) {
+            return false;
+        }
+
+        return url.matches(".*\\.(exe|zip|dmg|msi|apk|jar|pdf)(\\?.*)?$");
+    }
 }

src/main/java/ch/unibas/dmi/dbis/cs108/casono/client/ui/gameui/gameuicomponents/HighscoreViewController.java

@@ -0,0 +1,114 @@
+package ch.unibas.dmi.dbis.cs108.casono.client.ui.gameui.gameuicomponents;
+
+import ch.unibas.dmi.dbis.cs108.casono.client.network.LobbyClient;
+import java.util.List;
+import javafx.fxml.FXML;
+import javafx.scene.Node;
+import javafx.scene.control.Label;
+import javafx.scene.control.ListView;
+import javafx.scene.input.MouseEvent;
+import javafx.stage.Stage;
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+
+/** Controller for the highscore popup window. */
+public class HighscoreViewController {
+
+    private static final Logger LOGGER = LogManager.getLogger(HighscoreViewController.class);
+
+    @FXML private ListView<String> highscoreList;
+    @FXML private Label statusLabel;
+    @FXML private Node highscoreRoot;
+
+    private LobbyClient lobbyClient;
+    private double dragOffsetX;
+    private double dragOffsetY;
+
+    public void setLobbyClient(LobbyClient lobbyClient) {
+        this.lobbyClient = lobbyClient;
+    }
+
+    /** Starts dragging the window from anywhere in the popup. */
+    @FXML
+    public void onPopupPressed(MouseEvent event) {
+        Stage stage = getStage();
+        if (stage == null) {
+            return;
+        }
+
+        dragOffsetX = stage.getX() - event.getScreenX();
+        dragOffsetY = stage.getY() - event.getScreenY();
+    }
+
+    /** Moves the popup window while the mouse is dragged anywhere on the popup. */
+    @FXML
+    public void onPopupDragged(MouseEvent event) {
+        Stage stage = getStage();
+        if (stage == null) {
+            return;
+        }
+
+        stage.setX(event.getScreenX() + dragOffsetX);
+        stage.setY(event.getScreenY() + dragOffsetY);
+    }
+
+    /** Returns the popup stage if the root is already attached to a scene. */
+    private Stage getStage() {
+        if (highscoreRoot == null || highscoreRoot.getScene() == null) {
+            return null;
+        }
+
+        return (Stage) highscoreRoot.getScene().getWindow();
+    }
+
+    /** Loads current highscores from the server and refreshes the list. */
+    @FXML
+    public void refreshHighscores() {
+        if (highscoreList == null || statusLabel == null) {
+            return;
+        }
+
+        if (lobbyClient == null) {
+            statusLabel.setText("Lobby client not initialized.");
+            return;
+        }
+
+        try {
+            List<String> entries = lobbyClient.getHighscores();
+            highscoreList.getItems().setAll(entries);
+            statusLabel.setText(
+                    entries.isEmpty() ? "No highscores yet." : entries.size() + " entries loaded.");
+        } catch (RuntimeException e) {
+            LOGGER.error("Failed to load highscores: {}", e.getMessage());
+            statusLabel.setText("Failed to load highscores.");
+        }
+    }
+
+    /** Clears all highscores globally on the server and reloads the list. */
+    @FXML
+    public void clearHighscores() {
+        if (lobbyClient == null || statusLabel == null) {
+            return;
+        }
+
+        try {
+            lobbyClient.clearHighscores();
+            refreshHighscores();
+            statusLabel.setText("Highscores cleared.");
+        } catch (RuntimeException e) {
+            LOGGER.error("Failed to clear highscores: {}", e.getMessage());
+            statusLabel.setText("Failed to clear highscores.");
+        }
+    }
+
+    /** Closes the highscore popup window. */
+    @FXML
+    public void closeWindow() {
+        if (highscoreList == null || highscoreList.getScene() == null) {
+            return;
+        }
+
+        Stage stage = (Stage) highscoreList.getScene().getWindow();
+        stage.close();
+    }
+}

src/main/java/ch/unibas/dmi/dbis/cs108/casono/client/ui/gameui/gameuicomponents/PlayerStatusController.java

@@ -0,0 +1,173 @@
+package ch.unibas.dmi.dbis.cs108.casono.client.ui.gameui.gameuicomponents;
+
+import ch.unibas.dmi.dbis.cs108.casono.client.game.Player;
+import ch.unibas.dmi.dbis.cs108.casono.client.game.PlayerState;
+import java.util.logging.Level;
+import java.util.logging.Logger;
+import javafx.fxml.FXML;
+import javafx.scene.control.Label;
+import javafx.scene.image.Image;
+import javafx.scene.image.ImageView;
+import javafx.scene.layout.HBox;
+import javafx.scene.layout.Pane;
+import javafx.scene.layout.VBox;
+
+/**
+ * Controller for displaying a player's status in the poker game, including their name, chip count
+ * and whether they are the dealer.
+ */
+public class PlayerStatusController {
+
+    private static final Logger LOGGER = Logger.getLogger(PlayerStatusController.class.getName());
+
+    @FXML private Label playerName;
+    @FXML private Label playerMoney;
+    @FXML private ImageView dealerIcon;
+    @FXML private Pane parent;
+    @FXML private VBox playerStatusBox;
+    @FXML private HBox statusInnerBoxTop;
+    @FXML private HBox statusInnerBoxBottom;
+
+    private Image dealerImage;
+    private Player player;
+    private boolean turnHighlighted;
+    private static final String DEALER_IMAGE_PATH = "/images/chip-dealer-blue-5.png";
+    private static final double DEALER_ICON_X_FACTOR = 0.8;
+    private static final String TURN_HIGHLIGHT_STYLE_CLASS = "player-status-active-turn";
+
+    /** Initialize the controller, load dealer image, and set up bindings. */
+    @FXML
+    public void initialize() {
+
+        try {
+            var url = getClass().getResource(DEALER_IMAGE_PATH);
+
+            if (url != null) {
+                dealerImage = new Image(url.toExternalForm(), true);
+                dealerIcon.setImage(dealerImage);
+            } else {
+                LOGGER.warning("Dealer image not found in resources!");
+            }
+
+        } catch (Exception e) {
+            LOGGER.log(Level.SEVERE, "Error loading dealer image", e);
+        }
+
+        dealerIcon.layoutXProperty().bind(parent.widthProperty().multiply(DEALER_ICON_X_FACTOR));
+        dealerIcon.setVisible(false);
+    }
+
+    /**
+     * Bind player to UI
+     *
+     * @param player The player whose status is to be displayed.
+     */
+    public void setPlayer(Player player) {
+        this.player = player;
+        if (player == null) {
+            turnHighlighted = false;
+        }
+        refresh();
+        updateTurnHighlightStyle();
+    }
+
+    /** Refresh UI safely */
+    public void refresh() {
+
+        if (player == null) {
+            playerName.setText("-");
+            playerMoney.setText("0 $");
+            dealerIcon.setVisible(false);
+            return;
+        }
+
+        // NAME (safe)
+        String name = player.getName();
+        playerName.setText(name != null ? name : "-");
+
+        // MONEY
+        playerMoney.setText(player.getChips() + " $");
+
+        // DEALER
+        boolean isDealer = player.getState() == PlayerState.DEALER;
+
+        dealerIcon.setVisible(isDealer);
+
+        if (isDealer && dealerImage != null) {
+            dealerIcon.setImage(dealerImage);
+        }
+    }
+
+    /**
+     * Highlight or unhighlight this player slot as the currently active turn.
+     *
+     * @param highlighted true if this slot should be highlighted, false otherwise.
+     */
+    public void setTurnHighlighted(boolean highlighted) {
+        this.turnHighlighted = highlighted;
+        updateTurnHighlightStyle();
+    }
+
+    /**
+     * Check whether the controller is currently bound to the provided player.
+     *
+     * @param candidate the player to compare against.
+     * @return true if both represent the same player.
+     */
+    public boolean hasPlayer(Player candidate) {
+        if (player == null
+                || candidate == null
+                || player.getId() == null
+                || candidate.getId() == null) {
+            return false;
+        }
+
+        return player.getId().equals(candidate.getId());
+    }
+
+    /**
+     * External quick update
+     *
+     * @param name The player's name to display.
+     * @param chips The player's chip count to display.
+     */
+    public void updatePlayer(String name, int chips) {
+        playerName.setText(name != null ? name : "-");
+        playerMoney.setText(chips + " $");
+    }
+
+    /**
+     * Force dealer state
+     *
+     * @param isDealer Whether the player is the dealer or not.
+     */
+    public void setDealer(boolean isDealer) {
+        dealerIcon.setVisible(isDealer);
+
+        if (isDealer && dealerImage != null) {
+            dealerIcon.setImage(dealerImage);
+        }
+    }
+
+    /**
+     * Update the visual style of the player status box to indicate whether it's currently this
+     * player's turn.
+     */
+    private void updateTurnHighlightStyle() {
+        if (statusInnerBoxTop == null || statusInnerBoxBottom == null) {
+            return;
+        }
+
+        if (turnHighlighted) {
+            if (!statusInnerBoxTop.getStyleClass().contains(TURN_HIGHLIGHT_STYLE_CLASS)) {
+                statusInnerBoxTop.getStyleClass().add(TURN_HIGHLIGHT_STYLE_CLASS);
+            }
+            if (!statusInnerBoxBottom.getStyleClass().contains(TURN_HIGHLIGHT_STYLE_CLASS)) {
+                statusInnerBoxBottom.getStyleClass().add(TURN_HIGHLIGHT_STYLE_CLASS);
+            }
+        } else {
+            statusInnerBoxTop.getStyleClass().remove(TURN_HIGHLIGHT_STYLE_CLASS);
+            statusInnerBoxBottom.getStyleClass().remove(TURN_HIGHLIGHT_STYLE_CLASS);
+        }
+    }
+}

src/main/java/ch/unibas/dmi/dbis/cs108/casono/client/ui/lobbyui/Casinomainui.java

@@ -19,8 +19,8 @@ public class Casinomainui extends Application {
         // Default constructor
     }
 
-    private static final int SCENE_WIDTH = 1200;
-    private static final int SCENE_HEIGHT = 800;
+    public static final int SCENE_WIDTH = 1200;
+    public static final int SCENE_HEIGHT = 800;
 
     @Override
     /**
@@ -30,6 +30,17 @@ public class Casinomainui extends Application {
      * @throws IOException If loading the FXML fails.
      */
     public void start(Stage stage) throws IOException {
+        // If the launcher passed an address argument (ip:port), expose it as
+        // system properties so controllers can read it without embedding defaults.
+        var raw = getParameters().getRaw();
+        if (raw != null && raw.size() > 0) {
+            String arg = raw.get(0);
+            String[] parts = arg.split(":", 2);
+            if (parts.length == 2) {
+                System.setProperty("casono.server.host", parts[0]);
+                System.setProperty("casono.server.port", parts[1]);
+            }
+        }
         FXMLLoader fxmlLoader =
                 new FXMLLoader(getClass().getResource("/ui-structure/Casinomainui.fxml"));
         Scene scene = new Scene(fxmlLoader.load(), SCENE_WIDTH, SCENE_HEIGHT);

src/main/java/ch/unibas/dmi/dbis/cs108/casono/client/ui/lobbyui/CasinomainuiController.java

@@ -1,14 +1,30 @@
 package ch.unibas.dmi.dbis.cs108.casono.client.ui.lobbyui;
 
+import ch.unibas.dmi.dbis.cs108.casono.client.ClientApp;
+import ch.unibas.dmi.dbis.cs108.casono.client.chat.ChatController;
+import ch.unibas.dmi.dbis.cs108.casono.client.network.ClientService;
+import ch.unibas.dmi.dbis.cs108.casono.client.network.LobbyClient;
+import ch.unibas.dmi.dbis.cs108.casono.client.ui.gameui.gameuicomponents.HighscoreViewController;
+import java.io.IOException;
+import java.net.URL;
 import javafx.application.Platform;
 import javafx.fxml.FXML;
+import javafx.fxml.FXMLLoader;
+import javafx.scene.Node;
+import javafx.scene.Parent;
+import javafx.scene.Scene;
+import javafx.scene.control.Alert;
+import javafx.scene.control.Alert.AlertType;
 import javafx.scene.control.Button;
 import javafx.scene.control.Label;
+import javafx.scene.control.TextField;
 import javafx.scene.image.Image;
 import javafx.scene.image.ImageView;
 import javafx.scene.layout.AnchorPane;
 import javafx.scene.layout.VBox;
 import javafx.scene.shape.Rectangle;
+import javafx.stage.Stage;
+import javafx.stage.StageStyle;
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 
@@ -23,17 +39,26 @@ public class CasinomainuiController {
     @FXML private Rectangle greenBox;
     @FXML private Button exitbutton;
     @FXML private VBox casinoTable;
+    @FXML private TextField usernameField;
+    @FXML private Button loginButton;
+    @FXML private AnchorPane chatContainer;
 
     private LobbyButtonTranslationManager translationManager;
     private LobbyButtonGridManager gridManager;
     private int nextButtonId = 1;
+    private LobbyClient lobbyClient;
+    private ChatController chatController;
 
-    /** Default constructor for dependency injection by FXMLLoader. */
+    /** Default constructor used by FXMLLoader. */
     public CasinomainuiController() {
         // Default constructor
     }
 
-    /** Initializes the UI components and sets default values. */
+    /**
+     * Initializes the UI components and sets default values. If a shared {@link ClientService}
+     * exists (created at application start), the controller reuses it so the connection remains
+     * open and already-logged-in.
+     */
     @FXML
     public void initialize() {
         titleLabel.setText("Casono");
@@ -41,8 +66,190 @@ public class CasinomainuiController {
         logoView.setImage(new Image(getClass().getResource("/images/logo.png").toExternalForm()));
 
         translationManager = LobbyButtonTranslationManager.getInstance();
+        String host = System.getProperty("casono.server.host");
+        int port = Integer.parseInt(System.getProperty("casono.server.port"));
+        ClientService clientService = ClientApp.getSharedClientService();
+        if (clientService == null) {
+            try {
+                clientService = new ClientService(host, port);
+            } catch (RuntimeException e) {
+                LOGGER.warn(
+                        "Could not connect to server {}:{} — starting in offline mode: {}",
+                        host,
+                        port,
+                        e.getMessage());
+                clientService = new ClientService(true); // offline mode
+            }
+        }
         gridManager =
-                new LobbyButtonGridManager(new javafx.scene.layout.GridPane(), translationManager);
+                new LobbyButtonGridManager(
+                        new javafx.scene.layout.GridPane(), translationManager, clientService);
+        // LobbyClient will use the provided ClientService; in offline mode calls will
+        // fail with RuntimeException
+        lobbyClient = new LobbyClient(clientService);
+        // Fetch existing lobbies from server on startup so newly-created lobbies
+        // by other clients are immediately visible.
+        try {
+            if (!lobbyClient.getClientService().isOffline()) {
+                var lobbies = lobbyClient.getLobbyList();
+                int bid = nextButtonId;
+                for (var li : lobbies) {
+                    try {
+                        translationManager.addLobbyButton(bid++, li.id);
+                    } catch (Exception e) {
+                        LOGGER.warn("Could not add lobby button: {}", e.getMessage());
+                    }
+                }
+                nextButtonId = bid;
+            }
+        } catch (RuntimeException e) {
+            LOGGER.warn("Failed to fetch lobby list at startup: {}", e.getMessage());
+        }
+        casinoTable.getChildren().clear();
+        casinoTable.getChildren().add(gridManager.getGridPane());
+        gridManager.renderLobbyButtons();
+
+        String sharedUsername = ClientApp.getSharedUsername();
+        updateUsernameFieldPresentation(sharedUsername);
+        if (loginButton != null) {
+            loginButton.setText(
+                    sharedUsername != null && !sharedUsername.isBlank() ? "Change Name" : "Login");
+        }
+
+        initializeChat(clientService);
+    }
+
+    /**
+     * Initializes the chat UI if a valid ClientService is available. If the client is offline or
+     * the
+     *
+     * @param clientService
+     */
+    private void initializeChat(ClientService clientService) {
+        if (clientService == null || clientService.isOffline() || chatContainer == null) {
+            return;
+        }
+        try {
+            String username = resolveChatUsername();
+            chatController = new ChatController(username, clientService);
+            URL resource = getClass().getResource("/ui-structure/components/chatui/chatbox.fxml");
+            FXMLLoader loader = new FXMLLoader(resource);
+            loader.setController(chatController.getChatBoxController());
+            Node chatNode = loader.load();
+            chatContainer.getChildren().setAll(chatNode);
+            AnchorPane.setTopAnchor(chatNode, 0.0);
+            AnchorPane.setBottomAnchor(chatNode, 0.0);
+            AnchorPane.setLeftAnchor(chatNode, 0.0);
+            AnchorPane.setRightAnchor(chatNode, 0.0);
+            gridManager.setChatController(chatController);
+        } catch (IOException e) {
+            LOGGER.warn("Could not initialize lobby chat UI: {}", e.getMessage());
+        }
+    }
+
+    /**
+     * Resolves the username to be used in the chat. It first checks for a shared username set at
+     * the
+     *
+     * @return The resolved username, or "Guest" if no valid username is found.
+     */
+    private String resolveChatUsername() {
+        String shared = ClientApp.getSharedUsername();
+        if (shared != null && !shared.isBlank()) {
+            return shared.trim();
+        }
+        if (usernameField != null
+                && usernameField.getText() != null
+                && !usernameField.getText().isBlank()) {
+            return usernameField.getText().trim();
+        }
+        return "Guest";
+    }
+
+    /** Handles the login button action. Validates input and calls LobbyClient.login(). */
+    @FXML
+    public void handleLoginButton() {
+        String username = usernameField == null ? null : usernameField.getText();
+        if (username == null || username.isBlank()) {
+            showAlert("Please enter a username.");
+            return;
+        }
+        // Only allow alphanumeric, _ and -
+        if (!username.matches("[a-zA-Z0-9_-]+")) {
+            showAlert("Only letters, numbers, '_' and '-' are allowed!");
+            return;
+        }
+        if (lobbyClient.getClientService().isOffline()) {
+            showAlert("Offline mode: cannot send login to server.");
+            return;
+        }
+
+        String trimmed = username.trim();
+        try {
+            var result = lobbyClient.login(trimmed);
+            String assigned = result != null ? result.getUsername() : trimmed;
+            ClientApp.updateSharedUsername(assigned);
+            if (chatController != null) {
+                chatController.updateUsername(assigned);
+            }
+            updateUsernameFieldPresentation(assigned);
+            if (loginButton != null) {
+                loginButton.setText("Change Name");
+            }
+            return;
+        } catch (RuntimeException loginError) {
+            if (!containsProtocolError(loginError, "ALREADY_LOGGED_IN")) {
+                LOGGER.error("Login failed: {}", loginError.getMessage());
+                showAlert("Login failed: " + loginError.getMessage());
+                return;
+            }
+            LOGGER.info("Session already logged in, trying username change");
+        }
+
+        try {
+            var result = lobbyClient.changeUsername(trimmed);
+            String assigned = result != null ? result.getUsername() : trimmed;
+            ClientApp.updateSharedUsername(assigned);
+            if (chatController != null) {
+                chatController.updateUsername(assigned);
+            }
+            updateUsernameFieldPresentation(assigned);
+            if (loginButton != null) {
+                loginButton.setText("Change Name");
+            }
+        } catch (RuntimeException e) {
+            LOGGER.error("Change username failed: {}", e.getMessage());
+            showAlert("Change username failed: " + e.getMessage());
+        }
+    }
+
+    private boolean containsProtocolError(RuntimeException error, String code) {
+        String msg = error.getMessage();
+        return msg != null && msg.contains(code);
+    }
+
+    private void updateUsernameFieldPresentation(String username) {
+        if (usernameField == null) {
+            return;
+        }
+
+        if (username != null && !username.isBlank()) {
+            usernameField.setText(username.trim());
+            usernameField.positionCaret(usernameField.getText().length());
+            usernameField.setPromptText("Username");
+        } else {
+            usernameField.clear();
+            usernameField.setPromptText("Username");
+        }
+    }
+
+    /** Shows an alert dialog with the given message. */
+    private void showAlert(String message) {
+        Alert alert = new Alert(AlertType.INFORMATION);
+        alert.setTitle("Info");
+        alert.setHeaderText(null);
+        alert.setContentText(message);
+        alert.showAndWait();
         casinoTable.getChildren().clear();
         casinoTable.getChildren().add(gridManager.getGridPane());
         gridManager.renderLobbyButtons();
@@ -51,10 +258,17 @@ public class CasinomainuiController {
     /** Handles the exit button action to close the application. */
     @FXML
     public void handleexitbutton() {
+        if (chatController != null) {
+            chatController.shutdown();
+        }
         Platform.exit();
     }
 
