/**
 * OAuth2.0客户端类
 * 用于处理IDaaS OAuth2.0认证流程
 */

interface OAuthConfig {
  serverUrl: string;
  clientId: string;
  clientSecret: string;
  redirectUri: string;
  appId: string;
}

interface TokenResponse {
  access_token: string;
  token_type: string;
  refresh_token: string;
  expires_in: number;
  scope: string;
  jti: string;
}

interface UserInfoResponse {
  success: boolean;
  code: string;
  message: string | null;
  requestId: string;
  data: {
    sub: string;
    ou_id: string;
    nickname: string;
    phone_number: string;
    ou_name: string;
    email: string;
    username: string;
  };
}

export class OAuthClient {
  private config: OAuthConfig;

  constructor(config: OAuthConfig) {
    this.config = {
      ...config,
      serverUrl: config.serverUrl.replace(/\/$/, '') // 移除末尾斜杠
    };
  }

  /**
   * 生成授权URL
   * @param state 状态值，建议包含随机字符串和_idp后缀
   * @returns 授权URL
   */
  getAuthorizeUrl(state: string): string {
    const params = new URLSearchParams({
      response_type: 'code',
      scope: 'read',
      client_id: this.config.clientId,
      redirect_uri: this.config.redirectUri,
      state: state
    });

    return `${this.config.serverUrl}/oauth/authorize?${params.toString()}`;
  }

  /**
   * 获取访问令牌
   * @param code 授权码
   * @returns 访问令牌响应
   */
  async getAccessToken(code: string): Promise<TokenResponse | null> {
    const url = `${this.config.serverUrl}/oauth/token`;
    const data = new URLSearchParams({
      grant_type: 'authorization_code',
      code: code,
      client_id: this.config.clientId,
      client_secret: this.config.clientSecret,
      redirect_uri: this.config.redirectUri
    });

    try {
      const response = await fetch(url, {
        method: 'POST',
        headers: {
          'Content-Type': 'application/x-www-form-urlencoded'
        },
        body: data
      });

      if (!response.ok) {
        const errorData = await response.json();
        console.error('获取访问令牌失败:', errorData);
        return null;
      }

      return await response.json() as TokenResponse;
    } catch (error) {
      console.error('获取访问令牌网络错误:', error);
      return null;
    }
  }

  /**
   * 获取用户信息
   * @param accessToken 访问令牌
   * @returns 用户信息响应
   */
  async getUserInfo(accessToken: string): Promise<UserInfoResponse | null> {
    const url = `${this.config.serverUrl}/api/bff/v1.2/oauth2/userinfo`;

    try {
      const response = await fetch(url, {
        headers: {
          'Authorization': `Bearer ${accessToken}`
        }
      });

      if (!response.ok) {
        console.error('获取用户信息失败:', response.status, response.statusText);
        return null;
      }

      return await response.json() as UserInfoResponse;
    } catch (error) {
      console.error('获取用户信息网络错误:', error);
      return null;
    }
  }

  /**
   * 单点登出
   * @param accessToken 访问令牌
   * @param redirectUrl 登出后重定向URL
   * @returns 登出是否成功
   */
  async logout(accessToken: string, redirectUrl: string): Promise<boolean> {
    const url = `${this.config.serverUrl}/public/sp/slo/${this.config.appId}`;
    const data = new URLSearchParams({
      access_token: accessToken,
      redirect_url: redirectUrl
    });

    try {
      const response = await fetch(url, {
        method: 'POST',
        headers: {
          'Content-Type': 'application/x-www-form-urlencoded'
        },
        body: data
      });

      return response.ok;
    } catch (error) {
      console.error('登出失败:', error);
      return false;
    }
  }

  /**
   * 生成随机状态值
   * @returns 状态值字符串
   */
  generateState(): string {
    const randomStr = Math.random().toString(36).substring(2, 15) + 
                     Math.random().toString(36).substring(2, 15);
    return `${randomStr}_idp`;
  }
}

/**
 * OAuth2.0工具函数
 */
export const oauthUtils = {
  /**
   * 从URL中提取查询参数
   * @param url URL字符串
   * @returns 查询参数对象
   */
  getQueryParams(url: string): Record<string, string> {
    const params: Record<string, string> = {};
    const urlObj = new URL(url);
    
    for (const [key, value] of urlObj.searchParams) {
      params[key] = value;
    }
    
    return params;
  },

  /**
   * 验证状态值
   * @param state 返回的状态值
   * @param expectedState 期望的状态值
   * @returns 是否匹配
   */
  validateState(state: string, expectedState: string): boolean {
    return state === expectedState;
  },

  /**
   * 检查访问令牌是否过期
   * @param tokenInfo 令牌信息
   * @param issuedAt 令牌颁发时间戳
   * @returns 是否过期
   */
  isTokenExpired(tokenInfo: TokenResponse, issuedAt: number): boolean {
    const now = Date.now();
    const expiresAt = issuedAt + (tokenInfo.expires_in * 1000);
    return now >= expiresAt;
  }
};