# -*- coding: utf-8 -*-
"""auth_system 同步栈的读写并发验证：读不持锁、写仍串行（WAL）。"""
import sqlite3
import threading
import time

import pytest

import auth_system


@pytest.fixture()
def temp_site(tmp_path, monkeypatch):
    monkeypatch.setattr(auth_system.db, 'DATA_DIR', tmp_path)
    monkeypatch.setattr(auth_system.db, 'DB_PATH', tmp_path / 'site.db')
    monkeypatch.setattr(auth_system.db, 'BACKUP_DIR', tmp_path / 'backups')
    monkeypatch.setattr(auth_system.db, 'SECRET_KEY_PATH', tmp_path / 'secret.key')
    auth_system.init_db()
    return tmp_path / 'site.db'


def test_q_does_not_hold_lock(temp_site):
    """_q 读不应获取 _DB_LOCK（否则读会被写挡住）。"""
    # 让另一个线程持有写锁，读仍应在短时间返回（不被阻塞）
    held = threading.Event()
    release = threading.Event()

    def holder():
        with auth_system._DB_LOCK:
            held.set()
            release.wait(5)

    t = threading.Thread(target=holder, daemon=True)
    t.start()
    held.wait(2)
    try:
        start = time.monotonic()
        rows = auth_system._q('SELECT COUNT(*) AS n FROM users')
        elapsed = time.monotonic() - start
        assert rows is not None
        assert elapsed < 1.0, f'读被写锁阻塞了 {elapsed:.2f}s（WAL 下不应发生）'
    finally:
        release.set()
        t.join(2)


def test_concurrent_reads_and_writes(temp_site):
    """多读线程 + 一个写线程并发：无异常、结果一致。"""
    errors = []
    stop = threading.Event()

    def writer():
        try:
            for i in range(50):
                auth_system.set_setting(f'k{i}', str(i))
        except Exception as e:
            errors.append(('w', e))
        finally:
            stop.set()

    def reader():
        while not stop.is_set():
            try:
                auth_system.get_setting('k0')
            except Exception as e:
                errors.append(('r', e))

    ws = threading.Thread(target=writer, daemon=True)
    rs = [threading.Thread(target=reader, daemon=True) for _ in range(4)]
    ws.start()
    for r in rs:
        r.start()
    ws.join(20)
    for r in rs:
        r.join(2)

    assert not errors, f'并发读写异常: {errors[:3]}'
    assert auth_system.get_setting('k49') == '49'


def test_wal_enabled(temp_site):
    conn = sqlite3.connect(str(temp_site))
    try:
        mode = conn.execute('PRAGMA journal_mode').fetchone()[0]
    finally:
        conn.close()
    assert str(mode).lower() == 'wal'