// lib/auth.ts - 简化版认证工具
// 用于在 Next.js 中获取主应用的登录信息

export interface User {
  id: string;
  username: string;
  email: string;
  subscription_tier: string;
  avatar?: string;
}

export interface AuthInfo {
  isAuthenticated: boolean;
  user?: User;
  canAccessChat?: boolean;
  message?: string;
}

/**
 * 客户端检查认证状态
 * 直接调用 Flask 后端的 session 接口
 */
export async function checkAuth(): Promise<AuthInfo> {
  try {
    // 调用主应用的 session 检查接口
    const response = await fetch(`${process.env.NEXT_PUBLIC_API_URL}/api/auth/session`, {
      credentials: 'include', // 重要：携带 Cookie
      headers: {
        'Content-Type': 'application/json',
      },
    });

    if (!response.ok) {
      return { isAuthenticated: false };
    }

    const data = await response.json();

    // 检查是否登录
    if (!data.isAuthenticated || !data.user) {
      return {
        isAuthenticated: false,
        message: '请先登录'
      };
    }

    // 检查订阅权限
    const canAccessChat = ['premium', 'pro', 'enterprise'].includes(
      data.user.subscription_tier?.toLowerCase()
    );

    return {
      isAuthenticated: true,
      user: data.user,
      canAccessChat,
      message: canAccessChat ? undefined : '需要订阅才能使用 AI 助手功能'
    };
  } catch (error) {
    console.error('Auth check failed:', error);
    return {
      isAuthenticated: false,
      message: '认证服务暂时不可用'
    };
  }
}

/**
 * 调用 MCP API
 * 自动携带认证信息
 */
export async function callMCPApi(endpoint: string, options: RequestInit = {}) {
  const url = `${process.env.NEXT_PUBLIC_API_URL}${endpoint}`;

  const response = await fetch(url, {
    ...options,
    credentials: 'include', // 携带 Cookie
    headers: {
      'Content-Type': 'application/json',
      ...options.headers,
    },
  });

  if (response.status === 401) {
    // 未登录，跳转到主应用登录页
    window.location.href = `${process.env.NEXT_PUBLIC_MAIN_APP_URL}/auth/sign-in?redirect=/chat`;
    throw new Error('Unauthorized');
  }

  if (response.status === 403) {
    // 无权限，跳转到订阅页
    window.location.href = `${process.env.NEXT_PUBLIC_MAIN_APP_URL}/subscription?feature=ai-chat`;
    throw new Error('Subscription required');
  }

  return response;
}

/**
 * 登出（跳转到主应用的登出接口）
 */
export function logout() {
  window.location.href = `${process.env.NEXT_PUBLIC_MAIN_APP_URL}/api/auth/logout?redirect=/`;
}