-    /** Handles creation of a new lobby button. */
+    /**
+     * Handles creation of a new lobby button. Attempts to create a lobby on the server via the
+     * {@link LobbyButtonGridManager} and registers the new button in the local translation manager.
+     * Errors are logged and displayed as an informational alert.
+     */
     @FXML
     public void handleCreateLobbyButton() {
         if (translationManager.isFull()) {
@@ -62,13 +276,53 @@ public class CasinomainuiController {
             return;
         }
         int buttonId = nextButtonId++;
-        int lobbyId = gridManager.createLobby();
         try {
+            String username = usernameField != null ? usernameField.getText() : "<unknown>";
+            LOGGER.info("Creating lobby for user: {}", username);
+            // avoid attempting to create a lobby when offline
+            if (lobbyClient.getClientService().isOffline()) {
+                LOGGER.warn("Cannot create lobby while offline");
+                showAlert("Offline mode: cannot create lobby.");
+                return;
+            }
+            int lobbyId = gridManager.createLobby();
             translationManager.addLobbyButton(buttonId, lobbyId);
             LOGGER.info("ButtonID: {}, LobbyID: {}", buttonId, lobbyId);
             gridManager.renderLobbyButtons();
         } catch (Exception e) {
-            LOGGER.error("Error while adding lobby button: {}", e.getMessage());
+            LOGGER.error("Failed to create or add lobby: {}", e.getMessage());
+        }
+    }
+
+    /** Opens the highscore popup from the lobby UI. */
+    @FXML
+    public void handleOpenHighscores() {
+        try {
+            FXMLLoader loader =
+                    new FXMLLoader(
+                            getClass()
+                                    .getResource(
+                                            "/ui-structure/gameuicomponents/HighscoreView.fxml"));
+            Parent root = loader.load();
+
+            HighscoreViewController controller = loader.getController();
+            controller.setLobbyClient(lobbyClient);
+            controller.refreshHighscores();
+
+            Stage stage = new Stage();
+            stage.initStyle(StageStyle.TRANSPARENT);
+            stage.setTitle("Casono Highscores");
+            String iconPath = getClass().getResource("/images/logoinverted.png").toExternalForm();
+            stage.getIcons().add(new Image(iconPath));
+            Scene scene = new Scene(root);
+            scene.setFill(javafx.scene.paint.Color.TRANSPARENT);
+            stage.setScene(scene);
+            stage.show();
+            stage.setAlwaysOnTop(true);
+            stage.toFront();
+        } catch (IOException e) {
+            LOGGER.warn("Could not open highscore window: {}", e.getMessage());
+            showAlert("Could not open highscore window.");
         }
     }
 }

src/main/java/ch/unibas/dmi/dbis/cs108/casono/client/ui/lobbyui/LobbyButtonGridManager.java

@@ -1,10 +1,22 @@
 package ch.unibas.dmi.dbis.cs108.casono.client.ui.lobbyui;
 
-/**
- * Manages the grid for lobby buttons and rendering. Uses LobbyButtonTranslationManager for mapping
- * ButtonID to LobbyID.
- */
+import ch.unibas.dmi.dbis.cs108.casono.client.ClientApp;
+import ch.unibas.dmi.dbis.cs108.casono.client.chat.ChatController;
+import ch.unibas.dmi.dbis.cs108.casono.client.network.ClientService;
+import ch.unibas.dmi.dbis.cs108.casono.client.network.LobbyClient;
+import ch.unibas.dmi.dbis.cs108.casono.client.ui.gameui.CasinoGameUI;
+import ch.unibas.dmi.dbis.cs108.casono.server.network.command.parsing.RequestParameter;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
 import java.util.Map;
+import java.util.concurrent.CompletableFuture;
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+import java.util.concurrent.ScheduledExecutorService;
+import java.util.concurrent.TimeUnit;
+import javafx.scene.Node;
 import javafx.scene.control.Button;
 import javafx.scene.image.Image;
 import javafx.scene.image.ImageView;
@@ -12,133 +24,574 @@ import javafx.scene.layout.GridPane;
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 
-/**
- * Manages the grid for lobby buttons and rendering. Uses LobbyButtonTranslationManager for mapping
- * ButtonID to LobbyID.
- */
 public class LobbyButtonGridManager {
-    private static final double BUTTON_WIDTH_MARGIN = 20.0;
+
+    private static final double BTN_WIDTH_MRG = 20.0;
     private static final double BUTTON_MIN_SIZE = 10.0;
+    private static final int REFRESH_INTERVAL_SECONDS = 5;
+    private static final int INITIAL_DELAY_SECONDS = 5;
+    private static final int COLS = 4;
+    private static final int MAX_BUTTONS = 8;
+    private static final int GUEST_ID_LENGTH = 8;
+
     private static final Logger LOGGER = LogManager.getLogger(LobbyButtonGridManager.class);
 
-    /** GridPane for the button grid. */
+    private static final String BUTTON_FALLBACK_IMAGE = "/images/lobbypictures/error.png";
+
+    private static final String BUTTON_IMAGE_TEMPLATE = "/images/lobbypictures/lobby_%d_%s.png";
+
     private final GridPane gridPane;
-
-    /** Manager for mapping ButtonID to LobbyID. */
     private final LobbyButtonTranslationManager translationManager;
+    private final LobbyClient lobbyClient;
 
-    /** Number of rows in the grid. */
-    private static final int ROWS = 2;
+    private ChatController chatController;
 
-    /** Number of columns in the grid. */
-    private static final int COLS = 4;
+    private final ConcurrentHashMap<String, Image> imageCache = new ConcurrentHashMap<>();
 
-    /** Path to the button image. */
-    private static final String BUTTON_IMAGE_PATH = "/images/logo.png";
+    private final ExecutorService executor = Executors.newCachedThreadPool();
 
-    /** Max random lobby id. */
-    private static final int MAX_RANDOM_LOBBY_ID = 10000;
+    private final ScheduledExecutorService scheduler = Executors.newSingleThreadScheduledExecutor();
 
-    /**
-     * Constructor for the GridManager.
-     *
-     * @param gridPane the GridPane for rendering
-     * @param translationManager the manager for mapping ButtonID to LobbyID
-     */
     public LobbyButtonGridManager(
-            GridPane gridPane, LobbyButtonTranslationManager translationManager) {
+            GridPane gridPane,
+            LobbyButtonTranslationManager translationManager,
+            LobbyClient lobbyClient) {
+
         this.gridPane = gridPane;
-        // Singleton immer verwenden
         this.translationManager = LobbyButtonTranslationManager.getInstance();
+        this.lobbyClient = lobbyClient;
+
+        startPeriodicRefresh(INITIAL_DELAY_SECONDS, REFRESH_INTERVAL_SECONDS);
     }
 
-    /**
-     * Renders all lobby buttons in the grid. Creates a button for each mapping with image and event
-     * handler.
-     */
-    public void renderLobbyButtons() {
-        gridPane.getChildren().clear();
-        int index = 0;
+    public LobbyButtonGridManager(
+            GridPane gridPane,
+            LobbyButtonTranslationManager translationManager,
+            ClientService clientService) {
+
+        this(gridPane, translationManager, new LobbyClient(clientService));
+
+        // Subscribe to server-initiated events so closed lobbies are removed
+        // immediately
+        clientService.addEventListener(this::handleClientServiceEvent);
+    }
+
+    private static record EventInfo(String event, String lobbyId) {}
+
+    private EventInfo extractEventInfo(List<RequestParameter> params) {
+        String evt = null;
+        String lidStr = null;
+        for (RequestParameter p : params) {
+            if ("EVENT".equalsIgnoreCase(p.key())) {
+                evt = p.value();
+            } else if ("LOBBY_ID".equalsIgnoreCase(p.key())) {
+                lidStr = p.value();
+            }
+        }
+        return new EventInfo(evt, lidStr);
+    }
+
+    private Integer tryParseInt(String s) {
+        try {
+            return Integer.parseInt(s);
+        } catch (NumberFormatException ex) {
+            return null;
+        }
+    }
+
+    private void handleLobbyClosed(int lid) {
+        LOGGER.info(
+                "LOBBY_CLOSED event for lobby {} — mapping before: {}",
+                lid,
+                translationManager.getButtonIdToLobbyId());
+        // find button id(s) for this lobby and remove mapping
         Map<Integer, Integer> mapping = translationManager.getButtonIdToLobbyId();
-        if (mapping.isEmpty()) {
-            // No buttons to render
+        Integer toRemove = null;
+        for (Map.Entry<Integer, Integer> e : mapping.entrySet()) {
+            if (e.getValue() != null && e.getValue().intValue() == lid) {
+                toRemove = e.getKey();
+                break;
+            }
+        }
+        if (toRemove != null) {
+            LOGGER.info(
+                    "Removing mapping for button {} -> lobby {} (LOBBY_CLOSED event)",
+                    toRemove,
+                    lid);
+            translationManager.removeLobbyButton(toRemove);
+            LOGGER.debug("Mapping after removal: {}", translationManager.getButtonIdToLobbyId());
+            javafx.application.Platform.runLater(this::renderLobbyButtons);
+        }
+    }
+
+    private void handleLobbyCreated(int lid) {
+        LOGGER.info(
+                "LOBBY_CREATED event for lobby {} — mapping before: {}",
+                lid,
+                translationManager.getButtonIdToLobbyId());
+
+        Map<Integer, Integer> mapping = translationManager.getButtonIdToLobbyId();
+
+        // If this lobby is already known, nothing to do
+        if (mapping.containsValue(lid)) {
+            LOGGER.debug("Lobby {} already mapped, skipping", lid);
             return;
         }
-        for (Map.Entry<Integer, Integer> entry : mapping.entrySet()) {
-            int buttonId = entry.getKey();
-            Button btn = new Button();
-            btn.setId("lobbyBtn-" + buttonId);
-            ImageView imageView =
-                    new ImageView(new Image(getClass().getResourceAsStream(BUTTON_IMAGE_PATH)));
-            imageView.setPreserveRatio(true);
-            // Dynamische Breite: Bindung an die Zellengröße
-            imageView
-                    .fitWidthProperty()
-                    .bind(gridPane.widthProperty().divide(COLS).subtract(BUTTON_WIDTH_MARGIN));
-            imageView.setSmooth(true);
-            btn.setGraphic(imageView);
-            btn.setMaxWidth(Double.MAX_VALUE);
-            btn.setMaxHeight(Double.MAX_VALUE);
-            btn.setMinWidth(BUTTON_MIN_SIZE);
-            btn.setMinHeight(BUTTON_MIN_SIZE);
-            GridPane.setHgrow(btn, javafx.scene.layout.Priority.ALWAYS);
-            GridPane.setVgrow(btn, javafx.scene.layout.Priority.ALWAYS);
-            btn.setOnAction(
-                    e -> {
-                        Integer lobbyId = translationManager.getLobbyIdForButton(buttonId);
-                        if (lobbyId != null) {
-                            joinLobby(lobbyId);
-                        }
-                    });
-            int row = index / COLS;
-            int col = index % COLS;
-            gridPane.add(btn, col, row);
-            index++;
+
+        // find next free button id (1..MAX_BUTTONS)
+        for (int candidate = 1; candidate <= MAX_BUTTONS; candidate++) {
+            if (!mapping.containsKey(candidate)) {
+                try {
+                    translationManager.addLobbyButton(candidate, lid);
+                    LOGGER.info("Mapped new lobby {} to button {}", lid, candidate);
+                    LOGGER.debug(
+                            "Mapping after add: {}", translationManager.getButtonIdToLobbyId());
+                    javafx.application.Platform.runLater(this::renderLobbyButtons);
+                    break;
+                } catch (Exception ex) {
+                    // grid full? try next candidate
+                    LOGGER.debug("Could not map created lobby {}: {}", lid, ex.getMessage());
+                }
+            }
         }
     }
 
