"""Queue routing — the long one-shot maintenance tasks run on a dedicated
`maintenance_long` lane so a 30-min backup or a multi-chunk audit can't starve
the quick recovery sweeps / vacuum on the concurrency-1 `maintenance` lane
(operator-flagged 2026-06-07)."""
import pytest

from backend.app.celery_app import celery


def test_long_one_shots_route_to_maintenance_long():
    routes = celery.conf.task_routes
    for prefix in (
        "backend.app.tasks.backup.*",
        "backend.app.tasks.admin.*",
        "backend.app.tasks.library_audit.*",
    ):
        assert routes[prefix]["queue"] == "maintenance_long"


def test_quick_maintenance_stays_on_maintenance():
    routes = celery.conf.task_routes
    assert routes["backend.app.tasks.maintenance.*"]["queue"] == "maintenance"


@pytest.mark.parametrize(("name", "queue"), [
    ("backend.app.tasks.external.fetch_external_link", "download"),
    # The rows #4432 found recorded on the wrong lane:
    ("backend.app.tasks.translation.translate_posts", "maintenance_long"),
    ("backend.app.tasks.gpu_queue.enqueue_gpu_backfill", "maintenance"),
    ("backend.app.tasks.maintenance.backfill_phash", "maintenance_long"),
    ("backend.app.tasks.maintenance.date_posts_from_records", "maintenance_long"),
    ("backend.app.tasks.admin.normalize_tags_task", "maintenance_long"),
    ("backend.app.tasks.backup.backup_db_task", "maintenance_long"),
    ("backend.app.tasks.maintenance.vacuum_analyze", "maintenance"),
    ("backend.app.tasks.not_routed.anything", "default"),
])
def test_task_run_records_the_queue_the_router_sends_to(name, queue):
    """TaskRun.queue comes from the router, not a copy of task_routes (#4432):
    the stall sweep's per-queue thresholds and the System activity filters both
    key off it."""
    from backend.app.celery_signals import _queue_for

    class _T:
        pass

    t = _T()
    t.name = name
    t.app = celery
    assert _queue_for(t) == queue


def test_no_task_outlives_its_stall_threshold():
    """A task whose hard time limit is longer than the stall sweep's threshold
    for it gets failed 'RecoverySweep' while it is still healthy — the class
    #4432 found on the ml, import and long-maintenance lanes. The threshold is
    resolved the way recover_stalled_task_runs resolves it: task-name override,
    then queue, then the default."""
    from backend.app.celery_signals import _queue_for
    from backend.app.tasks.maintenance import (
        QUEUE_STUCK_THRESHOLD_MINUTES,
        STUCK_THRESHOLD_MINUTES,
        TASK_STUCK_THRESHOLD_MINUTES,
    )

    celery.loader.import_default_modules()
    checked = 0
    too_short = []
    for name, task in sorted(celery.tasks.items()):
        if name.startswith("celery."):
            continue
        limit = getattr(task, "time_limit", None)
        if not limit:
            continue
        threshold = TASK_STUCK_THRESHOLD_MINUTES.get(
            name,
            QUEUE_STUCK_THRESHOLD_MINUTES.get(_queue_for(task), STUCK_THRESHOLD_MINUTES),
        )
        checked += 1
        if limit / 60 > threshold:
            too_short.append(f"{name}: limit {limit / 60:.0f} min > sweep {threshold} min")
    assert checked > 20, "the task registry did not load — this guard checked nothing"
    assert not too_short, "\n".join(too_short)


def test_backfill_phash_runs_on_the_long_lane():
    """It lives in maintenance.py, so the quick-lane glob matches it too —
    the router must pick the exact name. A 35-minute rehash on the scheduler
    lane blocked the minute ticks behind it (2026-09-24)."""
    route = celery.amqp.router.route(
        {}, "backend.app.tasks.maintenance.backfill_phash",
    )
    assert route["queue"].name == "maintenance_long"
    quick = celery.amqp.router.route(
        {}, "backend.app.tasks.maintenance.recover_stalled_task_runs",
    )
    assert quick["queue"].name == "maintenance"