import { userApi, User, RegisterRequest as ApiRegisterRequest, LoginResponse as ApiLoginResponse, TokenVerifyResponse } from './userApi';

// 用户信息接口（兼容现有代码）
export interface UserInfo {
  id: string;
  nickname: string;
  phone?: string;
  email?: string;
  avatar?: string;
  registrationDate?: string;
  apikey?: string; // 添加API密钥字段
  realName?: string; // 真实姓名
  isVerified?: string; // 认证状态
  verifiedAt?: string; // 认证时间
}

// 登录响应接口（兼容现有代码）
export interface LoginResponse {
  code: number;
  message: string;
  data: {
    token: string;
    refreshToken?: string;
    expiresIn?: number;
    user: UserInfo;
  };
}

// 注册请求接口
export interface RegisterRequest {
  username: string;
  password: string;
  email?: string;
  phone?: string;
  nickname?: string;
  schoolEmail?: string; // 学校邮箱（可选）
  sms_code?: string;
  email_code?: string;
}

// 注册响应接口
export interface RegisterResponse {
  code: number;
  message: string;
  data: {
    userId: string;
    user?: UserInfo;
  };
}

// 转换后端用户数据为前端格式
function convertUserToUserInfo(user: User): UserInfo {
  return {
    id: user.id,
    nickname: user.nickname,
    phone: user.phone || undefined,
    email: user.email || undefined,
    avatar: user.avatar || undefined,
    registrationDate: user.registration_date,
    apikey: user.apikey || undefined,
    realName: user.real_name || undefined,
    isVerified: user.is_verified || 'unverified',
    verifiedAt: user.verified_at || undefined,
  };
}

// Token 存储键名
const TOKEN_KEY = 'aigc_space_token';
const REFRESH_TOKEN_KEY = 'aigc_space_refresh_token';
const USER_INFO_KEY = 'aigc_space_user_info';
const API_BASE_URL = import.meta.env.VITE_API_BASE_URL ?? 'http://localhost:8010';

// 认证状态变化事件名
const AUTH_CHANGE_EVENT = 'auth_state_change';

/**
 * 鉴权服务类
 * 负责管理用户认证、token 存储和 API 请求鉴权
 */
class AuthService {
  private token: string | null = null;
  private refreshToken: string | null = null;
  private userInfo: UserInfo | null = null;

  constructor() {
    // 从 localStorage 恢复 token 和用户信息
    this.loadFromStorage();
  }

  /**
   * 订阅认证状态变化
   * @param callback 状态变化时的回调函数
   * @returns 取消订阅的函数
   */
  subscribe(callback: () => void): () => void {
    const handler = (e: Event) => {
      // console.log('[AuthService] event handler triggered');
      callback();
    };
    window.addEventListener(AUTH_CHANGE_EVENT, handler);
    console.log('[AuthService] subscribed to', AUTH_CHANGE_EVENT);
    return () => {
      window.removeEventListener(AUTH_CHANGE_EVENT, handler);
      // console.log('[AuthService] unsubscribed from', AUTH_CHANGE_EVENT);
    };
  }

  /**
   * 通知所有订阅者状态已变化
   */
  private notifyListeners(): void {
    console.log('[AuthService] notifyListeners called');
    // 触发自定义事件，用于跨组件通信
    if (typeof window !== 'undefined') {
      const event = new CustomEvent(AUTH_CHANGE_EVENT);
      console.log('[AuthService] dispatching event:', AUTH_CHANGE_EVENT);
      window.dispatchEvent(event);
    }
  }

  /**
   * 从 localStorage 加载 token 和用户信息
   */
  private loadFromStorage(): void {
    if (typeof window !== 'undefined') {
      const token = localStorage.getItem(TOKEN_KEY);
      const refreshToken = localStorage.getItem(REFRESH_TOKEN_KEY);
      
      // 确保 token 不是空字符串
      this.token = token && token.trim() !== '' ? token : null;
      this.refreshToken = refreshToken && refreshToken.trim() !== '' ? refreshToken : null;
      
      const userInfoStr = localStorage.getItem(USER_INFO_KEY);
      if (userInfoStr) {
        try {
          this.userInfo = JSON.parse(userInfoStr);
        } catch (e) {
          console.error('Failed to parse user info from storage:', e);
          this.userInfo = null;
        }
      }
    }
  }

  /**
   * 保存 token 和用户信息到 localStorage
   */
  private saveToStorage(token: string, userInfo: UserInfo, refreshToken?: string): void {
    if (typeof window !== 'undefined') {
      localStorage.setItem(TOKEN_KEY, token);
      if (refreshToken) {
        localStorage.setItem(REFRESH_TOKEN_KEY, refreshToken);
      }
      localStorage.setItem(USER_INFO_KEY, JSON.stringify(userInfo));
    }
    this.token = token;
    this.refreshToken = refreshToken || null;
    this.userInfo = userInfo;
    // 通知订阅者状态已变化
    this.notifyListeners();
  }

