import asyncio
from types import SimpleNamespace
from unittest.mock import AsyncMock
from uuid import uuid4

import pytest

from app.infra.db.postgresql.workbench_event_hub import WorkbenchEventHub, WorkbenchEventHubManager
from app.infra.db.postgresql import workbench_event_hub as hub_module


@pytest.fixture
def anyio_backend():
    return "asyncio"


@pytest.mark.anyio
async def test_project_subscribers_share_one_hub_and_idle_close(monkeypatch):
    start = AsyncMock()
    close = AsyncMock()
    monkeypatch.setattr(WorkbenchEventHub, "start", start)
    monkeypatch.setattr(WorkbenchEventHub, "close", close)
    manager = WorkbenchEventHubManager(idle_seconds=0.01)
    project_id = uuid4()

    async with manager.subscribe(project_id, "postgresql://test/db") as first:
        async with manager.subscribe(project_id, "postgresql://test/db") as second:
            assert first is second
            assert first.subscribers == 2
        assert first.subscribers == 1

    await asyncio.sleep(0.03)
    assert len(manager._hubs) == 0
    close.assert_awaited_once()


@pytest.mark.anyio
async def test_idle_subscribers_share_cursor_reads_and_notification_invalidates_the_cache(monkeypatch):
    reads = 0

    class Repository:
        def __init__(self, *_args):
            pass

        async def read_after(self, _after):
            nonlocal reads
            reads += 1
            return []

    monkeypatch.setattr(hub_module, "WorkbenchEventRepository", Repository)
    hub = WorkbenchEventHub(uuid4(), "postgresql://test/db")
    hub._connection = SimpleNamespace(closed=False)
    monkeypatch.setattr(hub, "start", AsyncMock())
    await asyncio.gather(*(hub.read_after(0) for _ in range(20)))
    assert reads == 1
    await hub._wake()
    await asyncio.gather(*(hub.read_after(0) for _ in range(20)))
    assert reads == 2


@pytest.mark.anyio
async def test_notification_during_read_does_not_cache_stale_results(monkeypatch):
    entered, release = asyncio.Event(), asyncio.Event()
    reads = 0

    class Repository:
        def __init__(self, *_args):
            pass

        async def read_after(self, _after):
            nonlocal reads
            reads += 1
            if reads == 1:
                entered.set()
                await release.wait()
            return []

    monkeypatch.setattr(hub_module, "WorkbenchEventRepository", Repository)
    hub = WorkbenchEventHub(uuid4(), "postgresql://test/db")
    hub._connection = SimpleNamespace(closed=False)
    monkeypatch.setattr(hub, "start", AsyncMock())
    first = asyncio.create_task(hub.read_after(0))
    await entered.wait()
    await hub._wake()
    release.set()
    await first
    await hub.read_after(0)
    assert reads == 2
    for cursor in range(100):
        await hub.read_after(cursor)
    assert len(hub._reads) == 32