-    /**
-     * Placeholder for lobby creation logic. Returns a generated lobbyId.
-     *
-     * @return The generated lobbyId
-     */
-    public int createLobby() {
-        // TODO: Replace with actual lobby creation logic
-        int lobbyId = (int) (Math.random() * MAX_RANDOM_LOBBY_ID + 1);
-        LOGGER.info("Lobby created: {}", lobbyId);
-        return lobbyId;
+    private void handleClientServiceEvent(List<String> lines) {
+        EventInfo info = extractEventInfo(ClientService.convertToRequestParameters(lines));
+
+        if (info.event() == null || info.lobbyId() == null) {
+            return;
+        }
+
+        Integer lid = tryParseInt(info.lobbyId());
+        if (lid == null) {
+            return;
+        }
+
+        if ("LOBBY_CLOSED".equalsIgnoreCase(info.event())) {
+            handleLobbyClosed(lid);
+        } else if ("LOBBY_CREATED".equalsIgnoreCase(info.event())) {
+            handleLobbyCreated(lid);
+        }
+    }
+
+    private void startPeriodicRefresh(long initialDelay, long period) {
+        scheduler.scheduleAtFixedRate(
+                this::refreshMappings, initialDelay, period, TimeUnit.SECONDS);
+    }
+
+    private void refreshMappings() {
+        Map<Integer, Integer> mapping = translationManager.getButtonIdToLobbyId();
+
+        // Always attempt to sync with server-side lobby list so clients that start
+        // after a lobby was created will discover it. This keeps the local mapping
+        // in sync with the server without requiring a restart.
+        List<LobbyClient.LobbyInfo> serverLobbies = null;
+        java.util.Set<Integer> serverIds = new java.util.HashSet<>();
+        try {
+            serverLobbies = lobbyClient.getLobbyList();
+            if (serverLobbies != null) {
+                for (var li : serverLobbies) {
+                    serverIds.add(li.id);
+                }
+            }
+            reconcileWithServerLobbies(serverLobbies);
+        } catch (Exception ex) {
+            LOGGER.debug("Could not fetch lobby list: {}", ex.getMessage());
+        }
+
+        if (mapping.isEmpty()) {
+            // mapping may still be empty after reconciliation
+            if (translationManager.getButtonIdToLobbyId().isEmpty()) {
+                return;
+            }
+            mapping = translationManager.getButtonIdToLobbyId();
+        }
+
+        List<Map.Entry<Integer, Integer>> entries = new ArrayList<>(mapping.entrySet());
+
+        for (Map.Entry<Integer, Integer> e : entries) {
+            int buttonId = e.getKey();
+            Integer lobbyIdObj = e.getValue();
+            if (lobbyIdObj == null) {
+                continue;
+            }
+            int lobbyId = lobbyIdObj.intValue();
+
+            CompletableFuture.supplyAsync(
+                            () -> {
+                                try {
+                                    return lobbyClient.fetchLobbyStatusString(lobbyId);
+                                } catch (Exception ex) {
+                                    LOGGER.info("Lobby {} missing: {}", lobbyId, ex.getMessage());
+                                    return null;
+                                }
+                            },
+                            executor)
+                    .thenAccept(
+                            status -> {
+                                // Do not remove a mapping just because the status fetch
+                                // temporarily returned null. Only remove mappings when
+                                // the server no longer lists the lobby (reconcileWithServerLobbies
+                                // handles removals based on authoritative server list).
+                                if (status == null) {
+                                    if (!serverIds.contains(lobbyId)) {
+                                        translationManager.removeLobbyButton(buttonId);
+                                        javafx.application.Platform.runLater(
+                                                this::renderLobbyButtons);
+                                    } else {
+                                        // treat as created/running later; keep mapping
+                                        LOGGER.debug(
+                                                "Missing status for lobby {} - keeping mapping",
+                                                lobbyId);
+                                    }
+                                }
+                            });
+        }
+    }
+
+    private void reconcileWithServerLobbies(List<LobbyClient.LobbyInfo> serverLobbies) {
+        if (serverLobbies == null) {
+            return;
+        }
+
+        Map<Integer, Integer> mapping = translationManager.getButtonIdToLobbyId();
+
+        // Build set of lobby ids returned by server
+        java.util.Set<Integer> serverIds = new java.util.HashSet<>();
+        for (var li : serverLobbies) {
+            serverIds.add(li.id);
+        }
+
+        LOGGER.debug("Reconciling mappings. serverIds={} mapping={}", serverIds, mapping);
+
+        // Remove mappings for lobbies that no longer exist
+        java.util.List<Integer> toRemove = new java.util.ArrayList<>();
+        for (var e : mapping.entrySet()) {
+            Integer lid = e.getValue();
+            if (lid == null) {
+                continue;
+            }
+            if (!serverIds.contains(lid)) {
+                toRemove.add(e.getKey());
+            }
+        }
+        for (Integer bid : toRemove) {
+            LOGGER.info(
+                    "Reconciling: removing mapping for button {} (server no longer lists lobby)",
+                    bid);
+            translationManager.removeLobbyButton(bid);
+        }
+
+        // Add server lobbies that are not yet mapped
+        for (var li : serverLobbies) {
+            if (mapping.containsValue(li.id)) {
+                continue;
+            }
+            // find next free button id (1..MAX_BUTTONS)
+            for (int candidate = 1; candidate <= MAX_BUTTONS; candidate++) {
+                if (!mapping.containsKey(candidate)) {
+                    try {
+                        translationManager.addLobbyButton(candidate, li.id);
+                        LOGGER.info(
+                                "Reconciling: added mapping button {} -> lobby {}",
+                                candidate,
+                                li.id);
+                        break;
+                    } catch (Exception ex) {
+                        // grid full? try next candidate
+                        LOGGER.debug(
+                                "Could not add mapping for lobby {}: {}", li.id, ex.getMessage());
+                    }
+                }
+            }
+        }
+
+        if (!toRemove.isEmpty() || !serverLobbies.isEmpty()) {
+            javafx.application.Platform.runLater(this::renderLobbyButtons);
+        }
+    }
+
+    public void renderLobbyButtons() {
+        gridPane.getChildren().clear();
+
+        Map<Integer, Integer> mapping = translationManager.getButtonIdToLobbyId();
+
+        if (mapping.isEmpty()) {
+            return;
+        }
+
+        List<Integer> buttonIds = new ArrayList<>(mapping.keySet());
+        Collections.sort(buttonIds);
+
+        for (int index = 0; index < buttonIds.size(); index++) {
+            Integer buttonId = buttonIds.get(index);
+            Integer lobbyIdObj = mapping.get(buttonId);
+            if (lobbyIdObj == null) {
+                continue;
+            }
+            int lobbyId = lobbyIdObj.intValue();
+
+            Button btn = createLobbyButton(buttonId, lobbyId);
+
+            int row = index / COLS;
+            int col = index % COLS;
+
+            gridPane.add(btn, col, row);
+        }
+    }
+
+    private Button createLobbyButton(int buttonId, int lobbyId) {
+        Button btn = new Button();
+        btn.setId("lobbyBtn-" + buttonId);
+
+        ImageView imageView = new ImageView(safeLoadImage(BUTTON_FALLBACK_IMAGE));
+
+        imageView.setPreserveRatio(true);
+        imageView
+                .fitWidthProperty()
+                .bind(gridPane.widthProperty().divide(COLS).subtract(BTN_WIDTH_MRG));
+
+        btn.setGraphic(imageView);
+        btn.setMaxWidth(Double.MAX_VALUE);
+        btn.setMaxHeight(Double.MAX_VALUE);
+        btn.setMinWidth(BUTTON_MIN_SIZE);
+        btn.setMinHeight(BUTTON_MIN_SIZE);
+
+        GridPane.setHgrow(btn, javafx.scene.layout.Priority.ALWAYS);
+        GridPane.setVgrow(btn, javafx.scene.layout.Priority.ALWAYS);
+
+        btn.setOnAction(
+                e -> {
+                    Integer targetLobbyId = translationManager.getLobbyIdForButton(buttonId);
+
+                    if (targetLobbyId != null) {
+                        joinLobby(targetLobbyId);
+                    }
+                });
+
+        loadLobbyImageAsync(btn, buttonId, lobbyId);
+
+        return btn;
+    }
+
+    private void loadLobbyImageAsync(Button btn, int buttonId, int lobbyId) {
+
+        CompletableFuture.supplyAsync(() -> lobbyClient.fetchLobbyStatusString(lobbyId), executor)
+                .thenAccept(
+                        statusStr -> {
+                            LobbyStatus status = parseLobbyStatus(statusStr);
+
+                            String path =
+                                    getImagePathForLobby(
+                                            lobbyId, status == null ? LobbyStatus.CREATED : status);
+
+                            Image img = safeLoadImage(path);
+
+                            javafx.application.Platform.runLater(
+                                    () -> {
+                                        ImageView iv = new ImageView(img);
+                                        iv.setPreserveRatio(true);
+                                        iv.fitWidthProperty()
+                                                .bind(
+                                                        gridPane.widthProperty()
+                                                                .divide(COLS)
+                                                                .subtract(BTN_WIDTH_MRG));
+                                        btn.setGraphic(iv);
+                                    });
+                        });
+    }
+
+    private enum LobbyStatus {
+        CREATED,
+        RUNNING
+    }
+
+    private LobbyStatus parseLobbyStatus(String statusStr) {
+        if (statusStr == null) {
+            return null;
+        }
+
+        try {
+            return LobbyStatus.valueOf(statusStr.trim().toUpperCase());
+        } catch (IllegalArgumentException e) {
+            return null;
+        }
+    }
+
+    private String getImagePathForLobby(int lobbyId, LobbyStatus status) {
+
+        String statusStr = status == LobbyStatus.CREATED ? "created" : "running";
+
+        return String.format(BUTTON_IMAGE_TEMPLATE, lobbyId, statusStr);
+    }
+
+    private Image safeLoadImage(String path) {
+        Image cached = imageCache.get(path);
+
+        if (cached != null) {
+            return cached;
+        }
+
+        java.io.InputStream is = getClass().getResourceAsStream(path);
+
+        if (is == null) {
+            is = getClass().getResourceAsStream(BUTTON_FALLBACK_IMAGE);
+        }
+
+        Image loaded = null;
+
+        try {
+            if (is != null) {
+                loaded = new Image(is);
+            }
+        } catch (Exception e) {
+            LOGGER.error("Image load failed: {}", path, e);
+        }
+
+        if (loaded != null) {
+            imageCache.put(path, loaded);
+        }
+
+        return loaded;
+    }
+
+    public void updateLobbyButtonImages() {
+        Map<Integer, Integer> mapping = translationManager.getButtonIdToLobbyId();
+
+        if (mapping.isEmpty()) {
+            return;
+        }
+
+        for (Integer buttonId : mapping.keySet()) {
+            Integer lobbyIdObj = mapping.get(buttonId);
+            if (lobbyIdObj == null) {
+                continue;
+            }
+            int lobbyId = lobbyIdObj.intValue();
+
+            CompletableFuture.supplyAsync(
+                            () -> {
+                                String statusStr = lobbyClient.fetchLobbyStatusString(lobbyId);
+
+                                LobbyStatus status = parseLobbyStatus(statusStr);
+
+                                return status == null ? LobbyStatus.CREATED : status;
+                            },
+                            executor)
+                    .thenAccept(
+                            status -> {
+                                String path = getImagePathForLobby(lobbyId, status);
+
+                                javafx.application.Platform.runLater(
+                                        () -> {
+                                            for (Node node : gridPane.getChildren()) {
+
+                                                boolean isButton = node instanceof Button;
+                                                boolean idMatches =
+                                                        ("lobbyBtn-" + buttonId)
+                                                                .equals(node.getId());
+
+                                                if (isButton && idMatches) {
+                                                    Button btn = (Button) node;
+
+                                                    ImageView iv =
+                                                            new ImageView(safeLoadImage(path));
+
+                                                    iv.setPreserveRatio(true);
+                                                    iv.fitWidthProperty()
+                                                            .bind(
+                                                                    gridPane.widthProperty()
+                                                                            .divide(COLS)
+                                                                            .subtract(
+                                                                                    BTN_WIDTH_MRG));
+
+                                                    btn.setGraphic(iv);
+                                                    break;
+                                                }
+                                            }
+                                        });
+                            });
+        }
+    }
+
+    public int createLobby() {
+        try {
+            int lobbyId = lobbyClient.createLobby();
+
+            if (lobbyId <= 0) {
+                throw new RuntimeException("Invalid lobby id: " + lobbyId);
+            }
+
+            return lobbyId;
+
+        } catch (Exception e) {
+            LOGGER.error("Create lobby failed: {}", e.getMessage());
+            throw new RuntimeException(e);
+        }
     }
 
-    /**
-     * Placeholder for joining a lobby.
-     *
-     * @param lobbyId The lobbyId to join
-     */
     public void joinLobby(int lobbyId) {
-        // Game-UI starten und Lobby-UI schließen
-        LOGGER.info("Joining lobby: {}", lobbyId);
+        try {
+            lobbyClient.joinLobby(lobbyId);
+        } catch (Exception e) {
+            LOGGER.error("Join failed: {}", e.getMessage());
+            return;
+        }
+
         javafx.application.Platform.runLater(
                 () -> {
-                    // Lobby-Stage schließen
                     javafx.stage.Stage currentStage =
                             (javafx.stage.Stage) gridPane.getScene().getWindow();
-                    currentStage.close();
-                    // Game-UI starten
+
+                    currentStage.hide();
+
+                    javafx.stage.Stage gameStage = new javafx.stage.Stage();
+
+                    gameStage.setOnHidden(
+                            ev -> {
+                                currentStage.show();
+                                refreshMappings();
+                                updateLobbyButtonImages();
+                            });
+
                     try {
-                        new ch.unibas.dmi.dbis.cs108.casono.client.ui.gameui.CasinoGameUI()
-                                .start(new javafx.stage.Stage());
+                        var cs = lobbyClient.getClientService();
+
+                        CasinoGameUI.setClientService(cs);
+                        CasinoGameUI.setLobbyId(lobbyId);
+                        CasinoGameUI.setChatController(chatController);
+
+                        String username = ClientApp.getSharedUsername();
+                        if (username == null || username.isBlank()) {
+                            username =
+                                    "Guest-"
+                                            + java.util
+                                                    .UUID
+                                                    .randomUUID()
+                                                    .toString()
+                                                    .substring(0, GUEST_ID_LENGTH);
+                        }
+                        CasinoGameUI.setUsername(username);
+
+                        new CasinoGameUI().start(gameStage);
+
                     } catch (Exception e) {
-                        LOGGER.error("Fehler beim Starten der Game-UI: {}", e.getMessage());
+                        LOGGER.error("Game UI failed: {}", e.getMessage());
+                        currentStage.show();
                     }
                 });
     }
 
-    /**
-     * Getter for the GridPane.
-     *
-     * @return The GridPane for the button grid
-     */
-    public javafx.scene.layout.GridPane getGridPane() {
+    public GridPane getGridPane() {
         return gridPane;
     }
+
+    public LobbyClient getLobbyClient() {
+        return lobbyClient;
+    }
+
+    public void setChatController(ChatController chatController) {
+        this.chatController = chatController;
+    }
 }

src/main/java/ch/unibas/dmi/dbis/cs108/casono/server/ServerApp.java

@@ -1,11 +1,56 @@
 package ch.unibas.dmi.dbis.cs108.casono.server;
 
