"""FC-3h: backup/restore Celery task integration tests.

Uses task_always_eager for synchronous in-test execution.
Subprocess + IMAGES_ROOT are monkeypatched so tests don't touch
real /images or shell out to pg_dump.
"""
from datetime import UTC, datetime, timedelta
from pathlib import Path

import pytest
from sqlalchemy import select

from backend.app.celery_app import celery
from backend.app.models import BackupRun, ImportSettings

pytestmark = pytest.mark.integration


@pytest.fixture(autouse=True)
def _eager_celery(monkeypatch):
    monkeypatch.setattr(celery.conf, "task_always_eager", True)
    monkeypatch.setattr(celery.conf, "task_eager_propagates", False)


@pytest.fixture(autouse=True)
def fake_subprocess_and_images_root(monkeypatch, tmp_path):
    monkeypatch.setattr("backend.app.tasks.backup.IMAGES_ROOT", tmp_path)
    monkeypatch.setattr(
        "backend.app.services.backup_service._DB_SUBPROCESS_TIMEOUT_S", 5,
    )

    class _FakeProc:
        returncode = 0
        stdout = b""
        stderr = b""

    def _sentinel(cmd):
        if cmd[0] == "pg_dump":
            i = cmd.index("-f")
            Path(cmd[i + 1]).write_bytes(b"-- fake pg_dump\n")
        elif cmd[0] == "tar" and "-cf" in cmd:
            i = cmd.index("-cf")
            Path(cmd[i + 1]).write_bytes(b"fake tar payload")

    def _fake_run(cmd, **kwargs):
        _sentinel(cmd)
        return _FakeProc()

    class _FakePopen:
        def __init__(self, cmd, **kwargs):
            self.returncode = 0
            _sentinel(cmd)

        def communicate(self, timeout=None):
            return (b"", b"")

        def kill(self):
            self.returncode = -9

    # backup_db/backup_images go through _run_bounded (Popen); restore via run.
    monkeypatch.setattr("subprocess.run", _fake_run)
    monkeypatch.setattr("subprocess.Popen", _FakePopen)


def _seed_backup(db_sync, *, kind, status, started_at, tag=None,
                 finished_at=None):
    row = BackupRun(
        kind=kind, status=status, tag=tag,
        triggered_by="manual", started_at=started_at,
        finished_at=finished_at or (started_at + timedelta(seconds=10)),
        sql_path="/tmp/fake.sql" if kind == "db" else None,
        tar_path="/tmp/fake.tar.zst" if kind == "images" else None,
        manifest={},
    )
    db_sync.add(row)
    db_sync.flush()
    return row.id


# --- backup_db_task --------------------------------------------------


@pytest.mark.asyncio
async def test_backup_db_task_creates_backup_run_row_status_ok(db_sync):
    from backend.app.tasks.backup import backup_db_task
    result = backup_db_task.delay(tag=None, triggered_by="manual").get()
    run_id = result["backup_run_id"]
    row = db_sync.execute(
        select(
            BackupRun.kind, BackupRun.status, BackupRun.sql_path,
            BackupRun.size_bytes, BackupRun.finished_at, BackupRun.error,
        ).where(BackupRun.id == run_id)
    ).one()
    assert row.kind == "db"
    assert row.status == "ok"
    assert row.sql_path and row.sql_path.endswith(".dump")
    assert row.size_bytes is not None and row.size_bytes > 0
    assert row.finished_at is not None
    assert row.error is None


@pytest.mark.asyncio
async def test_backup_db_task_records_failure_on_subprocess_error(db_sync, monkeypatch):
    from backend.app.tasks.backup import backup_db_task

    def _boom(*a, **kw):
        raise RuntimeError("synthetic pg_dump fail")
    # backup_db dumps via _run_bounded → subprocess.Popen.
    monkeypatch.setattr("subprocess.Popen", _boom)

    with pytest.raises(RuntimeError):
        backup_db_task.delay().get()

    row = db_sync.execute(
        select(BackupRun.status, BackupRun.error)
        .where(BackupRun.kind == "db")
        .order_by(BackupRun.id.desc()).limit(1)
    ).one()
    assert row.status == "error"
    assert "synthetic" in (row.error or "")


@pytest.mark.asyncio
async def test_backup_db_task_persists_tag(db_sync):
    from backend.app.tasks.backup import backup_db_task
    result = backup_db_task.delay(tag="pre-cutover").get()
    tag = db_sync.execute(
        select(BackupRun.tag).where(BackupRun.id == result["backup_run_id"])
    ).scalar_one()
    assert tag == "pre-cutover"


# --- backup_images_task ---------------------------------------------


@pytest.mark.asyncio
async def test_backup_images_task_creates_backup_run(db_sync):
    from backend.app.tasks.backup import backup_images_task
    result = backup_images_task.delay().get()
    row = db_sync.execute(
        select(BackupRun.kind, BackupRun.status, BackupRun.tar_path)
        .where(BackupRun.id == result["backup_run_id"])
    ).one()
    assert row.kind == "images"
    assert row.status == "ok"
    assert row.tar_path and row.tar_path.endswith(".tar.zst")


# --- restore_db_task ------------------------------------------------


@pytest.mark.asyncio
async def test_restore_db_task_creates_restoring_marker_then_restored(db_sync):
    from backend.app.tasks.backup import backup_db_task, restore_db_task
    src = backup_db_task.delay().get()
    src_id = src["backup_run_id"]

    restore_db_task.delay(source_backup_run_id=src_id).get()

    rows = db_sync.execute(
        select(BackupRun.status, BackupRun.triggered_by)
        .where(BackupRun.restored_from_id == src_id)
    ).all()
    assert len(rows) == 1
    assert rows[0].status == "restored"
    assert rows[0].triggered_by == "restore"


