const user = {
  name: '',
  email: '',
  age: null
};

const validator = {
  set(target, property, value) {
    if (property === 'email') {
      const emailRegex = /^[^\s@]+@[^\s@]+\.[^\s@]+$/;
      if (!emailRegex.test(value)) {
        console.error('无效的邮箱格式');
        return false;
      }
    }

    if (property === 'age') {
      if (typeof value !== 'number' || value < 0 || !Number.isInteger(value)) {
        console.error('年龄必须是非负整数');
        return false;
      }
    }

    target[property] = value;
    console.log(`${property} 已更新为: ${value}`);
    return true;
  }
};

const proxiedUser = new Proxy(user, validator);

proxiedUser.email = "test@example.com"; // 成功
proxiedUser.age = 25;                   // 成功
proxiedUser.age = -5;                   // 失败，报错
proxiedUser.email = "invalid-email";    // 失败，报错

const apiClient = {
  fetchUsers() {
    console.log("正在获取用户列表...");
  },
  createUser(data) {
    console.log("创建用户:", data);
  }
};

const authInterceptor = {
  get(target, prop) {
    const originalMethod = target[prop];
    if (typeof originalMethod === 'function') {
      return function(...args) {
        console.log(`[拦截] 调用方法: ${prop}`);
        
        const token = localStorage.getItem('auth_token');
        if (!token) {
          console.warn('未登录，禁止调用API');
          return;
        }

        console.log(`[授权] 使用Token: ${token.substring(0, 8)}...`);
        return originalMethod.apply(this, args);
      };
    }
    return originalMethod;
  }
};

const securedApi = new Proxy(apiClient, authInterceptor);

// 模拟设置token
localStorage.setItem('auth_token', 'abc123xyz987');

securedApi.fetchUsers();   // 正常执行
securedApi.createUser({}); // 正常执行

// 清除token测试
localStorage.removeItem('auth_token');
securedApi.fetchUsers();   // 提示未登录

function observe(data, onUpdate) {
  const handler = {
    set(target, property, value) {
      target[property] = value;
      onUpdate(property, value); // 数据变更通知
      return true;
    }
  };
  return new Proxy(data, handler);
}

const state = observe(
  { count: 0 },
  (key, val) => console.log(`状态更新: ${key} = ${val}`)
);

state.count++; // 输出：状态更新: count = 1
state.count = 10; // 输出：状态更新: count = 10