+import ch.unibas.dmi.dbis.cs108.casono.server.app.commands.change_username.ChangeUsernameHandler;
+import ch.unibas.dmi.dbis.cs108.casono.server.app.commands.change_username.ChangeUsernameParser;
+import ch.unibas.dmi.dbis.cs108.casono.server.app.commands.change_username.ChangeUsernameRequest;
 import ch.unibas.dmi.dbis.cs108.casono.server.app.commands.check_nick.CheckUsernameHandler;
 import ch.unibas.dmi.dbis.cs108.casono.server.app.commands.check_nick.CheckUsernameParser;
 import ch.unibas.dmi.dbis.cs108.casono.server.app.commands.check_nick.CheckUsernameRequest;
+import ch.unibas.dmi.dbis.cs108.casono.server.app.commands.game.bet.PlayerBetHandler;
+import ch.unibas.dmi.dbis.cs108.casono.server.app.commands.game.bet.PlayerBetParser;
+import ch.unibas.dmi.dbis.cs108.casono.server.app.commands.game.bet.PlayerBetRequest;
+import ch.unibas.dmi.dbis.cs108.casono.server.app.commands.game.call.PlayerCallHandler;
+import ch.unibas.dmi.dbis.cs108.casono.server.app.commands.game.call.PlayerCallParser;
+import ch.unibas.dmi.dbis.cs108.casono.server.app.commands.game.call.PlayerCallRequest;
+import ch.unibas.dmi.dbis.cs108.casono.server.app.commands.game.fold.PlayerFoldHandler;
+import ch.unibas.dmi.dbis.cs108.casono.server.app.commands.game.fold.PlayerFoldParser;
+import ch.unibas.dmi.dbis.cs108.casono.server.app.commands.game.fold.PlayerFoldRequest;
+import ch.unibas.dmi.dbis.cs108.casono.server.app.commands.game.get_game_state.GetGameStateHandler;
+import ch.unibas.dmi.dbis.cs108.casono.server.app.commands.game.get_game_state.GetGameStateParser;
+import ch.unibas.dmi.dbis.cs108.casono.server.app.commands.game.get_game_state.GetGameStateRequest;
+import ch.unibas.dmi.dbis.cs108.casono.server.app.commands.game.raise.PlayerRaiseHandler;
+import ch.unibas.dmi.dbis.cs108.casono.server.app.commands.game.raise.PlayerRaiseParser;
+import ch.unibas.dmi.dbis.cs108.casono.server.app.commands.game.raise.PlayerRaiseRequest;
+import ch.unibas.dmi.dbis.cs108.casono.server.app.commands.get_message_count.GetMessageCountHandler;
+import ch.unibas.dmi.dbis.cs108.casono.server.app.commands.get_message_count.GetMessageCountParser;
+import ch.unibas.dmi.dbis.cs108.casono.server.app.commands.get_message_count.GetMessageCountRequest;
+import ch.unibas.dmi.dbis.cs108.casono.server.app.commands.get_next_message.GetNextMessageHandler;
+import ch.unibas.dmi.dbis.cs108.casono.server.app.commands.get_next_message.GetNextMessageParser;
+import ch.unibas.dmi.dbis.cs108.casono.server.app.commands.get_next_message.GetNextMessageRequest;
+import ch.unibas.dmi.dbis.cs108.casono.server.app.commands.highscore.clear_highscores.ClearHighscoresHandler;
+import ch.unibas.dmi.dbis.cs108.casono.server.app.commands.highscore.clear_highscores.ClearHighscoresParser;
+import ch.unibas.dmi.dbis.cs108.casono.server.app.commands.highscore.clear_highscores.ClearHighscoresRequest;
+import ch.unibas.dmi.dbis.cs108.casono.server.app.commands.highscore.get_highscores.GetHighscoresHandler;
+import ch.unibas.dmi.dbis.cs108.casono.server.app.commands.highscore.get_highscores.GetHighscoresParser;
+import ch.unibas.dmi.dbis.cs108.casono.server.app.commands.highscore.get_highscores.GetHighscoresRequest;
 import ch.unibas.dmi.dbis.cs108.casono.server.app.commands.list_users.ListUsersHandler;
 import ch.unibas.dmi.dbis.cs108.casono.server.app.commands.list_users.ListUsersParser;
 import ch.unibas.dmi.dbis.cs108.casono.server.app.commands.list_users.ListUsersRequest;
+import ch.unibas.dmi.dbis.cs108.casono.server.app.commands.lobby.create_lobby.CreateLobbyHandler;
+import ch.unibas.dmi.dbis.cs108.casono.server.app.commands.lobby.create_lobby.CreateLobbyParser;
+import ch.unibas.dmi.dbis.cs108.casono.server.app.commands.lobby.create_lobby.CreateLobbyRequest;
+import ch.unibas.dmi.dbis.cs108.casono.server.app.commands.lobby.get_lobby_list.GetLobbyListHandler;
+import ch.unibas.dmi.dbis.cs108.casono.server.app.commands.lobby.get_lobby_list.GetLobbyListParser;
+import ch.unibas.dmi.dbis.cs108.casono.server.app.commands.lobby.get_lobby_list.GetLobbyListRequest;
+import ch.unibas.dmi.dbis.cs108.casono.server.app.commands.lobby.get_lobby_status.GetLobbyStatusHandler;
+import ch.unibas.dmi.dbis.cs108.casono.server.app.commands.lobby.get_lobby_status.GetLobbyStatusParser;
+import ch.unibas.dmi.dbis.cs108.casono.server.app.commands.lobby.get_lobby_status.GetLobbyStatusRequest;
+import ch.unibas.dmi.dbis.cs108.casono.server.app.commands.lobby.join_lobby.JoinLobbyHandler;
+import ch.unibas.dmi.dbis.cs108.casono.server.app.commands.lobby.join_lobby.JoinLobbyParser;
+import ch.unibas.dmi.dbis.cs108.casono.server.app.commands.lobby.join_lobby.JoinLobbyRequest;
+import ch.unibas.dmi.dbis.cs108.casono.server.app.commands.lobby.start_game.StartGameHandler;
+import ch.unibas.dmi.dbis.cs108.casono.server.app.commands.lobby.start_game.StartGameParser;
+import ch.unibas.dmi.dbis.cs108.casono.server.app.commands.lobby.start_game.StartGameRequest;
 import ch.unibas.dmi.dbis.cs108.casono.server.app.commands.login.LoginHandler;
 import ch.unibas.dmi.dbis.cs108.casono.server.app.commands.login.LoginParser;
 import ch.unibas.dmi.dbis.cs108.casono.server.app.commands.login.LoginRequest;
@@ -15,9 +60,15 @@ import ch.unibas.dmi.dbis.cs108.casono.server.app.commands.logout.LogoutRequest;
 import ch.unibas.dmi.dbis.cs108.casono.server.app.commands.ping.PingHandler;
 import ch.unibas.dmi.dbis.cs108.casono.server.app.commands.ping.PingParser;
 import ch.unibas.dmi.dbis.cs108.casono.server.app.commands.ping.PingRequest;
+import ch.unibas.dmi.dbis.cs108.casono.server.app.commands.send_message.SendMessageHandler;
+import ch.unibas.dmi.dbis.cs108.casono.server.app.commands.send_message.SendMessageParser;
+import ch.unibas.dmi.dbis.cs108.casono.server.app.commands.send_message.SendMessageRequest;
+import ch.unibas.dmi.dbis.cs108.casono.server.domain.lobby.LobbyCleanupJob;
+import ch.unibas.dmi.dbis.cs108.casono.server.domain.lobby.LobbyManager;
 import ch.unibas.dmi.dbis.cs108.casono.server.domain.user.UserCleanupJob;
 import ch.unibas.dmi.dbis.cs108.casono.server.domain.user.UserRegistry;
 import ch.unibas.dmi.dbis.cs108.casono.server.network.NetworkManager;
+import ch.unibas.dmi.dbis.cs108.casono.server.network.command.execution.CommandHandler;
 import ch.unibas.dmi.dbis.cs108.casono.server.network.command.execution.CommandHandlerExecutor;
 import ch.unibas.dmi.dbis.cs108.casono.server.network.command.execution.CommandRouter;
 import ch.unibas.dmi.dbis.cs108.casono.server.network.command.parsing.CommandParserDispatcher;
@@ -40,7 +91,10 @@ public class ServerApp {
     private static final int USER_CLEANUP_JOB_RECONNECT_THRESHOLD = 10;
     private static final int SESSION_DISCONNECT_JOB_DELAY = 0;
     private static final int SESSION_DISCONNECT_JOB_PERIOD = 2;
-    private static final int SESSION_DISCONNECT_JOB_TIMEOUT = 5;
+    private static final int SESSION_DISCONNECT_JOB_TIMEOUT = 30;
+    private static final int LOBBY_EXPIRY_SECONDS = 30;
+    private static final int LOBBY_CLEANUP_INITIAL_DELAY_SECONDS = 5;
+    private static final int LOBBY_CLEANUP_PERIOD_SECONDS = 5;
 
     public static void start(String arg) {
         int port = Integer.parseInt(arg);
@@ -76,12 +130,31 @@ public class ServerApp {
                 SESSION_DISCONNECT_JOB_PERIOD,
                 TimeUnit.SECONDS);
 
-        registerCommands(dispatcher, router, responseDispatcher, userRegistry);
+        LobbyManager lobbyManager = new LobbyManager();
+        registerCommands(
+                dispatcher,
+                router,
+                responseDispatcher,
+                userRegistry,
+                new CommandContext(lobbyManager, sessionManager));
+
+        scheduler.scheduleAtFixedRate(
+                new LobbyCleanupJob(
+                        lobbyManager,
+                        sessionManager,
+                        responseDispatcher,
+                        Duration.ofSeconds(LOBBY_EXPIRY_SECONDS)),
+                LOBBY_CLEANUP_INITIAL_DELAY_SECONDS,
+                LOBBY_CLEANUP_PERIOD_SECONDS,
+                TimeUnit.SECONDS);
 
         NetworkManager networkManager = new NetworkManager(port, sessionManager, router);
         networkManager.start();
     }
 
+    private static record CommandContext(
+            LobbyManager lobbyManager, SessionManager sessionManager) {}
+
     /**
      * Registers command parsers and handlers.
      *
@@ -93,7 +166,8 @@ public class ServerApp {
             CommandParserDispatcher parserDispatcher,
             CommandRouter commandRouter,
             ResponseDispatcher responseDispatcher,
-            UserRegistry userRegistry) {
+            UserRegistry userRegistry,
+            CommandContext context) {
         parserDispatcher.register("PING", new PingParser());
         commandRouter.register(PingRequest.class, new PingHandler(responseDispatcher));
 
@@ -106,12 +180,129 @@ public class ServerApp {
         commandRouter.register(
                 LoginRequest.class, new LoginHandler(responseDispatcher, userRegistry));
 
+        parserDispatcher.register("CHANGE_USERNAME", new ChangeUsernameParser());
+        commandRouter.register(
+                ChangeUsernameRequest.class,
+                new ChangeUsernameHandler(
+                        responseDispatcher,
+                        userRegistry,
+                        context.lobbyManager(),
+                        context.sessionManager()));
+
         parserDispatcher.register("LOGOUT", new LogoutParser());
         commandRouter.register(
                 LogoutRequest.class, new LogoutHandler(responseDispatcher, userRegistry));
 
+        parserDispatcher.register("SEND_MESSAGE", new SendMessageParser());
+        commandRouter.register(
+                SendMessageRequest.class,
+                new SendMessageHandler(responseDispatcher, userRegistry, context.lobbyManager()));
+
+        parserDispatcher.register("GET_MESSAGE_COUNT", new GetMessageCountParser());
+        commandRouter.register(
+                GetMessageCountRequest.class,
+                new GetMessageCountHandler(responseDispatcher, userRegistry));
+
+        parserDispatcher.register("GET_NEXT_MESSAGE", new GetNextMessageParser());
+        commandRouter.register(
+                GetNextMessageRequest.class,
+                new GetNextMessageHandler(responseDispatcher, userRegistry));
+
         parserDispatcher.register("LIST_USERS", new ListUsersParser());
         commandRouter.register(
                 ListUsersRequest.class, new ListUsersHandler(responseDispatcher, userRegistry));
+
+        // GET_LOBBY_LIST registration
+        parserDispatcher.register("GET_LOBBY_LIST", new GetLobbyListParser());
+        commandRouter.register(
+                GetLobbyListRequest.class,
+                (CommandHandler<GetLobbyListRequest>)
+                        new GetLobbyListHandler(responseDispatcher, context.lobbyManager()));
+
+        // GET_GAME_STATE registration
+        parserDispatcher.register("GET_GAME_STATE", new GetGameStateParser());
+        commandRouter.register(
+                GetGameStateRequest.class,
+                (CommandHandler<GetGameStateRequest>)
+                        new GetGameStateHandler(
+                                responseDispatcher, context.lobbyManager(), userRegistry));
+
+        parserDispatcher.register("GET_HIGHSCORES", new GetHighscoresParser());
+        commandRouter.register(
+                GetHighscoresRequest.class,
+                (CommandHandler<GetHighscoresRequest>)
+                        new GetHighscoresHandler(responseDispatcher));
+
+        parserDispatcher.register("CLEAR_HIGHSCORES", new ClearHighscoresParser());
+        commandRouter.register(
+                ClearHighscoresRequest.class,
+                (CommandHandler<ClearHighscoresRequest>)
+                        new ClearHighscoresHandler(responseDispatcher));
+
+        // BET registration
+        parserDispatcher.register("BET", new PlayerBetParser());
+        commandRouter.register(
+                PlayerBetRequest.class,
+                (CommandHandler<PlayerBetRequest>)
+                        new PlayerBetHandler(
+                                responseDispatcher, userRegistry, context.lobbyManager()));
+
+        // RAISE registration
+        parserDispatcher.register("RAISE", new PlayerRaiseParser());
+        commandRouter.register(
+                PlayerRaiseRequest.class,
+                (CommandHandler<PlayerRaiseRequest>)
+                        new PlayerRaiseHandler(
+                                responseDispatcher, userRegistry, context.lobbyManager()));
+
+        // CALL registration
+        parserDispatcher.register("CALL", new PlayerCallParser());
+        commandRouter.register(
+                PlayerCallRequest.class,
+                (CommandHandler<PlayerCallRequest>)
+                        new PlayerCallHandler(
+                                responseDispatcher, userRegistry, context.lobbyManager()));
+
+        // FOLD registration
+        parserDispatcher.register("FOLD", new PlayerFoldParser());
+        commandRouter.register(
+                PlayerFoldRequest.class,
+                (CommandHandler<PlayerFoldRequest>)
+                        new PlayerFoldHandler(
+                                responseDispatcher, userRegistry, context.lobbyManager()));
+
+        // GET_LOBBY_STATUS registration
+        parserDispatcher.register("GET_LOBBY_STATUS", new GetLobbyStatusParser());
+        commandRouter.register(
+                GetLobbyStatusRequest.class,
+                (CommandHandler<GetLobbyStatusRequest>)
+                        new GetLobbyStatusHandler(
+                                responseDispatcher, context.lobbyManager(), userRegistry));
+
+        // CREATE_LOBBY registration
+        parserDispatcher.register("CREATE_LOBBY", new CreateLobbyParser());
+        commandRouter.register(
+                CreateLobbyRequest.class,
+                (CommandHandler<CreateLobbyRequest>)
+                        new CreateLobbyHandler(
+                                responseDispatcher,
+                                context.lobbyManager(),
+                                context.sessionManager()));
+
+        // JOIN_LOBBY registration
+        parserDispatcher.register("JOIN_LOBBY", new JoinLobbyParser());
+        commandRouter.register(
+                JoinLobbyRequest.class,
+                (CommandHandler<JoinLobbyRequest>)
+                        new JoinLobbyHandler(
+                                responseDispatcher, context.lobbyManager(), userRegistry));
+
+        // START_GAME registration
+        parserDispatcher.register("START_GAME", new StartGameParser());
+        commandRouter.register(
+                StartGameRequest.class,
+                (CommandHandler<StartGameRequest>)
+                        new StartGameHandler(
+                                responseDispatcher, context.lobbyManager(), userRegistry));
     }
 }

src/main/java/ch/unibas/dmi/dbis/cs108/casono/server/app/checks/GameLobbyExistsCheck.java

@@ -0,0 +1,75 @@
+package ch.unibas.dmi.dbis.cs108.casono.server.app.checks;
+
+import ch.unibas.dmi.dbis.cs108.casono.server.app.commands.game.bet.PlayerBetRequest;
+import ch.unibas.dmi.dbis.cs108.casono.server.app.commands.game.call.PlayerCallRequest;
+import ch.unibas.dmi.dbis.cs108.casono.server.app.commands.game.fold.PlayerFoldRequest;
+import ch.unibas.dmi.dbis.cs108.casono.server.app.commands.game.raise.PlayerRaiseRequest;
+import ch.unibas.dmi.dbis.cs108.casono.server.domain.lobby.Lobby;
+import ch.unibas.dmi.dbis.cs108.casono.server.domain.lobby.LobbyId;
+import ch.unibas.dmi.dbis.cs108.casono.server.domain.lobby.LobbyManager;
+import ch.unibas.dmi.dbis.cs108.casono.server.domain.user.User;
+import ch.unibas.dmi.dbis.cs108.casono.server.domain.user.UserRegistry;
+import ch.unibas.dmi.dbis.cs108.casono.server.network.command.execution.checks.HandlerCheck;
+import ch.unibas.dmi.dbis.cs108.casono.server.network.protocol.request.Request;
+import ch.unibas.dmi.dbis.cs108.casono.server.network.protocol.response.ErrorResponse;
+import ch.unibas.dmi.dbis.cs108.casono.server.network.protocol.response.Response;
+import java.util.Optional;
+
+/**
+ * Checks whether a target lobby exists for game action commands.
+ *
+ * <p>Supported commands are BET, CALL, FOLD and RAISE. If a request specifies a GAME_ID, the check
+ * validates that this lobby exists. Otherwise, it validates that the logged-in user is in a lobby.
+ */
+public class GameLobbyExistsCheck implements HandlerCheck {
+    private final UserRegistry userRegistry;
+    private final LobbyManager lobbyManager;
+
+    public GameLobbyExistsCheck(UserRegistry userRegistry, LobbyManager lobbyManager) {
+        this.userRegistry = userRegistry;
+        this.lobbyManager = lobbyManager;
+    }
+
+    @Override
+    public Optional<Response> check(Request request) {
+        Integer gameId = extractGameId(request);
+        User user = userRegistry.getBySessionId(request.getSessionId()).get();
+
+        Lobby lobby;
+        if (gameId != null) {
+            lobby = lobbyManager.getLobby(LobbyId.of(gameId));
+        } else {
+            lobby = lobbyManager.getLobbyByUsername(user.getName());
+        }
+
+        if (lobby != null) {
+            return Optional.empty();
+        }
+
+        if (gameId != null) {
+            return Optional.of(
+                    new ErrorResponse(request.getContext(), "LOBBY_NOT_FOUND", "Lobby not found"));
+        }
+
+        return Optional.of(
+                new ErrorResponse(request.getContext(), "NOT_IN_LOBBY", "User not in a lobby"));
+    }
+
+    private Integer extractGameId(Request request) {
+        if (request instanceof PlayerBetRequest) {
+            return ((PlayerBetRequest) request).getGameId();
+        }
+        if (request instanceof PlayerCallRequest) {
+            return ((PlayerCallRequest) request).getGameId();
+        }
+        if (request instanceof PlayerFoldRequest) {
+            return ((PlayerFoldRequest) request).getGameId();
+        }
+        if (request instanceof PlayerRaiseRequest) {
+            return ((PlayerRaiseRequest) request).getGameId();
+        }
+
+        throw new IllegalStateException(
+                "GameLobbyExistsCheck is only supported for BET, CALL, FOLD and RAISE requests");
+    }
+}

src/main/java/ch/unibas/dmi/dbis/cs108/casono/server/app/commands/add_player/AddPlayerHandler.java

@@ -0,0 +1,33 @@
+package ch.unibas.dmi.dbis.cs108.casono.server.app.commands.add_player;
+
+import ch.unibas.dmi.dbis.cs108.casono.server.domain.user.User;
+import ch.unibas.dmi.dbis.cs108.casono.server.domain.user.UserRegistry;
+import ch.unibas.dmi.dbis.cs108.casono.server.network.command.execution.CommandHandler;
+import ch.unibas.dmi.dbis.cs108.casono.server.network.protocol.response.ErrorResponse;
+import ch.unibas.dmi.dbis.cs108.casono.server.network.protocol.response.OkResponse;
+import ch.unibas.dmi.dbis.cs108.casono.server.network.protocol.response.dispatcher.ResponseDispatcher;
+import java.util.Optional;
+
+/** Handler for the ADD_PLAYER command. */
+public class AddPlayerHandler extends CommandHandler<AddPlayerRequest> {
+    private final UserRegistry userRegistry;
+
+    public AddPlayerHandler(UserRegistry userRegistry, ResponseDispatcher responseDispatcher) {
+        super(responseDispatcher);
+        this.userRegistry = userRegistry;
+    }
+
+    @Override
+    public void execute(AddPlayerRequest request) {
+        Optional<User> created =
+                userRegistry.registerIfAvailable(
+                        request.getName(), request.getContext().sessionId());
+        if (created.isEmpty()) {
+            responseDispatcher.dispatch(
+                    new ErrorResponse(request.getContext(), "NAME_TAKEN", "Name already taken"));
+            return;
+        }
+
+        responseDispatcher.dispatch(new OkResponse(request.getContext()));
+    }
+}

src/main/java/ch/unibas/dmi/dbis/cs108/casono/server/app/commands/add_player/AddPlayerParser.java

