"""Real-time communication routes using WebRTC."""
from fastapi import APIRouter, WebSocket, WebSocketDisconnect, Depends
from typing import Dict, Set
import json
import logging
from datetime import datetime

from core.security import get_current_user

router = APIRouter(prefix="/realtime", tags=["Real-time"])
logger = logging.getLogger(__name__)

# Store active WebSocket connections
active_connections: Set[WebSocket] = set()


@router.websocket("/ws")
async def websocket_endpoint(websocket: WebSocket):
    """
    WebSocket endpoint for real-time bidirectional communication.
    
    This endpoint provides a WebSocket connection for:
    - WebRTC signaling (offer/answer/ICE candidates)
    - Real-time text messages
    - JSON data exchange
    
    **Message Format:**
    ```json
    {
        "type": "offer|answer|ice_candidate|message|data",
        "payload": {...}
    }
    ```
    
    **Authentication:**
    For production, you should authenticate the WebSocket connection.
    You can pass the JWT token as a query parameter: ws://host/realtime/ws?token=<jwt>
    """
    await websocket.accept()
    active_connections.add(websocket)
    
    connection_id = id(websocket)
    logger.info(f"WebSocket connection established: {connection_id}")
    
    try:
        # Send welcome message
        await websocket.send_json({
            "type": "connected",
            "payload": {
                "connection_id": connection_id,
                "timestamp": datetime.utcnow().isoformat(),
                "message": "WebSocket connection established"
            }
        })
        
        # Listen for messages
        while True:
            # Receive message
            message = await websocket.receive_text()
            
            try:
                data = json.loads(message)
                message_type = data.get("type", "unknown")
                payload = data.get("payload", {})
                
                logger.info(f"Received {message_type} from {connection_id}")
                
                # Handle different message types
                if message_type == "offer":
                    # WebRTC offer
                    response = await handle_webrtc_offer(payload)
                    await websocket.send_json(response)
                    
                elif message_type == "answer":
                    # WebRTC answer
                    response = await handle_webrtc_answer(payload)
                    await websocket.send_json(response)
                    
                elif message_type == "ice_candidate":
                    # ICE candidate for WebRTC
                    response = await handle_ice_candidate(payload)
                    await websocket.send_json(response)
                    
                elif message_type == "message":
                    # Text message
                    response = await handle_text_message(payload)
                    await websocket.send_json(response)
                    
                elif message_type == "ping":
                    # Ping/pong for keep-alive
                    await websocket.send_json({
                        "type": "pong",
                        "payload": {
                            "timestamp": datetime.utcnow().isoformat()
                        }
                    })
                    
                else:
                    # Unknown message type
                    await websocket.send_json({
                        "type": "error",
                        "payload": {
                            "message": f"Unknown message type: {message_type}"
                        }
                    })
                    
            except json.JSONDecodeError:
                await websocket.send_json({
                    "type": "error",
                    "payload": {
                        "message": "Invalid JSON format"
                    }
                })
                
    except WebSocketDisconnect:
        logger.info(f"WebSocket disconnected: {connection_id}")
    except Exception as e:
        logger.error(f"WebSocket error: {str(e)}", exc_info=True)
    finally:
        active_connections.discard(websocket)
        logger.info(f"WebSocket connection closed: {connection_id}")


async def handle_webrtc_offer(payload: dict) -> dict:
    """
    Handle WebRTC offer.
    
    In a full implementation, this would:
    1. Create a peer connection
    2. Set remote description (offer)
    3. Create and return an answer
    
    Args:
        payload: WebRTC offer SDP
        
    Returns:
        Response with answer or error
    """
    # Placeholder implementation
    # TODO: Implement full WebRTC signaling with aiortc
    return {
        "type": "answer",
        "payload": {
            "message": "WebRTC offer received. Full implementation pending.",
            "sdp": payload.get("sdp", ""),
            "note": "This is a placeholder. Implement with aiortc for production."
        }
    }


async def handle_webrtc_answer(payload: dict) -> dict:
    """
    Handle WebRTC answer.
    
    Args:
        payload: WebRTC answer SDP
        
    Returns:
        Acknowledgment
    """
    return {
        "type": "ack",
        "payload": {
            "message": "WebRTC answer received"
        }
    }


async def handle_ice_candidate(payload: dict) -> dict:
    """
    Handle ICE candidate.
    
    Args:
        payload: ICE candidate data
        
    Returns:
        Acknowledgment
    """
    return {
        "type": "ack",
        "payload": {
            "message": "ICE candidate received"
        }
    }


async def handle_text_message(payload: dict) -> dict:
    """
    Handle text message.
    
    This can be extended to:
    - Send to AI agent for processing
    - Broadcast to other connections
    - Store in database
    
    Args:
        payload: Message data with 'text' field
        
    Returns:
        Response message
    """
    text = payload.get("text", "")
    
    # Echo the message back (placeholder)
    # TODO: Integrate with agent service for AI responses
    return {
        "type": "message",
        "payload": {
            "text": f"Received: {text}",
            "timestamp": datetime.utcnow().isoformat(),
            "note": "This is an echo. Integrate with agent_service for AI responses."
        }
    }


@router.get("/connections")
async def get_active_connections(
    current_user: dict = Depends(get_current_user)
) -> dict:
    """
    Get count of active WebSocket connections.
    
    Args:
        current_user: Authenticated user
        
    Returns:
        Connection statistics
    """
    return {
        "active_connections": len(active_connections),
        "timestamp": datetime.utcnow().isoformat()
    }


@router.post("/broadcast")
async def broadcast_message(
    message: dict,
    current_user: dict = Depends(get_current_user)
) -> dict:
    """
    Broadcast a message to all active WebSocket connections.
    
    Args:
        message: Message to broadcast
        current_user: Authenticated user
        
    Returns:
        Broadcast status
    """
    broadcast_count = 0
    
    for connection in active_connections:
        try:
            await connection.send_json({
                "type": "broadcast",
                "payload": message
            })
            broadcast_count += 1
        except Exception as e:
            logger.error(f"Failed to broadcast to connection: {str(e)}")
    
    return {
        "message": "Broadcast sent",
        "recipients": broadcast_count,
        "timestamp": datetime.utcnow().isoformat()
    }