"""
api/state_sync.py — S901: Real-Time State Synchronizer (UltraVSS Beta Strategy)

Router FastAPI per la sincronizzazione dello stato tramite WebSocket.
"""

from fastapi import APIRouter, WebSocket, WebSocketDisconnect
from typing import List, Dict, Any
import logging

_logger = logging.getLogger("api.state_sync")
router = APIRouter(prefix="/api/sync", tags=["sync"])

class ConnectionManager:
    def __init__(self):
        self.active_connections: Dict[str, List[WebSocket]] = {}
        self.room_states: Dict[str, Any] = {}

    async def connect(self, websocket: WebSocket, room_id: str):
        await websocket.accept()
        if room_id not in self.active_connections:
            self.active_connections[room_id] = []
        self.active_connections[room_id].append(websocket)
        
        if room_id in self.room_states:
            await websocket.send_json({
                "type": "SYNC_STATE",
                "payload": self.room_states[room_id]
            })

    def disconnect(self, websocket: WebSocket, room_id: str):
        if room_id in self.active_connections:
            if websocket in self.active_connections[room_id]:
                self.active_connections[room_id].remove(websocket)
            if not self.active_connections[room_id]:
                del self.active_connections[room_id]

    async def broadcast(self, message: dict, room_id: str, exclude: WebSocket = None):
        if room_id not in self.active_connections:
            return
        
        if message.get("type") == "UPDATE_STATE":
            self.room_states[room_id] = message.get("payload")

        for connection in self.active_connections[room_id]:
            if connection != exclude:
                try:
                    await connection.send_json(message)
                except Exception as e:
                    _logger.error(f"Error broadcasting to client in room {room_id}: {e}")

manager = ConnectionManager()

@router.websocket("/ws/{room_id}")
async def websocket_endpoint(websocket: WebSocket, room_id: str):
    await manager.connect(websocket, room_id)
    try:
        while True:
            data = await websocket.receive_json()
            await manager.broadcast(data, room_id, exclude=websocket)
    except WebSocketDisconnect:
        manager.disconnect(websocket, room_id)
    except Exception as e:
        _logger.error(f"WebSocket error in room {room_id}: {e}")
        manager.disconnect(websocket, room_id)