"""ProgressBus pubsub semantics."""
import asyncio

import pytest

from backend.app.services.progress import ProgressBus, ProgressEvent


@pytest.mark.asyncio
async def test_subscribe_replays_history():
    bus = ProgressBus()
    bus.publish(ProgressEvent(video_id="v1", stage="scenes", message="hello"))
    bus.publish(ProgressEvent(video_id="v1", stage="embed", message="world"))

    q = await bus.subscribe("v1")
    received = [q.get_nowait().stage for _ in range(2)]
    assert received == ["scenes", "embed"]


@pytest.mark.asyncio
async def test_publish_pushes_to_live_subscriber():
    bus = ProgressBus()
    q = await bus.subscribe("v1")
    bus.publish(ProgressEvent(video_id="v1", stage="done", message="ok", percent=100.0))

    ev = await asyncio.wait_for(q.get(), timeout=1.0)
    assert ev.stage == "done"
    assert ev.percent == 100.0


@pytest.mark.asyncio
async def test_unsubscribe_stops_delivery():
    bus = ProgressBus()
    q = await bus.subscribe("v1")
    await bus.unsubscribe("v1", q)
    bus.publish(ProgressEvent(video_id="v1", stage="done", message="late"))

    with pytest.raises(asyncio.QueueEmpty):
        q.get_nowait()


@pytest.mark.asyncio
async def test_subscribers_isolated_per_video():
    bus = ProgressBus()
    q_a = await bus.subscribe("v1")
    q_b = await bus.subscribe("v2")
    bus.publish(ProgressEvent(video_id="v1", stage="done", message="x"))

    assert q_a.get_nowait().video_id == "v1"
    with pytest.raises(asyncio.QueueEmpty):
        q_b.get_nowait()