Add user ping system and room deletion functionality

Backend changes:
- Fix track deletion foreign key constraint (tracks.py)
  * Clear current_track_id from rooms before deleting track
  * Prevent deletion errors when track is currently playing

- Implement user ping/keepalive system (sync.py, websocket.py, ping_task.py, main.py)
  * Track last pong timestamp for each user
  * Background task sends ping every 30s, disconnects users after 60s timeout
  * Auto-pause playback when room becomes empty
  * Remove disconnected users from room_participants

- Enhance room deletion (rooms.py)
  * Broadcast room_deleted event to all connected users
  * Close all WebSocket connections before deletion
  * Cascade delete participants, queue, and messages

Frontend changes:
- Add ping/pong WebSocket handling (activeRoom.js)
  * Auto-respond to server pings
  * Handle room_deleted event with redirect to home

- Add room deletion UI (RoomView.vue, HomeView.vue, RoomCard.vue)
  * Delete button visible only to room owner
  * Confirmation dialog with warning
  * Delete button on room cards (shows on hover)
  * Redirect to home page after deletion

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

backend/app/services/ping_task.py

@@ -0,0 +1,88 @@
+import asyncio
+import time
+from uuid import UUID
+from datetime import datetime
+from sqlalchemy import select, delete
+from app.database import async_session
+from app.models.room import Room, RoomParticipant
+from app.services.sync import manager
+
+
+async def ping_users_task():
+    """Фоновая задача для периодического пинга пользователей и отключения неактивных"""
+    while True:
+        try:
+            await asyncio.sleep(manager.ping_interval)
+
+            current_time = time.time()
+            disconnected_users = []
+
+            # Проходим по всем активным соединениям
+            for room_id, connections in list(manager.get_all_connections().items()):
+                for websocket, user_id in list(connections):
+                    # Отправляем ping
+                    try:
+                        await websocket.send_json({"type": "ping"})
+                    except Exception:
+                        # Если не смогли отправить - помечаем на отключение
+                        disconnected_users.append((websocket, room_id, user_id))
+                        continue
+
+                    # Проверяем время последнего pong
+                    last_pong_time = manager.last_pong.get((room_id, user_id))
+                    if last_pong_time is None or (current_time - last_pong_time) > manager.ping_timeout:
+                        # Пользователь не отвечает слишком долго
+                        disconnected_users.append((websocket, room_id, user_id))
+
+            # Отключаем неактивных пользователей
+            for websocket, room_id, user_id in disconnected_users:
+                await disconnect_inactive_user(websocket, room_id, user_id)
+
+        except Exception as e:
+            print(f"Error in ping_users_task: {e}")
+            await asyncio.sleep(5)  # Подождём немного при ошибке
+
+
+async def disconnect_inactive_user(websocket, room_id: UUID, user_id: UUID):
+    """Отключить неактивного пользователя"""
+    try:
+        # Закрываем WebSocket соединение
+        await websocket.close(code=1000, reason="Ping timeout")
+    except Exception:
+        pass
+
+    # Удаляем из менеджера соединений
+    manager.disconnect(websocket, room_id, user_id)
+
+    # Удаляем из БД
+    async with async_session() as db:
+        await db.execute(
+            delete(RoomParticipant).where(
+                RoomParticipant.room_id == room_id,
+                RoomParticipant.user_id == user_id
+            )
+        )
+        await db.commit()
+
+        # Проверяем, остались ли участники
+        room_user_count = manager.get_room_user_count(room_id)
+
+        # Если комната пустая - ставим трек на паузу
+        if room_user_count == 0:
+            result = await db.execute(select(Room).where(Room.id == room_id))
+            room = result.scalar_one_or_none()
+            if room and room.is_playing:
+                # Сохраняем текущую позицию
+                if room.playback_started_at:
+                    elapsed = (datetime.utcnow() - room.playback_started_at).total_seconds() * 1000
+                    room.playback_position = int((room.playback_position or 0) + elapsed)
+
+                room.is_playing = False
+                room.playback_started_at = None
+                await db.commit()
+
+    # Уведомляем остальных участников
+    await manager.broadcast_to_room(
+        room_id,
+        {"type": "user_left", "user_id": str(user_id), "reason": "timeout"},
+    )

backend/app/services/sync.py

@@ -2,24 +2,39 @@ from typing import Dict, Set
 from fastapi import WebSocket
 from uuid import UUID
 import json
+import time
+import asyncio
 
 
 class ConnectionManager:
     def __init__(self):
         # room_id -> set of (websocket, user_id)
         self.active_connections: Dict[UUID, Set[tuple[WebSocket, UUID]]] = {}
+        # (room_id, user_id) -> last pong timestamp
+        self.last_pong: Dict[tuple[UUID, UUID], float] = {}
+        # Ping interval and timeout in seconds
+        self.ping_interval = 30  # Отправлять ping каждые 30 секунд
+        self.ping_timeout = 60   # Отключать если нет ответа 60 секунд
 
     async def connect(self, websocket: WebSocket, room_id: UUID, user_id: UUID):
         await websocket.accept()
         if room_id not in self.active_connections:
             self.active_connections[room_id] = set()
         self.active_connections[room_id].add((websocket, user_id))
+        # Инициализируем время последнего pong
+        self.last_pong[(room_id, user_id)] = time.time()
 
     def disconnect(self, websocket: WebSocket, room_id: UUID, user_id: UUID):
         if room_id in self.active_connections:
             self.active_connections[room_id].discard((websocket, user_id))
             if not self.active_connections[room_id]:
                 del self.active_connections[room_id]
+        # Удаляем запись о последнем pong
+        self.last_pong.pop((room_id, user_id), None)
+
+    def update_pong(self, room_id: UUID, user_id: UUID):
+        """Обновить время последнего pong от пользователя"""
+        self.last_pong[(room_id, user_id)] = time.time()
 
     async def broadcast_to_room(self, room_id: UUID, message: dict, exclude_user: UUID = None):
         if room_id not in self.active_connections:
@@ -39,10 +54,35 @@ class ConnectionManager:
         for conn in disconnected:
             self.active_connections[room_id].discard(conn)
 
+    async def send_to_user(self, room_id: UUID, user_id: UUID, message: dict):
+        """Отправить сообщение конкретному пользователю в комнате"""
+        if room_id not in self.active_connections:
+            return False
+
+        message_json = json.dumps(message, default=str)
+        for websocket, uid in self.active_connections[room_id]:
+            if uid == user_id:
+                try:
+                    await websocket.send_text(message_json)
+                    return True
+                except Exception:
+                    return False
+        return False
+
     def get_room_user_count(self, room_id: UUID) -> int:
         if room_id not in self.active_connections:
             return 0
         return len(self.active_connections[room_id])
 
+    def get_room_users(self, room_id: UUID) -> Set[UUID]:
+        """Получить список user_id в комнате"""
+        if room_id not in self.active_connections:
+            return set()
+        return {user_id for _, user_id in self.active_connections[room_id]}
+
+    def get_all_connections(self) -> Dict[UUID, Set[tuple[WebSocket, UUID]]]:
+        """Получить все активные соединения (для фоновой задачи пинга)"""
+        return self.active_connections
+
 
 manager = ConnectionManager()