@@ -0,0 +1,20 @@
+package ch.unibas.dmi.dbis.cs108.casono.server.app.commands.add_player;
+
+import ch.unibas.dmi.dbis.cs108.casono.server.network.command.parsing.CommandParser;
+import ch.unibas.dmi.dbis.cs108.casono.server.network.protocol.request.PrimitiveRequest;
+import ch.unibas.dmi.dbis.cs108.casono.server.network.protocol.request.accessor.RequestParameterAccessor;
+
+/** Parser for the ADD_PLAYER command. */
+public class AddPlayerParser implements CommandParser<AddPlayerRequest> {
+    @Override
+    public AddPlayerRequest parse(PrimitiveRequest primitiveRequest) {
+        RequestParameterAccessor accessor =
+                new RequestParameterAccessor(primitiveRequest.parameters());
+
+        String name = accessor.require("NAME");
+
+        int chips = accessor.require("CHIPS", Integer::parseInt);
+
+        return new AddPlayerRequest(primitiveRequest.context(), name, chips);
+    }
+}

src/main/java/ch/unibas/dmi/dbis/cs108/casono/server/app/commands/add_player/AddPlayerRequest.java

@@ -0,0 +1,24 @@
+package ch.unibas.dmi.dbis.cs108.casono.server.app.commands.add_player;
+
+import ch.unibas.dmi.dbis.cs108.casono.server.network.protocol.request.Request;
+import ch.unibas.dmi.dbis.cs108.casono.server.network.protocol.request.RequestContext;
+
+/** Request data for the ADD_PLAYER command. */
+public class AddPlayerRequest extends Request {
+    private final String name;
+    private final int chips;
+
+    public AddPlayerRequest(RequestContext context, String name, int chips) {
+        super(context);
+        this.name = name;
+        this.chips = chips;
+    }
+
+    public String getName() {
+        return name;
+    }
+
+    public int getChips() {
+        return chips;
+    }
+}

src/main/java/ch/unibas/dmi/dbis/cs108/casono/server/app/commands/change_username/ChangeUsernameHandler.java

@@ -0,0 +1,112 @@
+package ch.unibas.dmi.dbis.cs108.casono.server.app.commands.change_username;
+
+import ch.unibas.dmi.dbis.cs108.casono.server.domain.lobby.LobbyManager;
+import ch.unibas.dmi.dbis.cs108.casono.server.domain.user.User;
+import ch.unibas.dmi.dbis.cs108.casono.server.domain.user.UserRegistry;
+import ch.unibas.dmi.dbis.cs108.casono.server.network.command.execution.CommandHandler;
+import ch.unibas.dmi.dbis.cs108.casono.server.network.protocol.request.RequestContext;
+import ch.unibas.dmi.dbis.cs108.casono.server.network.protocol.response.ErrorResponse;
+import ch.unibas.dmi.dbis.cs108.casono.server.network.protocol.response.SuccessResponse;
+import ch.unibas.dmi.dbis.cs108.casono.server.network.protocol.response.builder.ResponseBodyBuilder;
+import ch.unibas.dmi.dbis.cs108.casono.server.network.protocol.response.dispatcher.ResponseDispatcher;
+import ch.unibas.dmi.dbis.cs108.casono.server.network.sessions.Session;
+import ch.unibas.dmi.dbis.cs108.casono.server.network.sessions.SessionManager;
+import java.util.Optional;
+import java.util.regex.Pattern;
+
+/** Handles CHANGE_USERNAME requests for already logged-in users. */
+public class ChangeUsernameHandler extends CommandHandler<ChangeUsernameRequest> {
+    private static final Pattern VALID_USERNAME = Pattern.compile("[a-zA-Z0-9_-]+");
+    private final UserRegistry userRegistry;
+    private final LobbyManager lobbyManager;
+    private final SessionManager sessionManager;
+
+    /**
+     * @param responseDispatcher dispatcher used for responses
+     * @param userRegistry registry containing all users
+     * @param lobbyManager lobby manager used to keep lobby/game mappings in sync
+     * @param sessionManager session manager used to broadcast rename events
+     */
+    public ChangeUsernameHandler(
+            ResponseDispatcher responseDispatcher,
+            UserRegistry userRegistry,
+            LobbyManager lobbyManager,
+            SessionManager sessionManager) {
+        super(responseDispatcher);
+        this.userRegistry = userRegistry;
+        this.lobbyManager = lobbyManager;
+        this.sessionManager = sessionManager;
+    }
+
+    @Override
+    public void execute(ChangeUsernameRequest request) {
+        Optional<User> user = userRegistry.getBySessionId(request.getSessionId());
+        if (user.isEmpty()) {
+            responseDispatcher.dispatch(
+                    new ErrorResponse(
+                            request.getContext(),
+                            "USER_NOT_LOGGED_IN",
+                            "This session is not associated with an active user."));
+            return;
+        }
+
+        String newUsername = request.getUsername() == null ? "" : request.getUsername().trim();
+        if (newUsername.isEmpty() || !VALID_USERNAME.matcher(newUsername).matches()) {
+            responseDispatcher.dispatch(
+                    new ErrorResponse(
+                            request.getContext(),
+                            "INVALID_USERNAME",
+                            "Only letters, numbers, '_' and '-' are allowed."));
+            return;
+        }
+
+        User currentUser = user.get();
+        String oldUsername = currentUser.getName();
+        boolean changed = userRegistry.changeUsername(currentUser.getId(), newUsername);
+        if (!changed) {
+            responseDispatcher.dispatch(
+                    new ErrorResponse(
+                            request.getContext(),
+                            "USERNAME_TAKEN",
+                            "The requested username is already taken."));
+            return;
+        }
+
+        boolean lobbySynced =
+                lobbyManager == null || lobbyManager.renamePlayer(oldUsername, newUsername);
+        if (!lobbySynced) {
+            userRegistry.changeUsername(currentUser.getId(), oldUsername);
+            responseDispatcher.dispatch(
+                    new ErrorResponse(
+                            request.getContext(),
+                            "RENAME_CONFLICT",
+                            "Could not update username in current lobby/game state."));
+            return;
+        }
+
+        responseDispatcher.dispatch(
+                new ChangeUsernameResponse(
+                        request.getContext(), currentUser.getName(), currentUser.getId()));
+
+        broadcastUsernameChanged(oldUsername, currentUser.getName());
+    }
+
+    private void broadcastUsernameChanged(String oldUsername, String newUsername) {
+        if (sessionManager == null) {
+            return;
+        }
+
+        for (Session session : sessionManager.getAllSessions()) {
+            RequestContext ctx = new RequestContext(session.getId(), 0);
+            SuccessResponse ev =
+                    new SuccessResponse(
+                            ctx,
+                            new ResponseBodyBuilder()
+                                    .param("EVENT", "USERNAME_CHANGED")
+                                    .param("OLD_USERNAME", oldUsername)
+                                    .param("NEW_USERNAME", newUsername)
+                                    .build()) {};
+            responseDispatcher.dispatch(ev);
+        }
+    }
+}

src/main/java/ch/unibas/dmi/dbis/cs108/casono/server/app/commands/change_username/ChangeUsernameParser.java

@@ -0,0 +1,15 @@
+package ch.unibas.dmi.dbis.cs108.casono.server.app.commands.change_username;
+
+import ch.unibas.dmi.dbis.cs108.casono.server.network.command.parsing.CommandParser;
+import ch.unibas.dmi.dbis.cs108.casono.server.network.protocol.request.PrimitiveRequest;
+import ch.unibas.dmi.dbis.cs108.casono.server.network.protocol.request.accessor.RequestParameterAccessor;
+
+/** Parses CHANGE_USERNAME requests. */
+public class ChangeUsernameParser implements CommandParser<ChangeUsernameRequest> {
+    @Override
+    public ChangeUsernameRequest parse(PrimitiveRequest primitiveRequest) {
+        RequestParameterAccessor accessor =
+                new RequestParameterAccessor(primitiveRequest.parameters());
+        return new ChangeUsernameRequest(primitiveRequest.context(), accessor.require("USERNAME"));
+    }
+}

src/main/java/ch/unibas/dmi/dbis/cs108/casono/server/app/commands/change_username/ChangeUsernameRequest.java

@@ -0,0 +1,25 @@
+package ch.unibas.dmi.dbis.cs108.casono.server.app.commands.change_username;
+
+import ch.unibas.dmi.dbis.cs108.casono.server.network.protocol.request.Request;
+import ch.unibas.dmi.dbis.cs108.casono.server.network.protocol.request.RequestContext;
+
+/** Request used to change the username of the current session user. */
+public class ChangeUsernameRequest extends Request {
+    private final String username;
+
+    /**
+     * @param context request context for responses
+     * @param username desired new username
+     */
+    public ChangeUsernameRequest(RequestContext context, String username) {
+        super(context);
+        this.username = username;
+    }
+
+    /**
+     * @return desired new username
+     */
+    public String getUsername() {
+        return username;
+    }
+}

src/main/java/ch/unibas/dmi/dbis/cs108/casono/server/app/commands/change_username/ChangeUsernameResponse.java

@@ -0,0 +1,23 @@
+package ch.unibas.dmi.dbis.cs108.casono.server.app.commands.change_username;
+
+import ch.unibas.dmi.dbis.cs108.casono.server.domain.user.UserId;
+import ch.unibas.dmi.dbis.cs108.casono.server.network.protocol.request.RequestContext;
+import ch.unibas.dmi.dbis.cs108.casono.server.network.protocol.response.SuccessResponse;
+import ch.unibas.dmi.dbis.cs108.casono.server.network.protocol.response.builder.ResponseBodyBuilder;
+
+/** Response for successful username changes. */
+public class ChangeUsernameResponse extends SuccessResponse {
+    /**
+     * @param context request context
+     * @param username current username after the rename operation
+     * @param id user id of renamed user
+     */
+    public ChangeUsernameResponse(RequestContext context, String username, UserId id) {
+        super(
+                context,
+                new ResponseBodyBuilder()
+                        .param("USERNAME", username)
+                        .param("ID", id.value())
+                        .build());
+    }
+}

src/main/java/ch/unibas/dmi/dbis/cs108/casono/server/app/commands/game/bet/PlayerBetHandler.java

@@ -0,0 +1,102 @@
+package ch.unibas.dmi.dbis.cs108.casono.server.app.commands.game.bet;
+
+import ch.unibas.dmi.dbis.cs108.casono.server.app.checks.GameLobbyExistsCheck;
+import ch.unibas.dmi.dbis.cs108.casono.server.app.checks.UserLoggedInCheck;
+import ch.unibas.dmi.dbis.cs108.casono.server.domain.game.GameController;
+import ch.unibas.dmi.dbis.cs108.casono.server.domain.game.player.PlayerId;
+import ch.unibas.dmi.dbis.cs108.casono.server.domain.lobby.Lobby;
+import ch.unibas.dmi.dbis.cs108.casono.server.domain.lobby.LobbyId;
+import ch.unibas.dmi.dbis.cs108.casono.server.domain.lobby.LobbyManager;
+import ch.unibas.dmi.dbis.cs108.casono.server.domain.user.User;
+import ch.unibas.dmi.dbis.cs108.casono.server.domain.user.UserRegistry;
+import ch.unibas.dmi.dbis.cs108.casono.server.network.command.execution.CommandHandler;
+import ch.unibas.dmi.dbis.cs108.casono.server.network.protocol.response.ErrorResponse;
+import ch.unibas.dmi.dbis.cs108.casono.server.network.protocol.response.OkResponse;
+import ch.unibas.dmi.dbis.cs108.casono.server.network.protocol.response.dispatcher.ResponseDispatcher;
+import java.util.Optional;
+
+/**
+ * Handler for the `BET` command.
+ *
+ * <p>This handler validates the request (amount >= 0), resolves the user and target lobby (by
+ * `GAME_ID` when provided or by session username otherwise), checks that a game is running and then
+ * forwards the action to the {@code GameController}.
+ *
+ * <p>On failure the handler dispatches an {@link ErrorResponse} with an appropriate error code
+ * (e.g. {@code INVALID_AMOUNT}, {@code NOT_IN_LOBBY}, {@code LOBBY_NOT_FOUND}, {@code
+ * GAME_NOT_STARTED}, {@code GAME_ACTION_FAILED}). On success it dispatches an {@link OkResponse}.
+ */
+public class PlayerBetHandler extends CommandHandler<PlayerBetRequest> {
+    private final UserRegistry userRegistry;
+    private final LobbyManager lobbyManager;
+
+    /**
+     * Creates a new {@code PlayerBetHandler}.
+     *
+     * @param responseDispatcher dispatcher used to send responses back to the client
+     * @param userRegistry registry to resolve users from session ids
+     * @param lobbyManager manager used to lookup lobbies and their game controllers
+     */
+    public PlayerBetHandler(
+            ResponseDispatcher responseDispatcher,
+            UserRegistry userRegistry,
+            LobbyManager lobbyManager) {
+        super(responseDispatcher);
+        this.userRegistry = userRegistry;
+        this.lobbyManager = lobbyManager;
+        addCheck(new UserLoggedInCheck(userRegistry));
+        addCheck(new GameLobbyExistsCheck(userRegistry, lobbyManager));
+    }
+
+    /**
+     * Execute the bet request: validate parameters, resolve lobby and game, and forward the bet
+     * action to the game controller. Sends an {@link ErrorResponse} on failure or an {@link
+     * OkResponse} on success.
+     *
+     * @param request the parsed {@link PlayerBetRequest}
+     */
+    @Override
+    public void execute(PlayerBetRequest request) {
+        if (request.getAmount() < 0) {
+            responseDispatcher.dispatch(
+                    new ErrorResponse(
+                            request.getContext(), "INVALID_AMOUNT", "Amount must be non-negative"));
+            return;
+        }
+
+        Optional<User> opt = userRegistry.getBySessionId(request.getSessionId());
+        if (opt.isEmpty()) {
+            responseDispatcher.dispatch(
+                    new ErrorResponse(request.getContext(), "NOT_LOGGED_IN", "User not logged in"));
+            return;
+        }
+
+        String username = opt.get().getName();
+
+        Integer gameId = request.getGameId();
+        Lobby lobby;
+        if (gameId != null) {
+            lobby = lobbyManager.getLobby(LobbyId.of(gameId));
+        } else {
+            lobby = lobbyManager.getLobbyByUsername(username);
+        }
+
+        GameController game = lobby.getGameController();
+        if (game == null) {
+            responseDispatcher.dispatch(
+                    new ErrorResponse(
+                            request.getContext(), "GAME_NOT_STARTED", "Game not started"));
+            return;
+        }
+
+        try {
+            game.playerBet(PlayerId.of(username), request.getAmount());
+        } catch (Exception e) {
+            responseDispatcher.dispatch(
+                    new ErrorResponse(request.getContext(), "GAME_ACTION_FAILED", e.getMessage()));
+            return;
+        }
+
+        responseDispatcher.dispatch(new OkResponse(request.getContext()));
+    }
+}

src/main/java/ch/unibas/dmi/dbis/cs108/casono/server/app/commands/game/bet/PlayerBetParser.java

@@ -0,0 +1,40 @@
+package ch.unibas.dmi.dbis.cs108.casono.server.app.commands.game.bet;
+
+import ch.unibas.dmi.dbis.cs108.casono.server.network.command.parsing.CommandParser;
+import ch.unibas.dmi.dbis.cs108.casono.server.network.protocol.request.PrimitiveRequest;
+import ch.unibas.dmi.dbis.cs108.casono.server.network.protocol.request.accessor.RequestParameterAccessor;
+
+/**
+ * Parser for the `BET` command.
+ *
+ * <p>Parses the request parameters and builds a {@link PlayerBetRequest}. Expected parameters:
+ *
+ * <ul>
+ *   <li>`GAME_ID` (optional) - numeric id of the lobby/game to target
+ *   <li>`AMOUNT` (required) - amount to bet
+ * </ul>
+ */
+public class PlayerBetParser implements CommandParser<PlayerBetRequest> {
+    /**
+     * Parse a primitive request into a {@link PlayerBetRequest}.
+     *
+     * @param primitiveRequest the raw parsed request containing parameters and context
+     * @return a {@link PlayerBetRequest} with the parsed values (gameId may be null)
+     */
+    @Override
+    public PlayerBetRequest parse(PrimitiveRequest primitiveRequest) {
+        RequestParameterAccessor accessor =
+                new RequestParameterAccessor(primitiveRequest.parameters());
+
+        Integer gameId = null;
+        try {
+            gameId = accessor.optional("GAME_ID", null, Integer::parseInt);
+        } catch (Exception e) {
+            // parse handled by framework
+        }
+
+        int amount = accessor.require("AMOUNT", Integer::parseInt);
+
+        return new PlayerBetRequest(primitiveRequest.context(), gameId, amount);
+    }
+}

src/main/java/ch/unibas/dmi/dbis/cs108/casono/server/app/commands/game/bet/PlayerBetRequest.java

