"""
Simple in-process pub/sub for server-sent events.

Usage:
    # Publisher (e.g. nextcloud_talk router)
    await event_bus.publish({"type": "nct_message", ...})

    # Consumer (SSE endpoint in chat router)
    q = event_bus.subscribe()
    try:
        event = await asyncio.wait_for(q.get(), timeout=20)
    finally:
        event_bus.unsubscribe(q)
"""
import asyncio
from typing import Any

_subscribers: set[asyncio.Queue] = set()


def subscribe() -> asyncio.Queue:
    q: asyncio.Queue = asyncio.Queue()
    _subscribers.add(q)
    return q


def unsubscribe(q: asyncio.Queue) -> None:
    _subscribers.discard(q)


async def publish(event: dict[str, Any]) -> None:
    for q in list(_subscribers):
        await q.put(event)