# import json
# from django.contrib.auth.models import AnonymousUser
# from django.contrib.auth import get_user_model
# from django.db import close_old_connections
# from urllib.parse import parse_qs
# from channels.db import database_sync_to_async
# from inventory.models import Notification
# import asyncio

# @database_sync_to_async
# def get_notifications(user, last_id):
#     return Notification.objects.filter(
#         user=user, id__gt=last_id, is_read=False
#     ).order_by("created")

# class NotificationSSEApp:
#     async def __call__(self, scope, receive, send):
#         if scope["type"] != "http":
#             return

#         query_string = parse_qs(scope["query_string"].decode())
#         last_id = int(query_string.get("last_id", [0])[0])

#         # Get user from scope if using AuthMiddlewareStack
#         user = scope.get("user", AnonymousUser())
#         if not user.is_authenticated:
#             await send({
#                 "type": "http.response.start",
#                 "status": 403,
#                 "headers": [(b"content-type", b"text/plain")],
#             })
#             await send({
#                 "type": "http.response.body",
#                 "body": b"Unauthorized",
#             })
#             return

#         await send({
#             "type": "http.response.start",
#             "status": 200,
#             "headers": [
#                 (b"content-type", b"text/event-stream"),
#                 (b"cache-control", b"no-cache"),
#                 (b"x-accel-buffering", b"no"),
#             ]
#         })

#         try:
#             while True:
#                 close_old_connections()

#                 notifications = await get_notifications(user, last_id)
#                 for notification in notifications:
#                     data = {
#                         "id": notification.id,
#                         "message": notification.message,
#                         "created": notification.created.isoformat(),
#                         "is_read": notification.is_read,
#                     }

#                     event_str = (
#                         f"id: {notification.id}\n"
#                         f"event: notification\n"
#                         f"data: {json.dumps(data)}\n\n"
#                     )

#                     await send({
#                         "type": "http.response.body",
#                         "body": event_str.encode("utf-8"),
#                         "more_body": True
#                     })

#                     last_id = notification.id

#                 await asyncio.sleep(2)

#         except asyncio.CancelledError:
#             pass

import json
import time
from django.contrib.auth.models import AnonymousUser
from urllib.parse import parse_qs
from channels.db import database_sync_to_async
from django.contrib.auth import get_user_model
from inventory.models import Notification
import asyncio
from datetime import datetime

@database_sync_to_async
def get_user(user_id):
    User = get_user_model()
    try:
        return User.objects.get(id=user_id)
    except User.DoesNotExist:
        return AnonymousUser()

@database_sync_to_async
def get_notifications(user, last_id):
    notifications = Notification.objects.filter(
        user=user,
        id__gt=last_id,
        is_read=False
    ).order_by("created")

    return [
        {
            'id': n.id,
            'message': n.message,
            'created': n.created.isoformat(),  # Convert datetime to string
            'is_read': n.is_read
        }
        for n in notifications
    ]

class NotificationSSEApp:
    async def __call__(self, scope, receive, send):
        if scope["type"] != "http":
            return

        # Parse query parameters
        query_string = parse_qs(scope["query_string"].decode())
        last_id = int(query_string.get("last_id", [0])[0])

        # Get user from scope
        user = scope.get("user")
        if not user or user.is_anonymous:
            await self._send_response(send, 403, b"Unauthorized")
            return

        # Send SSE headers
        await self._send_headers(send)

        try:
            while True:
                try:
                    message = await asyncio.wait_for(receive(), timeout=3)
                    if message["type"] == "http.disconnect":
                        print("🔌 Client disconnected")
                        break
                except asyncio.TimeoutError:
                    notifications = await get_notifications(user, last_id)

                    for notification in notifications:
                        await self._send_notification(send, notification)
                        if notification['id'] > last_id:
                            last_id = notification['id']

                    # Send keep-alive comment every 15 seconds
                    await send({
                        "type": "http.response.body",
                        "body": b":keep-alive\n\n",
                        "more_body": True
                    })

                # await asyncio.sleep(3)

        except (asyncio.CancelledError, ConnectionResetError):
            pass
        finally:
            await self._close_connection(send)

    async def _send_headers(self, send):
        await send({
            "type": "http.response.start",
            "status": 200,
            "headers": [
                (b"content-type", b"text/event-stream"),
                (b"cache-control", b"no-cache"),
                (b"connection", b"keep-alive"),
                (b"x-accel-buffering", b"no"),
            ]
        })

    async def _send_notification(self, send, notification):
        try:
            event_str = (
                f"id: {notification['id']}\n"
                f"event: notification\n"
                f"data: {json.dumps(notification)}\n\n"
            )
            await send({
                "type": "http.response.body",
                "body": event_str.encode("utf-8"),
                "more_body": True
            })
        except Exception as e:
            print(f"Error sending notification: {e}")

    async def _send_response(self, send, status, body):
        await send({
            "type": "http.response.start",
            "status": status,
            "headers": [(b"content-type", b"text/plain")]
        })
        await send({
            "type": "http.response.body",
            "body": body
        })

    async def _close_connection(self, send):
        await send({
            "type": "http.response.body",
            "body": b""
        })