@@ -0,0 +1,45 @@
+package ch.unibas.dmi.dbis.cs108.casono.server.app.commands.game.bet;
+
+import ch.unibas.dmi.dbis.cs108.casono.server.network.protocol.request.Request;
+import ch.unibas.dmi.dbis.cs108.casono.server.network.protocol.request.RequestContext;
+
+/**
+ * Request for the `BET` command.
+ *
+ * <p>Contains the optional target `gameId` and the `amount` the player wants to bet.
+ */
+public class PlayerBetRequest extends Request {
+    private final Integer gameId;
+    private final int amount;
+
+    /**
+     * Creates a new {@code PlayerBetRequest}.
+     *
+     * @param context the request context
+     * @param gameId optional game id of the targeted lobby (may be {@code null})
+     * @param amount the bet amount (non-negative)
+     */
+    public PlayerBetRequest(RequestContext context, Integer gameId, int amount) {
+        super(context);
+        this.gameId = gameId;
+        this.amount = amount;
+    }
+
+    /**
+     * Returns the optional target game id.
+     *
+     * @return the game id or {@code null} if not provided
+     */
+    public Integer getGameId() {
+        return gameId;
+    }
+
+    /**
+     * Returns the requested bet amount.
+     *
+     * @return the bet amount
+     */
+    public int getAmount() {
+        return amount;
+    }
+}

src/main/java/ch/unibas/dmi/dbis/cs108/casono/server/app/commands/game/call/PlayerCallHandler.java

@@ -0,0 +1,90 @@
+package ch.unibas.dmi.dbis.cs108.casono.server.app.commands.game.call;
+
+import ch.unibas.dmi.dbis.cs108.casono.server.app.checks.GameLobbyExistsCheck;
+import ch.unibas.dmi.dbis.cs108.casono.server.app.checks.UserLoggedInCheck;
+import ch.unibas.dmi.dbis.cs108.casono.server.domain.game.GameController;
+import ch.unibas.dmi.dbis.cs108.casono.server.domain.game.player.PlayerId;
+import ch.unibas.dmi.dbis.cs108.casono.server.domain.lobby.Lobby;
+import ch.unibas.dmi.dbis.cs108.casono.server.domain.lobby.LobbyId;
+import ch.unibas.dmi.dbis.cs108.casono.server.domain.lobby.LobbyManager;
+import ch.unibas.dmi.dbis.cs108.casono.server.domain.user.User;
+import ch.unibas.dmi.dbis.cs108.casono.server.domain.user.UserRegistry;
+import ch.unibas.dmi.dbis.cs108.casono.server.network.command.execution.CommandHandler;
+import ch.unibas.dmi.dbis.cs108.casono.server.network.protocol.response.ErrorResponse;
+import ch.unibas.dmi.dbis.cs108.casono.server.network.protocol.response.OkResponse;
+import ch.unibas.dmi.dbis.cs108.casono.server.network.protocol.response.dispatcher.ResponseDispatcher;
+import java.util.Optional;
+
+/**
+ * Handler for the `CALL` command.
+ *
+ * <p>This handler validates the session, resolves the lobby (by `GAME_ID` when provided or by
+ * session username otherwise), checks for a running game and forwards the call action to the {@code
+ * GameController}.
+ */
+public class PlayerCallHandler extends CommandHandler<PlayerCallRequest> {
+    private final UserRegistry userRegistry;
+    private final LobbyManager lobbyManager;
+
+    /**
+     * Creates a new {@code PlayerCallHandler}.
+     *
+     * @param responseDispatcher dispatcher used to send responses back to the client
+     * @param userRegistry registry to resolve users from session ids
+     * @param lobbyManager manager used to lookup lobbies and their game controllers
+     */
+    public PlayerCallHandler(
+            ResponseDispatcher responseDispatcher,
+            UserRegistry userRegistry,
+            LobbyManager lobbyManager) {
+        super(responseDispatcher);
+        this.userRegistry = userRegistry;
+        this.lobbyManager = lobbyManager;
+        addCheck(new UserLoggedInCheck(userRegistry));
+        addCheck(new GameLobbyExistsCheck(userRegistry, lobbyManager));
+    }
+
+    /**
+     * Execute the call request: resolve lobby by `GAME_ID` if present, otherwise by session user,
+     * verify game is running, and forward the call to the game controller.
+     *
+     * @param request the parsed {@link PlayerCallRequest}
+     */
+    @Override
+    public void execute(PlayerCallRequest request) {
+        Optional<User> opt = userRegistry.getBySessionId(request.getSessionId());
+        if (opt.isEmpty()) {
+            responseDispatcher.dispatch(
+                    new ErrorResponse(request.getContext(), "NOT_LOGGED_IN", "User not logged in"));
+            return;
+        }
+
+        String username = opt.get().getName();
+
+        Integer gameId = request.getGameId();
+        Lobby lobby;
+        if (gameId != null) {
+            lobby = lobbyManager.getLobby(LobbyId.of(gameId));
+        } else {
+            lobby = lobbyManager.getLobbyByUsername(username);
+        }
+
+        GameController game = lobby.getGameController();
+        if (game == null) {
+            responseDispatcher.dispatch(
+                    new ErrorResponse(
+                            request.getContext(), "GAME_NOT_STARTED", "Game not started"));
+            return;
+        }
+
+        try {
+            game.playerCall(PlayerId.of(username));
+        } catch (RuntimeException e) {
+            responseDispatcher.dispatch(
+                    new ErrorResponse(request.getContext(), "GAME_ACTION_FAILED", e.getMessage()));
+            return;
+        }
+
+        responseDispatcher.dispatch(new OkResponse(request.getContext()));
+    }
+}

src/main/java/ch/unibas/dmi/dbis/cs108/casono/server/app/commands/game/call/PlayerCallParser.java

@@ -0,0 +1,28 @@
+package ch.unibas.dmi.dbis.cs108.casono.server.app.commands.game.call;
+
+import ch.unibas.dmi.dbis.cs108.casono.server.network.command.parsing.CommandParser;
+import ch.unibas.dmi.dbis.cs108.casono.server.network.protocol.request.PrimitiveRequest;
+import ch.unibas.dmi.dbis.cs108.casono.server.network.protocol.request.accessor.RequestParameterAccessor;
+
+/**
+ * Parser for the `CALL` command.
+ *
+ * <p>Accepts an optional `GAME_ID` parameter. If provided, the handler will target the specified
+ * lobby; otherwise the server resolves the lobby by the requesting session's user.
+ */
+public class PlayerCallParser implements CommandParser<PlayerCallRequest> {
+    @Override
+    public PlayerCallRequest parse(PrimitiveRequest primitiveRequest) {
+        RequestParameterAccessor accessor =
+                new RequestParameterAccessor(primitiveRequest.parameters());
+
+        Integer gameId = null;
+        try {
+            gameId = accessor.optional("GAME_ID", null, Integer::parseInt);
+        } catch (Exception e) {
+            // parse errors handled by framework
+        }
+
+        return new PlayerCallRequest(primitiveRequest.context(), gameId);
+    }
+}

src/main/java/ch/unibas/dmi/dbis/cs108/casono/server/app/commands/game/call/PlayerCallRequest.java

@@ -0,0 +1,34 @@
+package ch.unibas.dmi.dbis.cs108.casono.server.app.commands.game.call;
+
+import ch.unibas.dmi.dbis.cs108.casono.server.network.protocol.request.Request;
+import ch.unibas.dmi.dbis.cs108.casono.server.network.protocol.request.RequestContext;
+
+/**
+ * Request for the `CALL` command.
+ *
+ * <p>Contains an optional `gameId` when the client targets a specific lobby, otherwise the server
+ * will resolve the lobby from the requesting session's user.
+ */
+public class PlayerCallRequest extends Request {
+    private final Integer gameId;
+
+    /**
+     * Creates a new {@code PlayerCallRequest}.
+     *
+     * @param context the request context
+     * @param gameId optional game id of the targeted lobby (may be {@code null})
+     */
+    public PlayerCallRequest(RequestContext context, Integer gameId) {
+        super(context);
+        this.gameId = gameId;
+    }
+
+    /**
+     * Returns the optional target game id.
+     *
+     * @return the game id or {@code null} if not provided
+     */
+    public Integer getGameId() {
+        return gameId;
+    }
+}

src/main/java/ch/unibas/dmi/dbis/cs108/casono/server/app/commands/game/fold/PlayerFoldHandler.java

@@ -0,0 +1,90 @@
+package ch.unibas.dmi.dbis.cs108.casono.server.app.commands.game.fold;
+
+import ch.unibas.dmi.dbis.cs108.casono.server.app.checks.GameLobbyExistsCheck;
+import ch.unibas.dmi.dbis.cs108.casono.server.app.checks.UserLoggedInCheck;
+import ch.unibas.dmi.dbis.cs108.casono.server.domain.game.GameController;
+import ch.unibas.dmi.dbis.cs108.casono.server.domain.game.player.PlayerId;
+import ch.unibas.dmi.dbis.cs108.casono.server.domain.lobby.Lobby;
+import ch.unibas.dmi.dbis.cs108.casono.server.domain.lobby.LobbyId;
+import ch.unibas.dmi.dbis.cs108.casono.server.domain.lobby.LobbyManager;
+import ch.unibas.dmi.dbis.cs108.casono.server.domain.user.User;
+import ch.unibas.dmi.dbis.cs108.casono.server.domain.user.UserRegistry;
+import ch.unibas.dmi.dbis.cs108.casono.server.network.command.execution.CommandHandler;
+import ch.unibas.dmi.dbis.cs108.casono.server.network.protocol.response.ErrorResponse;
+import ch.unibas.dmi.dbis.cs108.casono.server.network.protocol.response.OkResponse;
+import ch.unibas.dmi.dbis.cs108.casono.server.network.protocol.response.dispatcher.ResponseDispatcher;
+import java.util.Optional;
+
+/**
+ * Handler for the `FOLD` command.
+ *
+ * <p>This handler validates the session, resolves the lobby (by `GAME_ID` when provided or by
+ * session username otherwise), checks for a running game and forwards the fold action to the {@code
+ * GameController}.
+ */
+public class PlayerFoldHandler extends CommandHandler<PlayerFoldRequest> {
+    private final UserRegistry userRegistry;
+    private final LobbyManager lobbyManager;
+
+    /**
+     * Creates a new {@code PlayerFoldHandler}.
+     *
+     * @param responseDispatcher dispatcher used to send responses back to the client
+     * @param userRegistry registry to resolve users from session ids
+     * @param lobbyManager manager used to lookup lobbies and their game controllers
+     */
+    public PlayerFoldHandler(
+            ResponseDispatcher responseDispatcher,
+            UserRegistry userRegistry,
+            LobbyManager lobbyManager) {
+        super(responseDispatcher);
+        this.userRegistry = userRegistry;
+        this.lobbyManager = lobbyManager;
+        addCheck(new UserLoggedInCheck(userRegistry));
+        addCheck(new GameLobbyExistsCheck(userRegistry, lobbyManager));
+    }
+
+    /**
+     * Execute the fold request: resolve lobby by `GAME_ID` if present, otherwise by session user,
+     * verify game is running, and forward the fold to the game controller.
+     *
+     * @param request the parsed {@link PlayerFoldRequest}
+     */
+    @Override
+    public void execute(PlayerFoldRequest request) {
+        Optional<User> opt = userRegistry.getBySessionId(request.getSessionId());
+        if (opt.isEmpty()) {
+            responseDispatcher.dispatch(
+                    new ErrorResponse(request.getContext(), "NOT_LOGGED_IN", "User not logged in"));
+            return;
+        }
+
+        String username = opt.get().getName();
+
+        Integer gameId = request.getGameId();
+        Lobby lobby;
+        if (gameId != null) {
+            lobby = lobbyManager.getLobby(LobbyId.of(gameId));
+        } else {
+            lobby = lobbyManager.getLobbyByUsername(username);
+        }
+
+        GameController game = lobby.getGameController();
+        if (game == null) {
+            responseDispatcher.dispatch(
+                    new ErrorResponse(
+                            request.getContext(), "GAME_NOT_STARTED", "Game not started"));
+            return;
+        }
+
+        try {
+            game.playerFold(PlayerId.of(username));
+        } catch (RuntimeException e) {
+            responseDispatcher.dispatch(
+                    new ErrorResponse(request.getContext(), "GAME_ACTION_FAILED", e.getMessage()));
+            return;
+        }
+
+        responseDispatcher.dispatch(new OkResponse(request.getContext()));
+    }
+}

src/main/java/ch/unibas/dmi/dbis/cs108/casono/server/app/commands/game/fold/PlayerFoldParser.java

@@ -0,0 +1,28 @@
+package ch.unibas.dmi.dbis.cs108.casono.server.app.commands.game.fold;
+
+import ch.unibas.dmi.dbis.cs108.casono.server.network.command.parsing.CommandParser;
+import ch.unibas.dmi.dbis.cs108.casono.server.network.protocol.request.PrimitiveRequest;
+import ch.unibas.dmi.dbis.cs108.casono.server.network.protocol.request.accessor.RequestParameterAccessor;
+
+/**
+ * Parser for the `FOLD` command.
+ *
+ * <p>Accepts an optional `GAME_ID` parameter. If provided, the handler will target the specified
+ * lobby; otherwise the server resolves the lobby by the requesting session's user.
+ */
+public class PlayerFoldParser implements CommandParser<PlayerFoldRequest> {
+    @Override
+    public PlayerFoldRequest parse(PrimitiveRequest primitiveRequest) {
+        RequestParameterAccessor accessor =
+                new RequestParameterAccessor(primitiveRequest.parameters());
+
+        Integer gameId = null;
+        try {
+            gameId = accessor.optional("GAME_ID", null, Integer::parseInt);
+        } catch (Exception e) {
+            // parse handled by framework
+        }
+
+        return new PlayerFoldRequest(primitiveRequest.context(), gameId);
+    }
+}

src/main/java/ch/unibas/dmi/dbis/cs108/casono/server/app/commands/game/fold/PlayerFoldRequest.java

@@ -0,0 +1,34 @@
+package ch.unibas.dmi.dbis.cs108.casono.server.app.commands.game.fold;
+
+import ch.unibas.dmi.dbis.cs108.casono.server.network.protocol.request.Request;
+import ch.unibas.dmi.dbis.cs108.casono.server.network.protocol.request.RequestContext;
+
+/**
+ * Request for the `FOLD` command.
+ *
+ * <p>Contains an optional `gameId` when the client targets a specific lobby, otherwise the server
+ * will resolve the lobby from the requesting session's user.
+ */
+public class PlayerFoldRequest extends Request {
+    private final Integer gameId;
+
+    /**
+     * Creates a new {@code PlayerFoldRequest}.
+     *
+     * @param context the request context
+     * @param gameId optional game id of the targeted lobby (may be {@code null})
+     */
+    public PlayerFoldRequest(RequestContext context, Integer gameId) {
+        super(context);
+        this.gameId = gameId;
+    }
+
+    /**
+     * Returns the optional target game id.
+     *
+     * @return the game id or {@code null} if not provided
+     */
+    public Integer getGameId() {
+        return gameId;
+    }
+}

src/main/java/ch/unibas/dmi/dbis/cs108/casono/server/app/commands/game/get_game_state/GetGameStateHandler.java

