// 简单的本地账号系统：用户数据保存在 localStorage
(function () {
  const USERS_KEY = 'tp_users';
  const SESSION_KEY = 'tp_session';

  function getUsers() {
    try { return JSON.parse(localStorage.getItem(USERS_KEY)) || {}; }
    catch (e) { return {}; }
  }
  function saveUsers(users) {
    localStorage.setItem(USERS_KEY, JSON.stringify(users));
  }

  const Auth = {
    currentUser() {
      return localStorage.getItem(SESSION_KEY) || null;
    },
    login(username, password) {
      const users = getUsers();
      if (!users[username]) return { ok: false, msg: '用户不存在，请先注册' };
      if (users[username] !== password) return { ok: false, msg: '密码错误' };
      localStorage.setItem(SESSION_KEY, username);
      return { ok: true };
    },
    register(username, password) {
      if (!username || !password) return { ok: false, msg: '用户名和密码不能为空' };
      const users = getUsers();
      if (users[username]) return { ok: false, msg: '用户已存在' };
      users[username] = password;
      saveUsers(users);
      localStorage.setItem(SESSION_KEY, username);
      return { ok: true };
    },
    logout() {
      localStorage.removeItem(SESSION_KEY);
    },
    // 每个用户独立的数据命名空间
    dataKey(name) {
      const u = this.currentUser();
      return u ? `tp_data_${u}_${name}` : null;
    }
  };

  window.Auth = Auth;
})();