src/main/java/ch/unibas/dmi/dbis/cs108/casono/server/app/commands/lobby/get_lobby_status/GetLobbyStatusHandler.java

@@ -0,0 +1,62 @@
+package ch.unibas.dmi.dbis.cs108.casono.server.app.commands.lobby.get_lobby_status;
+
+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.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;
+
+/** Handler for GET_LOBBY_STATUS: returns lobby details and player list. */
+public class GetLobbyStatusHandler extends CommandHandler<GetLobbyStatusRequest> {
+    private final LobbyManager lobbyManager;
+    private final UserRegistry userRegistry;
+
+    public GetLobbyStatusHandler(
+            ResponseDispatcher responseDispatcher,
+            LobbyManager lobbyManager,
+            UserRegistry userRegistry) {
+        super(responseDispatcher);
+        this.lobbyManager = lobbyManager;
+        this.userRegistry = userRegistry;
+
+        // Only require logged-in session if the request does not provide an explicit ID
+        // or USERNAME
+        addCheck(
+                request -> {
+                    if (!(request instanceof GetLobbyStatusRequest)) {
+                        return Optional.empty();
+                    }
+                    GetLobbyStatusRequest r = (GetLobbyStatusRequest) request;
+                    if (r.getId() != null || r.getUsername() != null) {
+                        return Optional.empty();
+                    }
+                    var maybeUser = userRegistry.getBySessionId(r.getSessionId());
+                    if (maybeUser.isPresent()) {
+                        return Optional.empty();
+                    }
+                    return Optional.of(
+                            new ErrorResponse(
+                                    r.getContext(),
+                                    "USER_NOT_LOGGED_IN",
+                                    "Request requires an associated logged-in user"));
+                });
+    }
+
+    @Override
+    public void execute(GetLobbyStatusRequest request) {
+        var lobby =
+                (request.getId() != null)
+                        ? lobbyManager.getLobby(LobbyId.of(request.getId()))
+                        : lobbyManager.getLobbyByUsername(request.getUsername());
+
+        if (lobby == null) {
+            responseDispatcher.dispatch(
+                    new ErrorResponse(request.getContext(), "LOBBY_NOT_FOUND", "Lobby not found"));
+            return;
+        }
+
+        responseDispatcher.dispatch(new GetLobbyStatusResponse(request.getContext(), lobby));
+    }
+}

src/main/java/ch/unibas/dmi/dbis/cs108/casono/server/app/commands/lobby/get_lobby_status/GetLobbyStatusParser.java

@@ -0,0 +1,21 @@
+package ch.unibas.dmi.dbis.cs108.casono.server.app.commands.lobby.get_lobby_status;
+
+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 GetLobbyStatusParser implements CommandParser<GetLobbyStatusRequest> {
+    @Override
+    public GetLobbyStatusRequest parse(PrimitiveRequest primitiveRequest) {
+        RequestParameterAccessor accessor =
+                new RequestParameterAccessor(primitiveRequest.parameters());
+        Integer id = null;
+        try {
+            id = accessor.optional("ID", null, Integer::parseInt);
+        } catch (Exception e) {
+            // parse error handled elsewhere
+        }
+        String username = accessor.optional("USERNAME", null);
+        return new GetLobbyStatusRequest(primitiveRequest.context(), id, username);
+    }
+}

src/main/java/ch/unibas/dmi/dbis/cs108/casono/server/app/commands/lobby/get_lobby_status/GetLobbyStatusRequest.java

@@ -0,0 +1,23 @@
+package ch.unibas.dmi.dbis.cs108.casono.server.app.commands.lobby.get_lobby_status;
+
+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 GetLobbyStatusRequest extends Request {
+    private final Integer id;
+    private final String username;
+
+    public GetLobbyStatusRequest(RequestContext context, Integer id, String username) {
+        super(context);
+        this.id = id;
+        this.username = username;
+    }
+
+    public Integer getId() {
+        return id;
+    }
+
+    public String getUsername() {
+        return username;
+    }
+}

src/main/java/ch/unibas/dmi/dbis/cs108/casono/server/app/commands/lobby/get_lobby_status/GetLobbyStatusResponse.java

@@ -0,0 +1,34 @@
+package ch.unibas.dmi.dbis.cs108.casono.server.app.commands.lobby.get_lobby_status;
+
+import ch.unibas.dmi.dbis.cs108.casono.server.domain.lobby.Lobby;
+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;
+
+/** Response with lobby player listing and simple READY placeholders. */
+public class GetLobbyStatusResponse extends SuccessResponse {
+    public GetLobbyStatusResponse(RequestContext context, Lobby lobby) {
+        super(
+                context,
+                ResponseBody.builder()
+                        .block(
+                                "LOBBY",
+                                lb -> {
+                                    lb.param("ID", lobby.getId().value());
+                                    lb.param("NAME", lobby.getName());
+                                    lb.block(
+                                            "PLAYERS",
+                                            players -> {
+                                                for (String p : lobby.getPlayerNames()) {
+                                                    players.block(
+                                                            "PLAYER",
+                                                            pb -> {
+                                                                pb.param("USERNAME", p);
+                                                                pb.param("READY", "false");
+                                                            });
+                                                }
+                                            });
+                                })
+                        .build());
+    }
+}