@@ -0,0 +1,126 @@
+package ch.unibas.dmi.dbis.cs108.casono.server.app.commands.game.get_game_state;
+
+import ch.unibas.dmi.dbis.cs108.casono.server.app.checks.UserLoggedInCheck;
+import ch.unibas.dmi.dbis.cs108.casono.server.domain.game.state.GamePhase;
+import ch.unibas.dmi.dbis.cs108.casono.server.domain.lobby.Lobby;
+import ch.unibas.dmi.dbis.cs108.casono.server.domain.lobby.LobbyId;
+import ch.unibas.dmi.dbis.cs108.casono.server.domain.lobby.LobbyManager;
+import ch.unibas.dmi.dbis.cs108.casono.server.domain.user.User;
+import ch.unibas.dmi.dbis.cs108.casono.server.domain.user.UserRegistry;
+import ch.unibas.dmi.dbis.cs108.casono.server.network.command.execution.CommandHandler;
+import ch.unibas.dmi.dbis.cs108.casono.server.network.protocol.response.ErrorResponse;
+import ch.unibas.dmi.dbis.cs108.casono.server.network.protocol.response.dispatcher.ResponseDispatcher;
+import java.util.concurrent.CompletableFuture;
+import java.util.concurrent.TimeUnit;
+import java.util.logging.Level;
+import java.util.logging.Logger;
+
+/** Handler for GET_GAME_STATE: returns pot, phase, community cards and per-player info. */
+public class GetGameStateHandler extends CommandHandler<GetGameStateRequest> {
+    private static final Logger LOGGER = Logger.getLogger(GetGameStateHandler.class.getName());
+    private static final int FINISHED_CLEANUP_DELAY_SECONDS = 2;
+
+    private final LobbyManager lobbyManager;
+    private final UserRegistry userRegistry;
+
+    public GetGameStateHandler(
+            ResponseDispatcher responseDispatcher,
+            LobbyManager lobbyManager,
+            UserRegistry userRegistry) {
+        super(responseDispatcher);
+        this.lobbyManager = lobbyManager;
+        this.userRegistry = userRegistry;
+        addCheck(new UserLoggedInCheck(userRegistry));
+    }
+
+    @Override
+    public void execute(GetGameStateRequest request) {
+        Integer gameId = request.getGameId();
+        String username = resolveUsername(request);
+
+        Lobby lobby;
+        LobbyId lobbyId;
+        if (gameId != null) {
+            lobbyId = LobbyId.of(gameId);
+            lobby = lobbyManager.getLobby(lobbyId);
+            if (lobby == null) {
+                responseDispatcher.dispatch(
+                        new ErrorResponse(
+                                request.getContext(), "LOBBY_NOT_FOUND", "Lobby not found"));
+                return;
+            }
+        } else {
+            if (username == null) {
+                var maybeUser = userRegistry.getBySessionId(request.getSessionId());
+                if (maybeUser.isEmpty()) {
+                    responseDispatcher.dispatch(
+                            new ErrorResponse(
+                                    request.getContext(), "NOT_LOGGED_IN", "User not logged in"));
+                    return;
+                }
+                User u = maybeUser.get();
+                username = u.getName();
+            }
+
+            lobby = lobbyManager.getLobbyByUsername(username);
+            if (lobby == null) {
+                responseDispatcher.dispatch(
+                        new ErrorResponse(
+                                request.getContext(), "NOT_IN_LOBBY", "User not in a lobby"));
+                return;
+            }
+            lobbyId = lobby.getId();
+        }
+
+        var game = lobby.getGameController();
+        if (game == null) {
+            responseDispatcher.dispatch(
+                    new ErrorResponse(
+                            request.getContext(), "GAME_NOT_STARTED", "Game not started"));
+            return;
+        }
+
+        responseDispatcher.dispatch(new GetGameStateResponse(request.getContext(), game, username));
+
+        if (game.getState().getPhase() == GamePhase.FINISHED) {
+            CompletableFuture.delayedExecutor(FINISHED_CLEANUP_DELAY_SECONDS, TimeUnit.SECONDS)
+                    .execute(() -> cleanupLobby(lobby, lobbyId));
+        }
+    }
+
+    /**
+     * Cleans up a lobby by removing all players and resetting the game controller. This is called
+     * when the game reaches FINISHED phase.
+     */
+    private void cleanupLobby(Lobby lobby, LobbyId lobbyId) {
+        if (lobby == null || lobbyId == null) {
+            return;
+        }
+
+        try {
+            for (String playerName : lobby.getPlayerNames()) {
+                lobbyManager.removePlayer(playerName);
+            }
+            lobby.initGame(null);
+        } catch (RuntimeException e) {
+            LOGGER.log(
+                    Level.WARNING,
+                    "Failed to cleanup lobby " + lobbyId + " during FINISHED state",
+                    e);
+        }
+    }
+
+    private String resolveUsername(GetGameStateRequest request) {
+        String username = request.getUsername();
+        if (username != null && !username.isBlank()) {
+            return username.trim();
+        }
+
+        return userRegistry
+                .getBySessionId(request.getSessionId())
+                .map(User::getName)
+                .map(String::trim)
+                .filter(name -> !name.isEmpty())
+                .orElse(null);
+    }
+}

src/main/java/ch/unibas/dmi/dbis/cs108/casono/server/app/commands/game/get_game_state/GetGameStateParser.java

@@ -0,0 +1,16 @@
+package ch.unibas.dmi.dbis.cs108.casono.server.app.commands.game.get_game_state;
+
+import ch.unibas.dmi.dbis.cs108.casono.server.network.command.parsing.CommandParser;
+import ch.unibas.dmi.dbis.cs108.casono.server.network.protocol.request.PrimitiveRequest;
+import ch.unibas.dmi.dbis.cs108.casono.server.network.protocol.request.accessor.RequestParameterAccessor;
+
+public class GetGameStateParser implements CommandParser<GetGameStateRequest> {
+    @Override
+    public GetGameStateRequest parse(PrimitiveRequest primitiveRequest) {
+        RequestParameterAccessor accessor =
+                new RequestParameterAccessor(primitiveRequest.parameters());
+        Integer gameId = accessor.optional("GAME_ID", null, Integer::parseInt);
+        String username = accessor.optional("USERNAME", null);
+        return new GetGameStateRequest(primitiveRequest.context(), username, gameId);
+    }
+}

src/main/java/ch/unibas/dmi/dbis/cs108/casono/server/app/commands/game/get_game_state/GetGameStateRequest.java

@@ -0,0 +1,31 @@
+package ch.unibas.dmi.dbis.cs108.casono.server.app.commands.game.get_game_state;
+
+import ch.unibas.dmi.dbis.cs108.casono.server.network.protocol.request.Request;
+import ch.unibas.dmi.dbis.cs108.casono.server.network.protocol.request.RequestContext;
+
+/**
+ * Request object for `GET_GAME_STATE`.
+ *
+ * <p>Either `USERNAME` or `GAME_ID` may be provided by the client. If both are omitted the handler
+ * will resolve the username from the session.
+ */
+public class GetGameStateRequest extends Request {
+    private final String username;
+    private final Integer gameId;
+
+    public GetGameStateRequest(RequestContext context, String username, Integer gameId) {
+        super(context);
+        this.username = username;
+        this.gameId = gameId;
+    }
+
+    /** Returns the optional username provided in the request. */
+    public String getUsername() {
+        return username;
+    }
+
+    /** Returns the optional game id provided in the request. */
+    public Integer getGameId() {
+        return gameId;
+    }
+}

src/main/java/ch/unibas/dmi/dbis/cs108/casono/server/app/commands/game/get_game_state/GetGameStateResponse.java

@@ -0,0 +1,235 @@
+package ch.unibas.dmi.dbis.cs108.casono.server.app.commands.game.get_game_state;
+
+import ch.unibas.dmi.dbis.cs108.casono.server.domain.game.GameController;
+import ch.unibas.dmi.dbis.cs108.casono.server.domain.game.deck.Card;
+import ch.unibas.dmi.dbis.cs108.casono.server.domain.game.deck.Rank;
+import ch.unibas.dmi.dbis.cs108.casono.server.domain.game.deck.Suit;
+import ch.unibas.dmi.dbis.cs108.casono.server.domain.game.player.Player;
+import ch.unibas.dmi.dbis.cs108.casono.server.domain.game.player.PlayerId;
+import ch.unibas.dmi.dbis.cs108.casono.server.domain.game.state.GamePhase;
+import ch.unibas.dmi.dbis.cs108.casono.server.domain.game.state.GameState;
+import ch.unibas.dmi.dbis.cs108.casono.server.domain.highscore.HighscoreService;
+import ch.unibas.dmi.dbis.cs108.casono.server.network.protocol.request.RequestContext;
+import ch.unibas.dmi.dbis.cs108.casono.server.network.protocol.response.SuccessResponse;
+import ch.unibas.dmi.dbis.cs108.casono.server.network.protocol.response.builder.ResponseBody;
+import ch.unibas.dmi.dbis.cs108.casono.server.network.protocol.response.builder.ResponseBodyBuilder;
+import java.util.List;
+import java.util.Objects;
+
+/**
+ * Response carrying a snapshot of the current game state using the project's wire format.
+ *
+ * <p>Wire format (relevant parts):
+ *
+ * <p>+OK PHASE=... POT=... CURRENT_BET=... DEALER=... ACTIVE_PLAYER=... CARD VALUE=... SUIT=... END
+ * PLAYER NAME=... CHIPS=... BET=... STATE=... CARD (only for requesting user) VALUE=... SUIT=...
+ * END END END
+ *
+ * <p>Notes: - Community cards are always emitted at top-level (0..5). If none exist (e.g. PREFLOP),
+ * none are emitted. - Hole cards are only emitted for the requesting player (privacy).
+ */
+public class GetGameStateResponse extends SuccessResponse {
+
+    public GetGameStateResponse(
+            RequestContext context, GameController game, String requestingUsername) {
+        super(
+                context,
+                buildBody(
+                        game,
+                        Objects.requireNonNull(game, "game must not be null").getState(),
+                        requestingUsername));
+    }
+
+    private static ResponseBody buildBody(
+            GameController game, GameState state, String requestingUsername) {
+        Objects.requireNonNull(state, "state must not be null");
+
+        ResponseBodyBuilder builder = ResponseBody.builder();
+
+        builder.param("PHASE", state.getPhase() == null ? "UNKNOWN" : state.getPhase().name());
+        builder.param("POT", state.getPot() == null ? 0 : state.getPot().getAmount());
+        builder.param("CURRENT_BET", computeGlobalCurrentBet(state));
+        builder.param("DEALER", state.getDealerIndex());
+        builder.param("ACTIVE_PLAYER", state.getCurrentPlayerIndex());
+        int winnerIndex = computeWinnerIndex(state, game);
+        builder.param("WINNER", winnerIndex);
+
+        appendWinnerToHighscoresIfFinished(state, winnerIndex);
+        appendHighscoreEntries(builder);
+
+        appendCommunityCards(builder, state);
+
+        appendPlayers(builder, state, requestingUsername);
+
+        return builder.build();
+    }
+
+    private static void appendWinnerToHighscoresIfFinished(GameState state, int winnerIndex) {
+        if (winnerIndex < 0 || state.getPhase() != GamePhase.FINISHED) {
+            return;
+        }
+
+        if (!state.tryMarkWinnerPersistedForHand()) {
+            return;
+        }
+
+        Player winner = findPlayerByIndex(state, winnerIndex);
+        if (winner == null || winner.getId() == null || winner.getId().value() == null) {
+            return;
+        }
+
+        HighscoreService.getInstance().appendWinner(winner.getId().value());
+    }
+
+    private static Player findPlayerByIndex(GameState state, int winnerIndex) {
+        int currentIndex = 0;
+        for (Player player : state.getPlayers()) {
+            if (currentIndex == winnerIndex) {
+                return player;
+            }
+            currentIndex++;
+        }
+        return null;
+    }
+
+    private static void appendHighscoreEntries(ResponseBodyBuilder builder) {
+        for (String entry : HighscoreService.getInstance().readFormattedEntries()) {
+            builder.param("HIGHSCORE", entry);
+        }
+    }
+
+    private static int computeWinnerIndex(GameState state, GameController game) {
+        GamePhase phase = state.getPhase();
+        if (phase != GamePhase.SHOWDOWN && phase != GamePhase.FINISHED) {
+            return -1;
+        }
+
+        PlayerId winnerId = game.determineWinner();
+        if (winnerId == null) {
+            return -1;
+        }
+
+        int index = 0;
+        for (Player p : state.getPlayers()) {
+            if (p != null && winnerId.equals(p.getId())) {
+                return index;
+            }
+            index++;
+        }
+
+        return -1;
+    }
+
+    private static int computeGlobalCurrentBet(GameState state) {
+        int globalCurrentBet = 0;
+        for (Player p : state.getPlayers()) {
+            if (p == null) {
+                continue;
+            }
+
+            int b = state.getCurrentBet(p.getId());
+            if (b > globalCurrentBet) {
+                globalCurrentBet = b;
+            }
+        }
+        return globalCurrentBet;
+    }
+
+    private static void appendCommunityCards(ResponseBodyBuilder builder, GameState state) {
+        List<Card> community = state.getCommunityCards();
+
+        if (community == null || community.isEmpty()) {
+            return;
+        }
+
+        for (Card c : community) {
+            if (c == null) {
+                continue;
+            }
+
+            builder.block(
+                    "CARD",
+                    card -> {
+                        card.param("VALUE", rankToWire(c.getRank()));
+                        card.param("SUIT", suitToWire(c.getSuit()));
+                    });
+        }
+    }
+
+    private static void appendPlayers(
+            ResponseBodyBuilder builder, GameState state, String requestingUsername) {
+        String req = (requestingUsername == null) ? null : requestingUsername.trim();
+
+        for (Player p : state.getPlayers()) {
+            if (p == null) {
+                continue;
+            }
+
+            PlayerId pid = p.getId();
+            String name = (pid == null || pid.value() == null) ? "" : pid.value().trim();
+
+            builder.block(
+                    "PLAYER",
+                    pblock -> {
+                        pblock.param("NAME", name);
+                        pblock.param("CHIPS", p.getChips());
+                        pblock.param("BET", pid == null ? 0 : state.getCurrentBet(pid));
+                        pblock.param("STATE", p.isFolded() ? "FOLDED" : "ACTIVE");
+
+                        if (req != null && pid != null && req.equals(name)) {
+                            List<Card> hole = state.getHoleCards(pid);
+
+                            if (hole != null) {
+                                for (Card hc : hole) {
+                                    if (hc == null) {
+                                        continue;
+                                    }
+
+                                    pblock.block(
+                                            "CARD",
+                                            cblock -> {
+                                                cblock.param("VALUE", rankToWire(hc.getRank()));
+                                                cblock.param("SUIT", suitToWire(hc.getSuit()));
+                                            });
+                                }
+                            }
+                        }
+                    });
+        }
+    }
+
+    private static String rankToWire(Rank r) {
+        if (r == null) {
+            return "";
+        }
+
+        return switch (r) {
+            case TWO -> "2";
+            case THREE -> "3";
+            case FOUR -> "4";
+            case FIVE -> "5";
+            case SIX -> "6";
+            case SEVEN -> "7";
+            case EIGHT -> "8";
+            case NINE -> "9";
+            case TEN -> "10";
+            case JACK -> "J";
+            case QUEEN -> "Q";
+            case KING -> "K";
+            case ACE -> "A";
+        };
+    }
+
+    private static String suitToWire(Suit s) {
+        if (s == null) {
+            return "";
+        }
+
+        return switch (s) {
+            case HEARTS -> "H";
+            case DIAMONDS -> "D";
+            case CLUBS -> "C";
+            case SPADES -> "S";
+        };
+    }
+}

src/main/java/ch/unibas/dmi/dbis/cs108/casono/server/app/commands/game/raise/PlayerRaiseHandler.java

@@ -0,0 +1,104 @@
+package ch.unibas.dmi.dbis.cs108.casono.server.app.commands.game.raise;
+
+import ch.unibas.dmi.dbis.cs108.casono.server.app.checks.GameLobbyExistsCheck;
+import ch.unibas.dmi.dbis.cs108.casono.server.app.checks.UserLoggedInCheck;
+import ch.unibas.dmi.dbis.cs108.casono.server.domain.game.GameController;
+import ch.unibas.dmi.dbis.cs108.casono.server.domain.game.player.PlayerId;
+import ch.unibas.dmi.dbis.cs108.casono.server.domain.lobby.Lobby;
+import ch.unibas.dmi.dbis.cs108.casono.server.domain.lobby.LobbyId;
+import ch.unibas.dmi.dbis.cs108.casono.server.domain.lobby.LobbyManager;
+import ch.unibas.dmi.dbis.cs108.casono.server.domain.user.User;
+import ch.unibas.dmi.dbis.cs108.casono.server.domain.user.UserRegistry;
+import ch.unibas.dmi.dbis.cs108.casono.server.network.command.execution.CommandHandler;
+import ch.unibas.dmi.dbis.cs108.casono.server.network.protocol.response.ErrorResponse;
+import ch.unibas.dmi.dbis.cs108.casono.server.network.protocol.response.OkResponse;
+import ch.unibas.dmi.dbis.cs108.casono.server.network.protocol.response.dispatcher.ResponseDispatcher;
+import java.util.Optional;
+
+/**
+ * Handler for the `RAISE` command.
+ *
+ * <p>This handler validates the request (amount >= 0), resolves the user and target lobby (by
+ * `GAME_ID` when provided or by session username otherwise), checks that a game is running and then
+ * forwards the action to the {@code GameController}.
+ *
+ * <p>On failure the handler dispatches an {@link ErrorResponse} with an appropriate error code
+ * (e.g. {@code INVALID_AMOUNT}, {@code NOT_IN_LOBBY}, {@code LOBBY_NOT_FOUND}, {@code
+ * GAME_NOT_STARTED}, {@code GAME_ACTION_FAILED}). On success it dispatches an {@link OkResponse}.
+ */
+public class PlayerRaiseHandler extends CommandHandler<PlayerRaiseRequest> {
+    private final UserRegistry userRegistry;
+    private final LobbyManager lobbyManager;
+
+    /**
+     * Creates a new {@code PlayerRaiseHandler}.
+     *
+     * @param responseDispatcher dispatcher used to send responses back to the client
+     * @param userRegistry registry to resolve users from session ids
+     * @param lobbyManager manager used to lookup lobbies and their game controllers
+     */
+    public PlayerRaiseHandler(
+            ResponseDispatcher responseDispatcher,
+            UserRegistry userRegistry,
+            LobbyManager lobbyManager) {
+        super(responseDispatcher);
+        this.userRegistry = userRegistry;
+        this.lobbyManager = lobbyManager;
+        addCheck(new UserLoggedInCheck(userRegistry));
+        addCheck(new GameLobbyExistsCheck(userRegistry, lobbyManager));
+    }
+
+    /**
+     * Execute the raise request: validate parameters, resolve lobby and game, and forward the raise
+     * action to the game controller. Sends an {@link ErrorResponse} on failure or an {@link
+     * OkResponse} on success.
+     *
+     * @param request the parsed {@link PlayerRaiseRequest}
+     */
+    @Override
+    public void execute(PlayerRaiseRequest request) {
+        int amount = request.getAmount();
+
+        if (amount < 0) {
+            responseDispatcher.dispatch(
+                    new ErrorResponse(
+                            request.getContext(), "INVALID_AMOUNT", "Amount must be non-negative"));
+            return;
+        }
+
+        Optional<User> opt = userRegistry.getBySessionId(request.getSessionId());
+        if (opt.isEmpty()) {
+            responseDispatcher.dispatch(
+                    new ErrorResponse(request.getContext(), "NOT_LOGGED_IN", "User not logged in"));
+            return;
+        }
+
+        String username = opt.get().getName();
+
+        Integer gameId = request.getGameId();
+        Lobby lobby;
+        if (gameId != null) {
+            lobby = lobbyManager.getLobby(LobbyId.of(gameId));
+        } else {
+            lobby = lobbyManager.getLobbyByUsername(username);
+        }
+
+        GameController game = lobby.getGameController();
+        if (game == null) {
+            responseDispatcher.dispatch(
+                    new ErrorResponse(
+                            request.getContext(), "GAME_NOT_STARTED", "Game not started"));
+            return;
+        }
+
+        try {
+            game.playerRaise(PlayerId.of(username), amount);
+        } catch (RuntimeException e) {
+            responseDispatcher.dispatch(
+                    new ErrorResponse(request.getContext(), "GAME_ACTION_FAILED", e.getMessage()));
+            return;
+        }
+
+        responseDispatcher.dispatch(new OkResponse(request.getContext()));
+    }
+}

src/main/java/ch/unibas/dmi/dbis/cs108/casono/server/app/commands/game/raise/PlayerRaiseParser.java

