import json
import queue
import uuid
from typing import Dict, Any
import logging

from flask import Response

from events.types.event import Event

logger = logging.getLogger(__name__)

# Maps user_id → dict of {connection_id: queue}
user_queues: Dict[str, Dict[str, queue.Queue]] = {}
logging.basicConfig(level=logging.INFO)


def get_queue(user_id: str, connection_id: str) -> queue.Queue:
    """Get or create a queue for a specific user connection."""
    if user_id not in user_queues:
        user_queues[user_id] = {}

    if connection_id not in user_queues[user_id]:
        user_queues[user_id][connection_id] = queue.Queue()

    return user_queues[user_id][connection_id]


def send_to_user(user_id: str, data: Dict[str, Any]):
    """Send data to all connections for a specific user."""
    logger.info(f"Sending data to {user_id} user quesues are {user_queues.keys()}")
    if user_id in user_queues:
        logger.info(f"Queued {user_id}")
        # Format as SSE message once
        message = f"data: {json.dumps(data)}\n\n".encode('utf-8')

        # Send to all connections for this user
        for connection_id, q in user_queues[user_id].items():
            try:
                logger.info(f"Sending message to {connection_id}")
                q.put(message)
                q.put(message, block=False)
            except queue.Full:
                # Skip if queue is full (connection might be dead)
                pass


def send_event_to_user(user_id: str, event: Event):
    """Send an Event to all connections for a specific user."""
    send_to_user(user_id, event.to_dict())


def sse_response_for_user(user_id: str):
    """Create SSE response for a user connection."""
    # Generate unique connection ID
    connection_id = str(uuid.uuid4())
    user_queue = get_queue(user_id, connection_id)
    logger.info(f"SSE response for {user_id} user is {user_queues.keys()}")

    def generate():
        try:
            while True:
                # Get message from queue (blocks until available)
                logger.info(f"blocking on get for {user_id} user")
                message = user_queue.get()
                yield message
        except GeneratorExit:
            # Clean up when client disconnects
            if user_id in user_queues and connection_id in user_queues[user_id]:
                del user_queues[user_id][connection_id]

                # Remove user entry if no connections remain
                if not user_queues[user_id]:
                    del user_queues[user_id]

    return Response(
        generate(),
        mimetype='text/event-stream',
        headers={
            'Cache-Control': 'no-cache',
            'X-Accel-Buffering': 'no',
            'Connection': 'keep-alive'
        }
    )