Enhance GameService.join_game for reconnection support (GS-004)

Add pending forced action and game_over fields to GameJoinResult:
- pending_forced_action: Included when player must complete a forced
  action (e.g., select new active after KO). Essential for reconnection
  so client knows what action is required.
- game_over: Boolean indicating if game has already ended.
- is_your_turn: Now True when player has pending forced action, even if
  it's technically opponent's turn.

The join_game method now handles both initial joins and reconnections
(resume). The last_event_id parameter is accepted for future event
replay support.

Tests: 4 new tests for forced action handling and game_over flag.
Total 51 tests for GameService.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

backend/app/services/game_service.py

@@ -209,14 +209,19 @@ class GameActionResult:
 
 @dataclass
 class GameJoinResult:
-    """Result of joining a game.
+    """Result of joining or rejoining a game.
+
+    Used when a player connects/reconnects to a game session. Contains
+    everything needed to render the game UI and know what action is required.
 
     Attributes:
         success: Whether the join succeeded.
         game_id: The game ID.
         player_id: The joining player's ID.
         visible_state: The game state visible to the player.
-        is_your_turn: Whether it's this player's turn.
+        is_your_turn: Whether it's this player's turn (or forced action required).
+        game_over: Whether the game has already ended.
+        pending_forced_action: If set, this action must be taken before any other.
         message: Additional information or error message.
     """
 
@@ -225,6 +230,8 @@ class GameJoinResult:
     player_id: str
     visible_state: VisibleGameState | None = None
     is_your_turn: bool = False
+    game_over: bool = False
+    pending_forced_action: PendingForcedAction | None = None
     message: str = ""
 
 
@@ -436,13 +443,18 @@ class GameService:
         Loads the game state and returns the player's visible view.
         Used when a player connects or reconnects to a game.
 
+        This method handles both initial joins and reconnections after
+        disconnect. On reconnect, the full current state is returned
+        including any pending forced actions that the player must complete.
+
         Args:
             game_id: The game to join.
             player_id: The joining player's ID.
             last_event_id: Last event ID for reconnection replay (future use).
+                Will be used to replay missed events after reconnect.
 
         Returns:
-            GameJoinResult with the visible state.
+            GameJoinResult with the visible state and any pending actions.
         """
         try:
             state = await self.get_game_state(game_id)
@@ -462,19 +474,37 @@ class GameService:
                 message="You are not a participant in this game",
             )
 
+        visible = get_visible_state(state, player_id)
+
         # Check if game already ended
         if state.winner_id is not None or state.end_reason is not None:
-            visible = get_visible_state(state, player_id)
+            logger.info(f"Player {player_id} joined ended game {game_id}")
             return GameJoinResult(
                 success=True,
                 game_id=game_id,
                 player_id=player_id,
                 visible_state=visible,
                 is_your_turn=False,
+                game_over=True,
                 message="Game has ended",
             )
 
-        visible = get_visible_state(state, player_id)
+        # Check for pending forced action
+        forced = state.get_current_forced_action()
+        pending_forced: PendingForcedAction | None = None
+        if forced is not None:
+            pending_forced = PendingForcedAction(
+                player_id=forced.player_id,
+                action_type=forced.action_type,
+                reason=forced.reason,
+                params=forced.params or {},
+            )
+
+        # Determine if it's this player's turn
+        # It's their turn if: normal turn OR they have a forced action
+        is_turn = state.current_player_id == player_id
+        if forced is not None and forced.player_id == player_id:
+            is_turn = True
 
         logger.info(f"Player {player_id} joined game {game_id}")
 