  /**
   * 清除存储的 token 和用户信息
   */
  private clearStorage(): void {
    console.log('[AuthService] clearStorage called');
    if (typeof window !== 'undefined') {
      localStorage.removeItem(TOKEN_KEY);
      localStorage.removeItem(REFRESH_TOKEN_KEY);
      localStorage.removeItem(USER_INFO_KEY);
      console.log('[AuthService] localStorage cleared');
    }
    this.token = null;
    this.refreshToken = null;
    this.userInfo = null;
    console.log('[AuthService] instance state cleared, notifying listeners');
    // 通知订阅者状态已变化
    this.notifyListeners();
  }

  /**
   * SSO一键登录（通过学校网站token）
   * @param ssoToken 学校网站提供的SSO token
   * @returns Promise<LoginResponse>
   */
  async ssoLogin(ssoToken: string): Promise<LoginResponse> {
    try {
      const response = await fetch(`${API_BASE_URL}/api/auth/verify`, {
        method: 'GET',
        headers: {
          'Content-Type': 'application/json',
          Authorization: `Bearer ${ssoToken}`,
        },
      });

      if (!response.ok) {
        return {
          code: response.status,
          message: 'SSO登录失败，票据已失效或无效',
          data: {
            token: '',
            user: {
              id: '',
              nickname: '',
            },
          },
        };
      }

      const verifyResult = (await response.json()) as TokenVerifyResponse;
      const userInfo = convertUserToUserInfo(verifyResult.user);
      this.saveToStorage(ssoToken, userInfo);

      return {
        code: 200,
        message: 'SSO登录成功',
        data: {
          token: ssoToken,
          user: userInfo,
        },
      };
    } catch (error) {
      return {
        code: 500,
        message: error instanceof Error ? error.message : 'SSO登录失败',
        data: {
          token: '',
          user: {
            id: '',
            nickname: '',
          },
        },
      };
    }
  }

  /**
   * 查询后端 SSO 配置（含是否启用、CAS 登录地址等）
   */
  async getSsoConfig(): Promise<{ sso_enabled: boolean; cas_login_url: string } | null> {
    try {
      const res = await fetch(`${API_BASE_URL}/api/sso/config`);
      if (!res.ok) return null;
      return await res.json();
    } catch {
      return null;
    }
  }

  /**
   * 查询后端 SSO 是否启用
   */
  async isSsoEnabled(): Promise<boolean> {
    const cfg = await this.getSsoConfig();
    if (cfg === null) return false; // 请求失败时默认不启用SSO，跳普通登录页
    return cfg.sso_enabled === true;
  }

  /**
   * 登录
   * @param username 用户名或手机号
   * @param password 密码
   * @param keyId 会话密钥ID
   * @returns Promise<LoginResponse>
   */
  async login(username: string, password: string, keyId: string | null = null): Promise<LoginResponse> {
    try {
      const apiResponse = await userApi.login(username, password, keyId);
      
      const userInfo = convertUserToUserInfo(apiResponse.user);
      
      // 保存 token 和用户信息
      this.saveToStorage(apiResponse.access_token, userInfo);

      return {
        code: 200,
        message: '登录成功',
        data: {
          token: apiResponse.access_token,
          user: userInfo,
        }
      };
    } catch (error) {
      return {
        code: 401,
        message: error instanceof Error ? error.message : '登录失败',
        data: {
          token: '',
          user: {
            id: '',
            nickname: '',
          }
        }
      };
    }
  }

  /**
   * 注册
   * @param registerData 注册信息
   * @param keyId 会话密钥ID
   * @returns Promise<RegisterResponse>
   */
  async register(registerData: RegisterRequest, keyId: string | null = null): Promise<RegisterResponse> {
    try {
      const apiRegisterData: ApiRegisterRequest = {
        username: registerData.username,
        password: registerData.password,
        nickname: registerData.nickname || registerData.username,
        email: registerData.email || registerData.schoolEmail,
        phone: registerData.phone,
        sms_code: registerData.sms_code,
        email_code: registerData.email_code,
      };

      const user = await userApi.register(apiRegisterData, keyId);
      const userInfo = convertUserToUserInfo(user);

      return {
        code: 200,
        message: '注册成功',
        data: {
          userId: user.id,
          user: userInfo,
        }
      };
    } catch (error) {
      return {
        code: 400,
        message: error instanceof Error ? error.message : '注册失败',
        data: {
          userId: '',
        }
      };
    }
  }

  /**
   * 登出
   * @param callApi 是否调用后端API（默认true）
   */
  async logout(callApi: boolean = true): Promise<void> {
    console.log('[AuthService] logout called');
    
