Added missing methods and implemented tests

lib/data/dao/game_dao.dart

@@ -57,13 +57,21 @@ class GameDao extends DatabaseAccessor<AppDatabase> with _$GameDaoMixin {
         GameTableCompanion.insert(
           id: game.id,
           name: game.name,
-          winnerId: Value(game.winner),
+          winnerId: game.winner,
         ),
         mode: InsertMode.insertOrReplace,
       );
     });
   }
 
+  /// Deletes the game with the given [gameId] from the database.
+  /// Returns `true` if more than 0 rows were affected, otherwise `false`.
+  Future<bool> deleteGame({required String gameId}) async {
+    final query = delete(gameTable)..where((g) => g.id.equals(gameId));
+    final rowsAffected = await query.go();
+    return rowsAffected > 0;
+  }
+
   /// Retrieves the number of games in the database.
   Future<int> getGameCount() async {
     final count =
@@ -72,4 +80,12 @@ class GameDao extends DatabaseAccessor<AppDatabase> with _$GameDaoMixin {
             .getSingle();
     return count ?? 0;
   }
+
+  /// Checks if a game with the given [gameId] exists in the database.
+  /// Returns `true` if the game exists, otherwise `false`.
+  Future<bool> gameExists({required String gameId}) async {
+    final query = select(gameTable)..where((g) => g.id.equals(gameId));
+    final result = await query.getSingleOrNull();
+    return result != null;
+  }
 }

lib/data/dao/game_dao.g.dart

@@ -4,5 +4,6 @@ part of 'game_dao.dart';
 
 // ignore_for_file: type=lint
 mixin _$GameDaoMixin on DatabaseAccessor<AppDatabase> {
+  $PlayerTableTable get playerTable => attachedDatabase.playerTable;
   $GameTableTable get gameTable => attachedDatabase.gameTable;
 }

lib/data/dao/group_dao.dart

@@ -51,6 +51,9 @@ class GroupDao extends DatabaseAccessor<AppDatabase> with _$GroupDaoMixin {
               .toList(),
         ),
       );
+      await Future.wait(
+        group.members.map((player) => db.playerDao.addPlayer(player: player)),
+      );
     });
   }
 
@@ -65,11 +68,11 @@ class GroupDao extends DatabaseAccessor<AppDatabase> with _$GroupDaoMixin {
   /// Updates the name of the group with the given [id] to [newName].
   /// Returns `true` if more than 0 rows were affected, otherwise `false`.
   Future<bool> updateGroupname({
-    required String id,
+    required String groupId,
     required String newName,
   }) async {
     final rowsAffected =
-        await (update(groupTable)..where((g) => g.id.equals(id))).write(
+        await (update(groupTable)..where((g) => g.id.equals(groupId))).write(
           GroupTableCompanion(name: Value(newName)),
         );
     return rowsAffected > 0;
@@ -83,4 +86,12 @@ class GroupDao extends DatabaseAccessor<AppDatabase> with _$GroupDaoMixin {
             .getSingle();
     return count ?? 0;
   }
+
+  /// Checks if a group with the given [groupId] exists in the database.
+  /// Returns `true` if the group exists, `false` otherwise.
+  Future<bool> groupExists({required String groupId}) async {
+    final query = select(groupTable)..where((g) => g.id.equals(groupId));
+    final result = await query.getSingleOrNull();
+    return result != null;
+  }
 }

lib/data/dao/player_game_dao.g.dart

@@ -5,6 +5,6 @@ part of 'player_game_dao.dart';
 // ignore_for_file: type=lint
 mixin _$PlayerGameDaoMixin on DatabaseAccessor<AppDatabase> {
   $PlayerTableTable get playerTable => attachedDatabase.playerTable;
-  $GroupTableTable get groupTable => attachedDatabase.groupTable;
+  $GameTableTable get gameTable => attachedDatabase.gameTable;
   $PlayerGameTableTable get playerGameTable => attachedDatabase.playerGameTable;
 }

lib/data/dao/player_group_dao.dart

@@ -16,7 +16,7 @@ class PlayerGroupDao extends DatabaseAccessor<AppDatabase>
       ..where((pG) => pG.groupId.equals(groupId));
     final result = await query.get();
 
-    List<Player> groupMembers = [];
+    List<Player> groupMembers = List.empty(growable: true);
 
     for (var entry in result) {
       final player = await db.playerDao.getPlayerById(playerId: entry.playerId);
@@ -38,13 +38,38 @@ class PlayerGroupDao extends DatabaseAccessor<AppDatabase>
     return rowsAffected > 0;
   }
 
-  /// Adds a player to a group with the given [playerId] and [groupId].
-  Future<void> addPlayerToGroup({
+  /// Adds a [player] to a group with the given [groupId].
+  /// If the player is already in the group, no action is taken.
+  /// If the player does not exist in the player table, they are added.
+  /// Returns `true` if the player was added, otherwise `false`.
+  Future<bool> addPlayerToGroup({
+    required Player player,
+    required String groupId,
+  }) async {
+    if (await isPlayerInGroup(playerId: player.id, groupId: groupId)) {
+      return false;
+    }
+
+    if (await db.playerDao.playerExists(playerId: player.id) == false) {
+      db.playerDao.addPlayer(player: player);
+    }
+
+    await into(playerGroupTable).insert(
+      PlayerGroupTableCompanion.insert(playerId: player.id, groupId: groupId),
+    );
+
+    return true;
+  }
+
+  /// Checks if a player with [playerId] is in the group with [groupId].
+  /// Returns `true` if the player is in the group, otherwise `false`.
+  Future<bool> isPlayerInGroup({
     required String playerId,
     required String groupId,
   }) async {
-    await into(playerGroupTable).insert(
-      PlayerGroupTableCompanion.insert(playerId: playerId, groupId: groupId),
-    );
+    final query = select(playerGroupTable)
+      ..where((p) => p.playerId.equals(playerId) & p.groupId.equals(groupId));
+    final result = await query.getSingleOrNull();
+    return result != null;
   }
 }