from typing import AsyncGenerator
import strawberry
from channels.db import database_sync_to_async
from strawberry.types import Info
from core.graphql.pubsub import pubsub
from core.graphql.types.service import ServiceType
from core.graphql.utils import _extract_id
from core.models.service import Service


@strawberry.type
class Subscription:
    @strawberry.subscription(description="Subscribe to service visit creation events")
    async def service_created(self, info: Info) -> AsyncGenerator[ServiceType, None]:
        user = info.context.user
        if not user or not user.is_authenticated:
            raise PermissionError("Authentication required")

        async with pubsub.subscribe("service_created") as subscriber:
            async for payload in subscriber:
                service_id = await _extract_id(payload)
                try:
                    instance = await database_sync_to_async(Service.objects.get)(pk=service_id)
                except Service.DoesNotExist:
                    continue
                yield instance

    @strawberry.subscription(description="Subscribe to service visit updates")
    async def service_updated(self, info: Info) -> AsyncGenerator[ServiceType, None]:
        user = info.context.user
        if not user or not user.is_authenticated:
            raise PermissionError("Authentication required")

        async with pubsub.subscribe("service_updated") as subscriber:
            async for payload in subscriber:
                service_id = await _extract_id(payload)
                try:
                    instance = await database_sync_to_async(Service.objects.get)(pk=service_id)
                except Service.DoesNotExist:
                    continue
                yield instance

    @strawberry.subscription(description="Subscribe to service visit deletion events")
    async def service_deleted(self, info: Info) -> AsyncGenerator[strawberry.ID, None]:
        user = info.context.user
        if not user or not user.is_authenticated:
            raise PermissionError("Authentication required")

        async with pubsub.subscribe("service_deleted") as subscriber:
            async for payload in subscriber:
                service_id = await _extract_id(payload)
                yield strawberry.ID(service_id)