    // 尝试调用后端登出API
    if (callApi && this.token) {
      try {
        await userApi.logout();
        console.log('[AuthService] backend logout successful');
      } catch (error) {
        console.warn('[AuthService] backend logout failed:', error);
        // 即使后端调用失败，也继续清理本地状态
      }
    }
    
    this.clearStorage();
  }

  /**
   * 本地登出后跳转CAS统一认证注销
   */
  async logoutAndRedirectToCas(): Promise<void> {
    await this.logout(true);
    if (typeof window !== 'undefined') {
      const cfg = await this.getSsoConfig();
      if (cfg?.sso_enabled) {
        const casLogoutUrl = cfg.cas_login_url.replace(/\/login$/, '/logout');
        window.location.href = casLogoutUrl;
      } else {
        window.location.href = '/login';
      }
    }
  }

  /**
   * 验证Token是否有效
   * @returns Promise<{valid: boolean, user?: UserInfo}>
   */
  async verifyToken(): Promise<{ valid: boolean; user?: UserInfo }> {
    if (!this.token) {
      return { valid: false };
    }

    try {
      const response = await userApi.verifyToken();
      if (response.valid && response.user) {
        const userInfo = convertUserToUserInfo(response.user);
        // 更新本地存储的用户信息
        this.userInfo = userInfo;
        if (typeof window !== 'undefined') {
          localStorage.setItem(USER_INFO_KEY, JSON.stringify(userInfo));
        }
        return { valid: true, user: userInfo };
      }
      return { valid: false };
    } catch (error) {
      console.error('[AuthService] Token verification failed:', error);
      return { valid: false };
    }
  }

  /**
   * 刷新Token并延长有效期
   * @returns Promise<boolean> 是否刷新成功
   */
  async refreshTokenAndExtend(): Promise<boolean> {
    if (!this.token) {
      return false;
    }

    try {
      const response = await userApi.refreshToken();
      const userInfo = convertUserToUserInfo(response.user);
      
      // 保存新的Token和用户信息
      this.saveToStorage(response.access_token, userInfo);
      console.log('[AuthService] Token refreshed successfully');
      return true;
    } catch (error) {
      console.error('[AuthService] Token refresh failed:', error);
      return false;
    }
  }

  /**
   * 检查并刷新Token
   * 如果Token有效则刷新延长有效期，如果无效则清除登录状态
   * @returns Promise<boolean> Token是否有效
   */
  async checkAndRefreshToken(): Promise<boolean> {
    const verifyResult = await this.verifyToken();
    
    if (!verifyResult.valid) {
      // Token无效，清除登录状态（不调用后端API，因为Token已经无效）
      await this.logout(false);
      return false;
    }

    // Token有效，刷新延长有效期
    const refreshed = await this.refreshTokenAndExtend();
    if (!refreshed) {
      // 刷新失败但验证成功，保持当前状态
      console.warn('[AuthService] Token valid but refresh failed');
    }
    
    return true;
  }

  /**
   * 获取当前 token
   * @returns token 字符串或 null
   */
  getToken(): string | null {
    return this.token;
  }

  /**
   * 获取刷新 token
   * @returns refreshToken 字符串或 null
   */
  getRefreshToken(): string | null {
    return this.refreshToken;
  }

  /**
   * 获取当前用户信息
   * @returns 用户信息对象或 null
   */
  getUserInfo(): UserInfo | null {
    return this.userInfo;
  }

  /**
   * 检查是否已登录
   * @returns 是否已登录
   */
  isAuthenticated(): boolean {
    return this.token !== null && this.userInfo !== null;
  }

  /**
   * 刷新 token
   * @returns Promise<string> 新的 token
   */
  async refreshAccessToken(): Promise<string> {
    if (!this.refreshToken) {
      throw new Error('No refresh token available');
    }

    // 模拟网络延迟
    await new Promise(resolve => setTimeout(resolve, 300));

    // 模拟刷新 token API 调用
    const newToken = `mock_token_${Date.now()}_${Math.random().toString(36).substr(2, 9)}`;
    
    if (typeof window !== 'undefined') {
      localStorage.setItem(TOKEN_KEY, newToken);
    }
    this.token = newToken;

    return newToken;
  }

  /**
   * 设置 token（用于外部设置，如从其他来源获取 token）
   * @param token token 字符串
   * @param userInfo 用户信息
   */
  setToken(token: string, userInfo: UserInfo): void {
    this.saveToStorage(token, userInfo);
  }

  /**
   * 获取 Authorization header 值
   * @returns Authorization header 字符串，格式：'Bearer {token}'
   */
  getAuthHeader(): string | null {
    if (!this.token || this.token.trim() === '') {
      return null;
    }
    return `Bearer ${this.token}`;
  }
}

// 导出单例
export const authService = new AuthService();

// 导出类型
export type { UserInfo, LoginResponse, RegisterRequest, RegisterResponse };