@@ -0,0 +1,34 @@
+package ch.unibas.dmi.dbis.cs108.casono.server.app.commands.game.raise;
+
+import ch.unibas.dmi.dbis.cs108.casono.server.network.command.parsing.CommandParser;
+import ch.unibas.dmi.dbis.cs108.casono.server.network.protocol.request.PrimitiveRequest;
+import ch.unibas.dmi.dbis.cs108.casono.server.network.protocol.request.accessor.RequestParameterAccessor;
+
+/**
+ * Parser for the `RAISE` command.
+ *
+ * <p>Parses the request parameters and builds a {@link PlayerRaiseRequest}. Expected parameters:
+ *
+ * <ul>
+ *   <li>`GAME_ID` (optional) - numeric id of the lobby/game to target
+ *   <li>`AMOUNT` (required) - amount to raise
+ * </ul>
+ */
+public class PlayerRaiseParser implements CommandParser<PlayerRaiseRequest> {
+    @Override
+    public PlayerRaiseRequest parse(PrimitiveRequest primitiveRequest) {
+        RequestParameterAccessor accessor =
+                new RequestParameterAccessor(primitiveRequest.parameters());
+
+        Integer gameId = null;
+        try {
+            gameId = accessor.optional("GAME_ID", null, Integer::parseInt);
+        } catch (Exception e) {
+            // parse handled by framework
+        }
+
+        int amount = accessor.require("AMOUNT", Integer::parseInt);
+
+        return new PlayerRaiseRequest(primitiveRequest.context(), gameId, amount);
+    }
+}

src/main/java/ch/unibas/dmi/dbis/cs108/casono/server/app/commands/game/raise/PlayerRaiseRequest.java

@@ -0,0 +1,45 @@
+package ch.unibas.dmi.dbis.cs108.casono.server.app.commands.game.raise;
+
+import ch.unibas.dmi.dbis.cs108.casono.server.network.protocol.request.Request;
+import ch.unibas.dmi.dbis.cs108.casono.server.network.protocol.request.RequestContext;
+
+/**
+ * Request for the `RAISE` command.
+ *
+ * <p>Contains the optional target `gameId` and the `amount` the player wants to raise.
+ */
+public class PlayerRaiseRequest extends Request {
+    private final Integer gameId;
+    private final int amount;
+
+    /**
+     * Creates a new {@code PlayerRaiseRequest}.
+     *
+     * @param context the request context
+     * @param gameId optional game id of the targeted lobby (may be {@code null})
+     * @param amount the raise amount (non-negative)
+     */
+    public PlayerRaiseRequest(RequestContext context, Integer gameId, int amount) {
+        super(context);
+        this.gameId = gameId;
+        this.amount = amount;
+    }
+
+    /**
+     * Returns the optional target game id.
+     *
+     * @return the game id or {@code null} if not provided
+     */
+    public Integer getGameId() {
+        return gameId;
+    }
+
+    /**
+     * Returns the requested raise amount.
+     *
+     * @return the raise amount
+     */
+    public int getAmount() {
+        return amount;
+    }
+}

src/main/java/ch/unibas/dmi/dbis/cs108/casono/server/app/commands/get_message_count/GetMessageCountHandler.java

@@ -0,0 +1,49 @@
+package ch.unibas.dmi.dbis.cs108.casono.server.app.commands.get_message_count;
+
+import ch.unibas.dmi.dbis.cs108.casono.server.domain.user.User;
+import ch.unibas.dmi.dbis.cs108.casono.server.domain.user.UserRegistry;
+import ch.unibas.dmi.dbis.cs108.casono.server.network.command.execution.CommandHandler;
+import ch.unibas.dmi.dbis.cs108.casono.server.network.protocol.response.ErrorResponse;
+import ch.unibas.dmi.dbis.cs108.casono.server.network.protocol.response.dispatcher.ResponseDispatcher;
+import java.util.Optional;
+
+public class GetMessageCountHandler extends CommandHandler<GetMessageCountRequest> {
+    private final UserRegistry userRegistry;
+
+    /**
+     * Constructs a new GetMessageCountHandler with the necessary response dispatcher and user
+     * registry.
+     *
+     * @param responseDispatcher The dispatcher used to send the count or error back to the client.
+     * @param userRegistry The registry used to identify the user and access their message queue.
+     */
+    public GetMessageCountHandler(
+            ResponseDispatcher responseDispatcher, UserRegistry userRegistry) {
+        super(responseDispatcher);
+        this.userRegistry = userRegistry;
+    }
+
+    /**
+     * Processes a request to retrieve the number of pending messages for a user. It looks up the
+     * user by their session ID; if found, it dispatches a {@link GetMessageCountResponse}
+     * containing the current count. Otherwise, it dispatches an {@link ErrorResponse}.
+     *
+     * @param request The {@link GetMessageCountRequest} containing the session details.
+     */
+    @Override
+    public void execute(GetMessageCountRequest request) {
+        Optional<User> user = userRegistry.getBySessionId(request.getSessionId());
+        if (user.isPresent()) {
+            int count = user.get().getMessageCount();
+            GetMessageCountResponse response =
+                    new GetMessageCountResponse(request.getContext(), count);
+            responseDispatcher.dispatch(response);
+        } else {
+            ErrorResponse response =
+                    new ErrorResponse(
+                            request.getContext(), "", "user could not be identified by SessionId");
+
+            responseDispatcher.dispatch(response);
+        }
+    }
+}

src/main/java/ch/unibas/dmi/dbis/cs108/casono/server/app/commands/get_message_count/GetMessageCountParser.java

@@ -0,0 +1,22 @@
+package ch.unibas.dmi.dbis.cs108.casono.server.app.commands.get_message_count;
+
+import ch.unibas.dmi.dbis.cs108.casono.server.network.command.parsing.CommandParser;
+import ch.unibas.dmi.dbis.cs108.casono.server.network.protocol.request.PrimitiveRequest;
+import ch.unibas.dmi.dbis.cs108.casono.server.network.protocol.request.accessor.RequestParameterAccessor;
+
+public class GetMessageCountParser implements CommandParser<GetMessageCountRequest> {
+    /**
+     * Parses a raw {@link PrimitiveRequest} into a {@link GetMessageCountRequest}. This method
+     * wraps the request context from the network layer into a structured message count request
+     * object.
+     *
+     * @param primitiveRequest The raw request containing parameters and context from the network.
+     * @return A new {@link GetMessageCountRequest} instance.
+     */
+    @Override
+    public GetMessageCountRequest parse(PrimitiveRequest primitiveRequest) {
+        RequestParameterAccessor accessor =
+                new RequestParameterAccessor(primitiveRequest.parameters());
+        return new GetMessageCountRequest(primitiveRequest.context());
+    }
+}

src/main/java/ch/unibas/dmi/dbis/cs108/casono/server/app/commands/get_message_count/GetMessageCountRequest.java

@@ -0,0 +1,17 @@
+package ch.unibas.dmi.dbis.cs108.casono.server.app.commands.get_message_count;
+
+import ch.unibas.dmi.dbis.cs108.casono.server.network.protocol.request.Request;
+import ch.unibas.dmi.dbis.cs108.casono.server.network.protocol.request.RequestContext;
+
+public class GetMessageCountRequest extends Request {
+    /**
+     * Constructs a new GetMessageCountRequest with the specified request context. This request is
+     * used by a client to query the number of pending messages currently waiting in their
+     * server-side queue.
+     *
+     * @param context The {@link RequestContext} associated with this request.
+     */
+    public GetMessageCountRequest(RequestContext context) {
+        super(context);
+    }
+}

src/main/java/ch/unibas/dmi/dbis/cs108/casono/server/app/commands/get_message_count/GetMessageCountResponse.java

@@ -0,0 +1,18 @@
+package ch.unibas.dmi.dbis.cs108.casono.server.app.commands.get_message_count;
+
+import ch.unibas.dmi.dbis.cs108.casono.server.network.protocol.request.RequestContext;
+import ch.unibas.dmi.dbis.cs108.casono.server.network.protocol.response.SuccessResponse;
+import ch.unibas.dmi.dbis.cs108.casono.server.network.protocol.response.builder.ResponseBodyBuilder;
+
+public class GetMessageCountResponse extends SuccessResponse {
+    /**
+     * Constructs a new GetMessageCountResponse. It creates a response body containing the "COUNT"
+     * parameter and associates it with the original request context.
+     *
+     * @param context The {@link RequestContext} of the original request.
+     * @param count The number of pending messages to be returned to the client.
+     */
+    public GetMessageCountResponse(RequestContext context, int count) {
+        super(context, new ResponseBodyBuilder().param("COUNT", count).build());
+    }
+}

src/main/java/ch/unibas/dmi/dbis/cs108/casono/server/app/commands/get_next_message/GetNextMessageHandler.java

@@ -0,0 +1,49 @@
+package ch.unibas.dmi.dbis.cs108.casono.server.app.commands.get_next_message;
+
+import ch.unibas.dmi.dbis.cs108.casono.client.chat.Message;
+import ch.unibas.dmi.dbis.cs108.casono.server.domain.user.User;
+import ch.unibas.dmi.dbis.cs108.casono.server.domain.user.UserRegistry;
+import ch.unibas.dmi.dbis.cs108.casono.server.network.command.execution.CommandHandler;
+import ch.unibas.dmi.dbis.cs108.casono.server.network.protocol.response.ErrorResponse;
+import ch.unibas.dmi.dbis.cs108.casono.server.network.protocol.response.dispatcher.ResponseDispatcher;
+import java.util.Optional;
+
+public class GetNextMessageHandler extends CommandHandler<GetNextMessageRequest> {
+    private final UserRegistry userRegistry;
+
+    /**
+     * Constructs a new GetNextMessageHandler with the required dispatcher and user registry.
+     *
+     * @param responseDispatcher The dispatcher used to send responses back to clients.
+     * @param userRegistry The registry used to look up users by their session information.
+     */
+    public GetNextMessageHandler(ResponseDispatcher responseDispatcher, UserRegistry userRegistry) {
+        super(responseDispatcher);
+        this.userRegistry = userRegistry;
+    }
+
+    /**
+     * Executes the request to retrieve the next message for a specific user. It identifies the user
+     * via their session ID, dequeues the next available message, and dispatches a {@link
+     * GetNextMessageResponse}. If the user cannot be identified, an {@link ErrorResponse} is sent
+     * instead.
+     *
+     * @param request The {@link GetNextMessageRequest} containing the session and context.
+     */
+    @Override
+    public void execute(GetNextMessageRequest request) {
+        Optional<User> user = userRegistry.getBySessionId(request.getSessionId());
+        if (user.isPresent()) {
+            Message msg = user.get().dequeMessage();
+            GetNextMessageResponse response = new GetNextMessageResponse(request.getContext(), msg);
+            responseDispatcher.dispatch(response);
+        } else {
+            ErrorResponse response =
+                    new ErrorResponse(
+                            request.getContext(),
+                            "NO_USER_ASSOCIATED",
+                            "user could not be identified by SessionId");
+            responseDispatcher.dispatch(response);
+        }
+    }
+}

src/main/java/ch/unibas/dmi/dbis/cs108/casono/server/app/commands/get_next_message/GetNextMessageParser.java

@@ -0,0 +1,22 @@
+package ch.unibas.dmi.dbis.cs108.casono.server.app.commands.get_next_message;
+
+import ch.unibas.dmi.dbis.cs108.casono.server.network.command.parsing.CommandParser;
+import ch.unibas.dmi.dbis.cs108.casono.server.network.protocol.request.PrimitiveRequest;
+import ch.unibas.dmi.dbis.cs108.casono.server.network.protocol.request.accessor.RequestParameterAccessor;
+
+public class GetNextMessageParser implements CommandParser<GetNextMessageRequest> {
+    /**
+     * Parses a raw {@link PrimitiveRequest} into a {@link GetNextMessageRequest}. This method
+     * initializes a parameter accessor (though not currently used for extraction) and returns a
+     * structured request object containing the original request context.
+     *
+     * @param primitiveRequest The raw request containing parameters and context from the network.
+     * @return A new {@link GetNextMessageRequest} instance.
+     */
+    @Override
+    public GetNextMessageRequest parse(PrimitiveRequest primitiveRequest) {
+        RequestParameterAccessor accessor =
+                new RequestParameterAccessor(primitiveRequest.parameters());
+        return new GetNextMessageRequest(primitiveRequest.context());
+    }
+}

src/main/java/ch/unibas/dmi/dbis/cs108/casono/server/app/commands/get_next_message/GetNextMessageRequest.java

@@ -0,0 +1,17 @@
+package ch.unibas.dmi.dbis.cs108.casono.server.app.commands.get_next_message;
+
+import ch.unibas.dmi.dbis.cs108.casono.server.network.protocol.request.Request;
+import ch.unibas.dmi.dbis.cs108.casono.server.network.protocol.request.RequestContext;
+
+public class GetNextMessageRequest extends Request {
+    /**
+     * Constructs a new GetNextMessageRequest with the specified request context. This request is
+     * typically used by a client to poll or retrieve the next available message from the server's
+     * queue.
+     *
+     * @param context The {@link RequestContext} associated with this request.
+     */
+    public GetNextMessageRequest(RequestContext context) {
+        super(context);
+    }
+}

src/main/java/ch/unibas/dmi/dbis/cs108/casono/server/app/commands/get_next_message/GetNextMessageResponse.java

@@ -0,0 +1,19 @@
+package ch.unibas.dmi.dbis.cs108.casono.server.app.commands.get_next_message;
+
+import ch.unibas.dmi.dbis.cs108.casono.client.chat.Message;
+import ch.unibas.dmi.dbis.cs108.casono.server.network.protocol.request.RequestContext;
+import ch.unibas.dmi.dbis.cs108.casono.server.network.protocol.response.SuccessResponse;
+import ch.unibas.dmi.dbis.cs108.casono.server.network.protocol.response.builder.ResponseBody;
+
+public class GetNextMessageResponse extends SuccessResponse {
+    /**
+     * Constructs a new GetNextMessageResponse. It converts the provided {@link Message} into a
+     * network-compatible response body and associates it with the original request context.
+     *
+     * @param context The {@link RequestContext} of the request being answered.
+     * @param msg The {@link Message} to be sent back to the client.
+     */
+    public GetNextMessageResponse(RequestContext context, Message msg) {
+        super(context, msg.toResponse(ResponseBody.builder()));
+    }
+}

src/main/java/ch/unibas/dmi/dbis/cs108/casono/server/app/commands/highscore/clear_highscores/ClearHighscoresHandler.java

@@ -0,0 +1,22 @@
+package ch.unibas.dmi.dbis.cs108.casono.server.app.commands.highscore.clear_highscores;
+
+import ch.unibas.dmi.dbis.cs108.casono.server.domain.highscore.HighscoreService;
+import ch.unibas.dmi.dbis.cs108.casono.server.network.command.execution.CommandHandler;
+import ch.unibas.dmi.dbis.cs108.casono.server.network.protocol.response.OkResponse;
+import ch.unibas.dmi.dbis.cs108.casono.server.network.protocol.response.dispatcher.ResponseDispatcher;
+
+/** Handler for CLEAR_HIGHSCORES. */
+public class ClearHighscoresHandler extends CommandHandler<ClearHighscoresRequest> {
+    private final HighscoreService highscoreService;
+
+    public ClearHighscoresHandler(ResponseDispatcher responseDispatcher) {
+        super(responseDispatcher);
+        this.highscoreService = HighscoreService.getInstance();
+    }
+
+    @Override
+    public void execute(ClearHighscoresRequest request) {
+        highscoreService.clearAll();
+        responseDispatcher.dispatch(new OkResponse(request.getContext()));
+    }
+}

src/main/java/ch/unibas/dmi/dbis/cs108/casono/server/app/commands/highscore/clear_highscores/ClearHighscoresParser.java

@@ -0,0 +1,12 @@
+package ch.unibas.dmi.dbis.cs108.casono.server.app.commands.highscore.clear_highscores;
+
+import ch.unibas.dmi.dbis.cs108.casono.server.network.command.parsing.CommandParser;
+import ch.unibas.dmi.dbis.cs108.casono.server.network.protocol.request.PrimitiveRequest;
+
+/** Parser for CLEAR_HIGHSCORES. */
+public class ClearHighscoresParser implements CommandParser<ClearHighscoresRequest> {
+    @Override
+    public ClearHighscoresRequest parse(PrimitiveRequest primitiveRequest) {
+        return new ClearHighscoresRequest(primitiveRequest.context());
+    }
+}