@@ -483,7 +513,9 @@ class GameService:
             game_id=game_id,
             player_id=player_id,
             visible_state=visible,
-            is_your_turn=state.current_player_id == player_id,
+            is_your_turn=is_turn,
+            game_over=False,
+            pending_forced_action=pending_forced,
         )
 
     async def execute_action(

backend/project_plans/PHASE_4_GAME_SERVICE.json

@@ -9,7 +9,7 @@
     "description": "Real-time gameplay infrastructure - WebSocket communication, game lifecycle management, reconnection handling, and turn timeout system",
     "totalEstimatedHours": 45,
     "totalTasks": 18,
-    "completedTasks": 8,
+    "completedTasks": 9,
     "status": "in_progress",
     "masterPlan": "../PROJECT_PLAN_MASTER.json"
   },
@@ -274,8 +274,8 @@
       "description": "Handle players joining/rejoining games",
       "category": "services",
       "priority": 8,
-      "completed": false,
-      "tested": false,
+      "completed": true,
+      "tested": true,
       "dependencies": ["GS-002"],
       "files": [
         {"path": "app/services/game_service.py", "status": "modify"}

backend/tests/unit/services/test_game_service.py

@@ -328,7 +328,7 @@ class TestJoinGame:
         """Test joining an ended game still succeeds but indicates game over.
 
         Players should be able to rejoin ended games to see the final
-        state, but is_your_turn should be False.
+        state, but is_your_turn should be False and game_over should be True.
         """
         sample_game_state.winner_id = "player-1"
         sample_game_state.end_reason = GameEndReason.PRIZES_TAKEN
@@ -338,8 +338,89 @@ class TestJoinGame:
 
         assert result.success is True
         assert result.is_your_turn is False
+        assert result.game_over is True
         assert "ended" in result.message.lower()
 
+    @pytest.mark.asyncio
+    async def test_join_game_includes_pending_forced_action(
+        self,
+        game_service: GameService,
+        mock_state_manager: AsyncMock,
+        sample_game_state: GameState,
+    ) -> None:
+        """Test that join_game includes pending forced action in result.
+
+        When a player rejoins mid-game and there's a pending forced action
+        (e.g., select new active after KO), the result should include that
+        information so the client knows what action is required.
+        """
+        # Add forced action to the game state
+        sample_game_state.forced_actions = [
+            ForcedAction(
+                player_id="player-1",
+                action_type="select_active",
+                reason="Your active Pokemon was knocked out. Select a new active.",
+                params={"available_bench_ids": ["bench-1", "bench-2"]},
+            )
+        ]
+        mock_state_manager.load_state.return_value = sample_game_state
+
+        result = await game_service.join_game("game-123", "player-1")
+
+        assert result.success is True
+        assert result.pending_forced_action is not None
+        assert result.pending_forced_action.player_id == "player-1"
+        assert result.pending_forced_action.action_type == "select_active"
+
+    @pytest.mark.asyncio
+    async def test_join_game_forced_action_sets_is_your_turn(
+        self,
+        game_service: GameService,
+        mock_state_manager: AsyncMock,
+        sample_game_state: GameState,
+    ) -> None:
+        """Test that is_your_turn is True when player has forced action.
+
+        Even if it's technically the opponent's turn, if this player has
+        a forced action pending, is_your_turn should be True so they know
+        they must act.
+        """
+        # Set current player to player-2, but forced action is for player-1
+        sample_game_state.current_player_id = "player-2"
+        sample_game_state.forced_actions = [
+            ForcedAction(
+                player_id="player-1",
+                action_type="select_active",
+                reason="Your active Pokemon was knocked out.",
+            )
+        ]
+        mock_state_manager.load_state.return_value = sample_game_state
+
+        result = await game_service.join_game("game-123", "player-1")
+
+        assert result.success is True
+        # Player-1 has forced action, so it's their turn to act
+        assert result.is_your_turn is True
+        assert result.pending_forced_action is not None
+
+    @pytest.mark.asyncio
+    async def test_join_game_active_game_not_over(
+        self,
+        game_service: GameService,
+        mock_state_manager: AsyncMock,
+        sample_game_state: GameState,
+    ) -> None:
+        """Test that game_over is False for active games.
+
+        When joining an ongoing game, game_over should be False.
+        """
+        mock_state_manager.load_state.return_value = sample_game_state
+
+        result = await game_service.join_game("game-123", "player-1")
+
+        assert result.success is True
+        assert result.game_over is False
+
 
 class TestExecuteAction:
     """Tests for the execute_action method.