"""Tests for the last backup state file and --last-backup"""

import os
import pwd
from collections.abc import Callable
from datetime import datetime, timedelta
from pathlib import Path

import pytest

from simple_backup import simple_backup as sb

DESTINATION = '/backups/simple_backup/2026-10-25_10-00-00'


@pytest.fixture(autouse=True)
def as_user(monkeypatch: pytest.MonkeyPatch) -> None:
    """Run as a non-root user (the tests may run as root in a chroot)"""

    monkeypatch.setattr(os, 'geteuid', lambda: 1000)
    monkeypatch.setenv('USER', 'user')


@pytest.fixture
def state(tmp_path: Path) -> Path:
    return tmp_path / 'state' / 'simple_backup' / 'last_backup'


def write_state(state: Path, text: str) -> None:
    state.parent.mkdir(parents=True)
    state.write_text(text)


def test_write(state: Path) -> None:
    sb._write_state(None, DESTINATION)

    time, destination = state.read_text().splitlines()
    assert abs(datetime.now().astimezone() - datetime.fromisoformat(time)) < timedelta(minutes=1)
    assert destination == DESTINATION
    # No temporary file left behind
    assert os.listdir(state.parent) == ['last_backup']


def test_overwrite(state: Path) -> None:
    write_state(state, '2026-10-01T10:00:00+02:00\n/old\n')

    sb._write_state(None, DESTINATION)

    assert state.read_text().splitlines()[1] == DESTINATION


def test_relative_xdg_state_home_ignored(monkeypatch: pytest.MonkeyPatch, tmp_path: Path) -> None:
    monkeypatch.setenv('XDG_STATE_HOME', 'relative')
    monkeypatch.setenv('HOME', str(tmp_path / 'home'))

    sb._write_state(None, DESTINATION)

    assert (tmp_path / 'home' / '.local' / 'state' / 'simple_backup' / 'last_backup').exists()


def test_write_error(monkeypatch: pytest.MonkeyPatch, tmp_path: Path, caplog: pytest.LogCaptureFixture) -> None:
    # A file where the state directory should be
    (tmp_path / 'not a dir').write_text('')
    monkeypatch.setenv('XDG_STATE_HOME', str(tmp_path / 'not a dir'))

    sb._write_state(None, DESTINATION)

    assert 'Cannot save the time of the last backup' in caplog.text


def test_root_writes_as_user(monkeypatch: pytest.MonkeyPatch, tmp_path: Path) -> None:
    calls: list[tuple[str, int]] = []
    egid = os.getegid()
    owner = pwd.struct_passwd(('user', 'x', 1000, 1001, '', str(tmp_path / 'home'), '/bin/sh'))

    monkeypatch.setattr(os, 'geteuid', lambda: 0)
    monkeypatch.setattr(pwd, 'getpwnam', lambda name: owner)
    monkeypatch.setattr(os, 'seteuid', lambda uid: calls.append(('euid', uid)))
    monkeypatch.setattr(os, 'setegid', lambda gid: calls.append(('egid', gid)))

    sb._write_state('user', DESTINATION)

    # Root's XDG_STATE_HOME is not used
    assert (tmp_path / 'home' / '.local' / 'state' / 'simple_backup' / 'last_backup').exists()
    assert calls == [('egid', 1001), ('euid', 1000), ('euid', 0), ('egid', egid)]


class TestStateOwner:
    def test_non_root(self) -> None:
        assert sb._state_owner('user') is None

    @pytest.mark.parametrize('name, expected', [('user', 'user'), ('root', None), ('unknown', None), (None, None)])
    def test_root(self, monkeypatch: pytest.MonkeyPatch, name: str | None, expected: str | None) -> None:
        users = {'user': pwd.struct_passwd(('user', 'x', 1000, 1000, '', '/home/user', '/bin/sh')),
                 'root': pwd.struct_passwd(('root', 'x', 0, 0, '', '/root', '/bin/sh'))}

        def getpwnam(name: str) -> pwd.struct_passwd:
            if name not in users:
                raise KeyError(name)

            return users[name]

        monkeypatch.setattr(os, 'geteuid', lambda: 0)
        monkeypatch.setattr(pwd, 'getpwnam', getpwnam)

        owner = sb._state_owner(name)
        assert (owner.pw_name if owner is not None else None) == expected


class TestShow:
    @pytest.mark.parametrize('days, age', [(0, 'today'), (1, 'yesterday'), (3, '3 days ago')])
    def test_age(self, run_cli: Callable[..., int], state: Path, capsys: pytest.CaptureFixture[str],
                 days: int, age: str) -> None:
        completed = (datetime.now() - timedelta(days=days)).replace(hour=12, minute=30).astimezone()
        write_state(state, f'{completed.isoformat(timespec="seconds")}\n{DESTINATION}\n')

        assert run_cli('--last-backup') == 0
        assert capsys.readouterr().out == \
            f'Last backup: {completed:%Y-%m-%d} 12:30 ({age})\nDirectory: {DESTINATION}\n'

    def test_after_write(self, run_cli: Callable[..., int], capsys: pytest.CaptureFixture[str]) -> None:
        sb._write_state(None, DESTINATION)

        assert run_cli('--last-backup') == 0
        assert '(today)' in capsys.readouterr().out

    def test_no_backup(self, run_cli: Callable[..., int], capsys: pytest.CaptureFixture[str]) -> None:
        assert run_cli('--last-backup') == 1
        assert capsys.readouterr().out == 'No backup recorded yet\n'

    @pytest.mark.parametrize('text', ['', '2026-10-25T10:00:00+02:00\n', 'yesterday\n/backups\n'])
    def test_bad_file(self, run_cli: Callable[..., int], state: Path, capsys: pytest.CaptureFixture[str],
                      text: str) -> None:
        write_state(state, text)

        assert run_cli('--last-backup') == 1
        assert 'Cannot read' in capsys.readouterr().err