"""Loop-lag watchdog: what the deep health check reads."""

from fastapi.testclient import TestClient

from fluksio.flow.events import EventBus
from fluksio.flow.watchdog import DEGRADED_STRIKES, LoopWatchdog
from fluksio.main import app


def test_a_responsive_loop_stays_healthy():
    watchdog = LoopWatchdog()

    for _ in range(10):
        watchdog._record(0.002)

    assert not watchdog.degraded
    assert watchdog.snapshot()["max_60s"] == 2.0


def test_sustained_lag_marks_the_engine_degraded():
    watchdog = LoopWatchdog()

    for _ in range(20):
        watchdog._record(1.0)

    assert watchdog.degraded


def test_a_blocked_loop_is_announced_once_it_keeps_happening():
    events = []
    bus = EventBus()
    bus.publish = events.append  # type: ignore[method-assign]
    watchdog = LoopWatchdog(bus)

    for _ in range(DEGRADED_STRIKES - 1):
        watchdog._record(6.0)
    assert events == []

    watchdog._record(6.0)
    assert [e["type"] for e in events] == ["engine_degraded"]

    # A recovered loop resets the count, so the next stall is announced again.
    watchdog._record(0.001)
    for _ in range(DEGRADED_STRIKES):
        watchdog._record(6.0)
    assert len(events) == 2


def test_health_reports_503_once_the_loop_is_wedged():
    """The point of the deep check: unhealthy without the process being dead."""
    watchdog = LoopWatchdog()
    app.state.watchdog = watchdog
    # No lifespan here, so there is no controller either — the endpoint has to
    # cope with a half-built app rather than assume the engine is up.
    client = TestClient(app)
    try:
        assert client.get("/api/v1/utils/health/").status_code == 200

        for _ in range(20):
            watchdog._record(1.0)

        response = client.get("/api/v1/utils/health/")
        assert response.status_code == 503
        body = response.json()
        assert body["status"] == "degraded"
        assert body["problems"] == ["event loop lagging"]
    finally:
        del app.state.watchdog