"""Retained terminal classification and filesystem-failure edge coverage."""

from __future__ import annotations

import os
from pathlib import Path

from testing.tests.test_hermes_cli_support import (
    _pending_terminal_record,
    lanes,
)


class _Snapshot:
    document = None
    invalid_reason = "malformed"

    def __init__(self):
        self.closed = 0

    def close(self):
        self.closed += 1


def test_retained_classifier_handles_missing_snapshot(tmp_path: Path, monkeypatch):
    path = tmp_path / "task.run-1.terminal.committed.json"
    monkeypatch.setattr(lanes, "_open_terminal_recovery_snapshot", lambda _path: None)
    assert lanes._quarantine_invalid_retained_terminal(path) == (True, False)


def test_retained_classifier_accepts_valid_committed_evidence(
    tmp_path: Path,
    monkeypatch,
):
    monkeypatch.setattr(lanes, "STATE_ROOT", tmp_path / "lanes")
    state_file = lanes.state_path("board", "task")
    path = lanes._terminal_path(state_file, 2, "committed")
    record = _pending_terminal_record("board", "task", 2, "accepted")
    record["kanban_state"] = "committed"
    lanes.atomic_json(path, record)
    assert lanes._quarantine_invalid_retained_terminal(path) == (False, False)


def test_retained_classifier_bounds_post_quarantine_stat_error(
    tmp_path: Path,
    monkeypatch,
):
    path = tmp_path / "task.run-3.terminal.committed.json"
    snapshot = _Snapshot()
    monkeypatch.setattr(
        lanes,
        "_open_terminal_recovery_snapshot",
        lambda _path: snapshot,
    )
    monkeypatch.setattr(lanes, "_quarantine_terminal", lambda *_args, **_kwargs: path)
    real_stat = Path.stat

    def fail_selected(candidate, *args, **kwargs):
        if candidate == path:
            raise PermissionError("denied")
        return real_stat(candidate, *args, **kwargs)

    monkeypatch.setattr(Path, "stat", fail_selected)
    assert lanes._quarantine_invalid_retained_terminal(path) == (True, False)
    assert snapshot.closed == 1


def test_gc_skips_symlink_board_and_disappearing_candidate(
    tmp_path: Path,
    monkeypatch,
):
    root = tmp_path / "lanes"
    root.mkdir()
    target = tmp_path / "target"
    target.mkdir()
    (root / "linked-board").symlink_to(target, target_is_directory=True)
    board = root / "board"
    board.mkdir()
    candidate = board / "task.candidate-1.json"
    candidate.write_text("{}", encoding="utf-8")
    monkeypatch.setattr(lanes, "STATE_ROOT", root)
    real_stat = Path.stat

    def disappear(selected, *args, **kwargs):
        if selected == candidate:
            raise FileNotFoundError
        return real_stat(selected, *args, **kwargs)

    monkeypatch.setattr(Path, "stat", disappear)
    assert lanes.gc_lane_artifacts() == 0


def test_gc_reports_quarantine_that_left_the_entry_in_place(
    tmp_path: Path,
    monkeypatch,
):
    """An invalid retained journal that survives quarantine is not counted."""
    root = tmp_path / "lanes"
    board = root / "board"
    board.mkdir(parents=True)
    retained = board / "task.run-1.terminal.committed.json"
    retained.write_text("{}", encoding="utf-8")
    monkeypatch.setattr(lanes, "STATE_ROOT", root)
    monkeypatch.setattr(lanes, "_quarantine_terminal", lambda *_a, **_k: retained)

    assert lanes.gc_lane_artifacts() == 0
    assert retained.exists()


def test_gc_bounds_unpinnable_staging_and_failed_nonregular_unlinks(
    tmp_path: Path,
    monkeypatch,
):
    """Unsnapshotable staging entries fall through to identity-safe removal."""
    root = tmp_path / "lanes"
    board = root / "board"
    board.mkdir(parents=True)
    dangling = board / ".retire.dangling"
    dangling.symlink_to(board / "missing-target")
    monkeypatch.setattr(lanes, "STATE_ROOT", root)
    attempts = []
    monkeypatch.setattr(
        lanes,
        "_unlink_artifact_if_same",
        lambda path, _observed: attempts.append(path.name) and False,
    )

    assert lanes.gc_lane_artifacts() == 0
    assert attempts == [".retire.dangling"]


def test_gc_keeps_entries_whose_capped_unlink_loses_the_race(
    tmp_path: Path,
    monkeypatch,
):
    """A lost inode race during count capping removes nothing else."""
    root = tmp_path / "lanes"
    board = root / "board"
    board.mkdir(parents=True)
    newer = board / "task.candidate-2.json"
    newer.write_text("{}", encoding="utf-8")
    older = board / "task.candidate-1.json"
    older.write_text("{}", encoding="utf-8")
    os.utime(older, (1, 1))
    monkeypatch.setattr(lanes, "STATE_ROOT", root)
    monkeypatch.setattr(
        lanes,
        "_unlink_artifact_if_same",
        lambda _path, _observed: False,
    )

    assert lanes.gc_lane_artifacts(now=100.0, max_age_seconds=10**9, max_count=1) == 0
    assert older.exists() and newer.exists()