@pytest.mark.asyncio
async def test_restore_db_task_rejects_non_db_source(db_sync):
    from backend.app.tasks.backup import restore_db_task

    now = datetime.now(UTC)
    img_id = _seed_backup(db_sync, kind="images", status="ok", started_at=now)
    db_sync.commit()

    with pytest.raises(ValueError):
        restore_db_task.delay(source_backup_run_id=img_id).get()


# --- prune_backups --------------------------------------------------


def test_prune_backups_keeps_last_n_untagged_per_kind(db_sync):
    from backend.app.tasks.backup import prune_backups

    s = db_sync.execute(
        select(ImportSettings).where(ImportSettings.id == 1)
    ).scalar_one()
    s.backup_db_keep_last_n = 2
    s.backup_images_keep_last_n = 1
    db_sync.commit()

    now = datetime.now(UTC)
    for i in range(4):
        _seed_backup(db_sync, kind="db", status="ok",
                     started_at=now - timedelta(hours=i))
    for i in range(3):
        _seed_backup(db_sync, kind="images", status="ok",
                     started_at=now - timedelta(hours=i))
    db_sync.commit()

    result = prune_backups.apply().get()
    assert result["db_deleted"] == 2
    assert result["images_deleted"] == 2


def test_prune_backups_protects_tagged_rows(db_sync):
    from backend.app.tasks.backup import prune_backups

    s = db_sync.execute(
        select(ImportSettings).where(ImportSettings.id == 1)
    ).scalar_one()
    s.backup_db_keep_last_n = 1
    db_sync.commit()

    now = datetime.now(UTC)
    _seed_backup(db_sync, kind="db", status="ok", started_at=now)
    tagged_id = _seed_backup(
        db_sync, kind="db", status="ok",
        started_at=now - timedelta(days=30), tag="forever",
    )
    _seed_backup(db_sync, kind="db", status="ok",
                 started_at=now - timedelta(days=1))
    db_sync.commit()

    prune_backups.apply().get()

    surviving_tag = db_sync.execute(
        select(BackupRun.tag).where(BackupRun.id == tagged_id)
    ).scalar_one_or_none()
    assert surviving_tag == "forever"


def test_prune_backups_never_deletes_running_or_restoring(db_sync):
    from backend.app.tasks.backup import prune_backups

    s = db_sync.execute(
        select(ImportSettings).where(ImportSettings.id == 1)
    ).scalar_one()
    s.backup_db_keep_last_n = 0
    db_sync.commit()

    ancient = datetime.now(UTC) - timedelta(days=30)
    running_id = _seed_backup(db_sync, kind="db", status="running", started_at=ancient)
    restoring_id = _seed_backup(db_sync, kind="db", status="restoring", started_at=ancient)
    db_sync.commit()

    prune_backups.apply().get()

    statuses = db_sync.execute(
        select(BackupRun.status).where(BackupRun.id.in_([running_id, restoring_id]))
    ).scalars().all()
    assert set(statuses) == {"running", "restoring"}


# --- recover_stalled_backup_runs (per-kind threshold, FC #739) -------


def test_stall_sweep_flips_db_fast_but_spares_running_images(db_sync):
    from backend.app.tasks.maintenance import recover_stalled_backup_runs

    now = datetime.now(UTC)
    # A db backup stuck 50 min → past the 40-min db window → flipped to error.
    db_id = _seed_backup(
        db_sync, kind="db", status="running",
        started_at=now - timedelta(minutes=50),
    )
    # An images backup running 50 min is still well under the 7h window → spared.
    img_id = _seed_backup(
        db_sync, kind="images", status="running",
        started_at=now - timedelta(minutes=50),
    )
    db_sync.commit()

    recover_stalled_backup_runs.apply().get()

    db_status = db_sync.execute(
        select(BackupRun.status).where(BackupRun.id == db_id)
    ).scalar_one()
    img_status = db_sync.execute(
        select(BackupRun.status).where(BackupRun.id == img_id)
    ).scalar_one()
    assert db_status == "error"
    assert img_status == "running"


# --- backup_db_nightly ----------------------------------------------


def test_nightly_skips_when_disabled(db_sync):
    from backend.app.tasks.backup import backup_db_nightly

    s = db_sync.execute(
        select(ImportSettings).where(ImportSettings.id == 1)
    ).scalar_one()
    s.backup_db_nightly_enabled = False
    db_sync.commit()

    result = backup_db_nightly.apply().get()
    assert "skipped" in result and "disabled" in result["skipped"]


def test_nightly_skips_when_hour_mismatch(db_sync):
    from backend.app.tasks.backup import backup_db_nightly

    s = db_sync.execute(
        select(ImportSettings).where(ImportSettings.id == 1)
    ).scalar_one()
    s.backup_db_nightly_enabled = True
    s.backup_db_nightly_hour_utc = (datetime.now(UTC).hour + 12) % 24
    db_sync.commit()

    result = backup_db_nightly.apply().get()
    assert "skipped" in result and "hour=" in result["skipped"]


def test_nightly_dispatches_when_enabled_at_configured_hour(db_sync):
    from backend.app.tasks.backup import backup_db_nightly

    s = db_sync.execute(
        select(ImportSettings).where(ImportSettings.id == 1)
    ).scalar_one()
    s.backup_db_nightly_enabled = True
    s.backup_db_nightly_hour_utc = datetime.now(UTC).hour
    db_sync.commit()

    result = backup_db_nightly.apply().get()
    assert "dispatched" in result