from __future__ import annotations

import os
from pathlib import Path

import pytest

from k1link.device_plugins.xgrids_k1.archive import discover_legacy_viewer_sessions
from k1link.sessions import ActiveSessionLease, recover_stale_active_session_marker
from k1link.sessions import active as active_session_module


def test_active_session_lease_hides_live_evidence_until_release(tmp_path: Path) -> None:
    sessions = tmp_path / "sessions"
    session = sessions / "20260717T011050Z_viewer_live"

    lease = ActiveSessionLease.acquire(sessions, session)
    try:
        session.mkdir()
        capture = session / "captures" / "mqtt_live"
        capture.mkdir(parents=True)
        (capture / "mqtt.raw.k1mqtt").write_bytes(b"K1MQTT\x00unfinished")
        candidates = discover_legacy_viewer_sessions(sessions)
        assert candidates == ()
        assert recover_stale_active_session_marker(sessions) is False
    finally:
        lease.release()

    assert not (sessions / ".current_session").exists()
    candidates = discover_legacy_viewer_sessions(sessions)
    assert len(candidates) == 1
    assert candidates[0].session_id == session.name
    assert candidates[0].replayable is False


def test_startup_recovery_removes_only_an_unlocked_stale_marker(tmp_path: Path) -> None:
    sessions = tmp_path / "sessions"
    sessions.mkdir()
    marker = sessions / ".current_session"
    marker.write_text("20260717T011050Z_viewer_live\n", encoding="utf-8")

    assert recover_stale_active_session_marker(sessions) is True
    assert not marker.exists()
    assert recover_stale_active_session_marker(sessions) is False


def test_active_session_release_retries_unlink_without_dropping_lock(
    tmp_path: Path,
    monkeypatch: pytest.MonkeyPatch,
) -> None:
    sessions = tmp_path / "sessions"
    session = sessions / "20260812T231000Z_viewer_live"
    lease = ActiveSessionLease.acquire(sessions, session)
    marker = sessions / ".current_session"
    original_unlink = Path.unlink
    attempts = 0

    def fail_once(path: Path, *args: object, **kwargs: object) -> None:
        nonlocal attempts
        if path == marker and attempts == 0:
            attempts += 1
            raise OSError("injected marker unlink failure")
        original_unlink(path, *args, **kwargs)

    monkeypatch.setattr(Path, "unlink", fail_once)
    with pytest.raises(OSError, match="injected marker unlink failure"):
        lease.release()

    assert marker.exists()
    assert lease._released is False  # noqa: SLF001
    os.fstat(lease._descriptor)  # noqa: SLF001
    assert recover_stale_active_session_marker(sessions) is False

    lease.release()
    assert lease._released is True  # noqa: SLF001
    assert not marker.exists()


def test_active_session_release_retries_directory_fsync_after_unlink(
    tmp_path: Path,
    monkeypatch: pytest.MonkeyPatch,
) -> None:
    sessions = tmp_path / "sessions"
    session = sessions / "20260812T231100Z_viewer_live"
    lease = ActiveSessionLease.acquire(sessions, session)
    original_fsync = active_session_module._fsync_directory_strict
    attempts = 0

    def fail_once(path: Path) -> None:
        nonlocal attempts
        if attempts == 0:
            attempts += 1
            raise OSError("injected directory fsync failure")
        original_fsync(path)

    monkeypatch.setattr(active_session_module, "_fsync_directory_strict", fail_once)
    with pytest.raises(OSError, match="injected directory fsync failure"):
        lease.release()

    assert lease._marker_removed is True  # noqa: SLF001
    assert lease._released is False  # noqa: SLF001
    os.fstat(lease._descriptor)  # noqa: SLF001

    lease.release()
    lease.release()
    assert lease._released is True  # noqa: SLF001