import asyncio
from app.websocket import manager

async def main():
    msg = {
        "type": "read_marker",
        "user_id": 42,
        "channel_id": 4,
        "last_seen": "2025-12-12T13:30:00Z",
    }
    # Broadcast to channel and presence (0)
    await manager.broadcast_to_channel(msg, 4)
    await manager.broadcast_to_channel({**msg, "type": "read_marker"}, 0)
    print('Simulated broadcast sent:', msg)

if __name__ == '__main__':
    asyncio.run(main())