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

@@ -27,6 +27,12 @@ import ch.unibas.dmi.dbis.cs108.casono.server.app.commands.get_message_count.Get
 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;
@@ -249,6 +255,18 @@ public class ServerApp {
                         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(

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());
+    }
+}

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

@@ -0,0 +1,11 @@
+package ch.unibas.dmi.dbis.cs108.casono.server.app.commands.highscore.clear_highscores;
+
+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 CLEAR_HIGHSCORES. */
+public class ClearHighscoresRequest extends Request {
+    public ClearHighscoresRequest(RequestContext context) {
+        super(context);
+    }
+}

src/main/java/ch/unibas/dmi/dbis/cs108/casono/server/app/commands/highscore/get_highscores/GetHighscoresHandler.java

@@ -0,0 +1,22 @@
+package ch.unibas.dmi.dbis.cs108.casono.server.app.commands.highscore.get_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.dispatcher.ResponseDispatcher;
+
+/** Handler for GET_HIGHSCORES. */
+public class GetHighscoresHandler extends CommandHandler<GetHighscoresRequest> {
+    private final HighscoreService highscoreService;
+
+    public GetHighscoresHandler(ResponseDispatcher responseDispatcher) {
+        super(responseDispatcher);
+        this.highscoreService = HighscoreService.getInstance();
+    }
+
+    @Override
+    public void execute(GetHighscoresRequest request) {
+        responseDispatcher.dispatch(
+                new GetHighscoresResponse(
+                        request.getContext(), highscoreService.readFormattedEntries()));
+    }
+}

src/main/java/ch/unibas/dmi/dbis/cs108/casono/server/app/commands/highscore/get_highscores/GetHighscoresParser.java

@@ -0,0 +1,12 @@
+package ch.unibas.dmi.dbis.cs108.casono.server.app.commands.highscore.get_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 GET_HIGHSCORES. */
+public class GetHighscoresParser implements CommandParser<GetHighscoresRequest> {
+    @Override
+    public GetHighscoresRequest parse(PrimitiveRequest primitiveRequest) {
+        return new GetHighscoresRequest(primitiveRequest.context());
+    }
+}

src/main/java/ch/unibas/dmi/dbis/cs108/casono/server/app/commands/highscore/get_highscores/GetHighscoresRequest.java

@@ -0,0 +1,11 @@
+package ch.unibas.dmi.dbis.cs108.casono.server.app.commands.highscore.get_highscores;
+
+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_HIGHSCORES. */
+public class GetHighscoresRequest extends Request {
+    public GetHighscoresRequest(RequestContext context) {
+        super(context);
+    }
+}

src/main/java/ch/unibas/dmi/dbis/cs108/casono/server/app/commands/highscore/get_highscores/GetHighscoresResponse.java

@@ -0,0 +1,23 @@
+package ch.unibas.dmi.dbis.cs108.casono.server.app.commands.highscore.get_highscores;
+
+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 java.util.List;
+
+/** Success response containing repeated HIGHSCORE parameters. */
+public class GetHighscoresResponse extends SuccessResponse {
+    public GetHighscoresResponse(RequestContext context, List<String> entries) {
+        super(
+                context,
+                ResponseBody.builder()
+                        .block(
+                                "HIGHSCORES",
+                                block -> {
+                                    for (String entry : entries) {
+                                        block.param("HIGHSCORE", entry);
+                                    }
+                                })
+                        .build());
+    }
+}

src/main/java/ch/unibas/dmi/dbis/cs108/casono/server/domain/highscore/HighscoreService.java

@@ -0,0 +1,107 @@
+package ch.unibas.dmi.dbis.cs108.casono.server.domain.highscore;
+
+import java.io.IOException;
+import java.nio.charset.StandardCharsets;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.nio.file.StandardOpenOption;
+import java.time.Instant;
+import java.time.ZoneId;
+import java.time.format.DateTimeFormatter;
+import java.util.ArrayList;
+import java.util.List;
+
+/** Stores and reads persistent highscore entries in timestamp + winner format. */
+public final class HighscoreService {
+
+    private static final HighscoreService INSTANCE = new HighscoreService();
+    private static final DateTimeFormatter DISPLAY_FORMATTER =
+            DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss").withZone(ZoneId.systemDefault());
+    private static final int MAX_RETURNED_ENTRIES = 100;
+    private static final String LINE_SEPARATOR = "\t";
+
+    private final Path storagePath;
+
+    private HighscoreService() {
+        this.storagePath =
+                Path.of(System.getProperty("user.home"), ".casono", "highscores", "winners.log");
+    }
+
+    public static HighscoreService getInstance() {
+        return INSTANCE;
+    }
+
+    public synchronized void appendWinner(String winnerName) {
+        if (winnerName == null) {
+            return;
+        }
+
+        String sanitized = sanitizeName(winnerName);
+        if (sanitized.isEmpty()) {
+            return;
+        }
+
+        String line = Instant.now() + LINE_SEPARATOR + sanitized + System.lineSeparator();
+
+        try {
+            Files.createDirectories(storagePath.getParent());
+            Files.writeString(
+                    storagePath,
+                    line,
+                    StandardCharsets.UTF_8,
+                    StandardOpenOption.CREATE,
+                    StandardOpenOption.APPEND);
+        } catch (IOException ignored) {
+            // Highscore persistence must never break the game state response path.
+        }
+    }
+
+    public synchronized List<String> readFormattedEntries() {
+        if (!Files.exists(storagePath)) {
+            return List.of();
+        }
+
+        List<String> lines;
+        try {
+            lines = Files.readAllLines(storagePath, StandardCharsets.UTF_8);
+        } catch (IOException ignored) {
+            return List.of();
+        }
+
+        List<String> formatted = new ArrayList<>();
+
+        for (String raw : lines) {
+            if (raw == null || raw.isBlank()) {
+                continue;
+            }
+
+            String[] parts = raw.split(LINE_SEPARATOR, 2);
+            if (parts.length < 2) {
+                continue;
+            }
+
+            try {
+                Instant ts = Instant.parse(parts[0].trim());
+                String display = DISPLAY_FORMATTER.format(ts) + " | " + parts[1].trim();
+                formatted.add(display);
+            } catch (Exception ignored) {
+                // Skip malformed lines and keep all valid entries.
+            }
+        }
+
+        int from = Math.max(0, formatted.size() - MAX_RETURNED_ENTRIES);
+        return new ArrayList<>(formatted.subList(from, formatted.size()));
+    }
+
+    public synchronized void clearAll() {
+        try {
+            Files.deleteIfExists(storagePath);
+        } catch (IOException ignored) {
+            // Clearing highscores must not break request handling.
+        }
+    }
+
+    private static String sanitizeName(String winnerName) {
+        return winnerName.trim().replace("\n", " ").replace("\r", " ").replace("\t", " ");
+    }
+}