import { WebApiConfiguration } from './web-api-configuration';
import { AccessTokenProvider, AccessToken } from './access-token-provider';

/**
 * @export
 * @class OauthProvider
 * @implements {OathInterface}
 */
export class OauthProvider implements OathInterface {
  accessTokenProvider: AccessTokenProvider;
  config: WebApiConfiguration;

  /**
   * Creates an instance of OauthProvider.
   * @param {AccessTokenProvider} accessTokenProvider 
   * @param {WebApiConfiguration} config 
   * 
   * @memberOf OauthProvider
   */
  constructor(accessTokenProvider: AccessTokenProvider, config: WebApiConfiguration) {
    this.accessTokenProvider = accessTokenProvider;
    this.config = config;
  }

  /**
   * Returns url for authentication based on provided config
   * @returns {string} 
   * 
   * @memberOf OauthProvider
   */
  getOauth2Url(): string {
    if (this.config.oauth2.clientSecret) {
      return `${this.config.environment.oAuth2ContextBaseUrl}/auth?response_type=code&client_id=${this.config.oauth2.clientId}&access_type=offline&redirect_uri=${this.config.oauth2.redirectUri}`;
    }

    return `${this.config.environment.oAuth2ContextBaseUrl}/auth?response_type=token&client_id=${this.config.oauth2.clientId}&redirect_uri=${this.config.oauth2.redirectUri}`
  }

  /**
   * Parses callback uri and extracts information that is used for requesting access token
   * 
   * @param {string} url 
   * @returns {Promise<AccessToken>} 
   * 
   * @memberOf OauthProvider
   */
  processRedirect(url: string): Promise<AccessToken> {
    if (this.config.oauth2.clientSecret) {
      try {
        var code: string = /code=([^&]*)/.exec(url)[1];
      } catch (e) {
        throw new Error('Passed url does not contain code.');
      }

      this.accessTokenProvider.useCode(code);

      return this.accessTokenProvider.getAccessToken();
    }

    try {
      var expiration: any = /expires_in=([^&]*)/.exec(url)[1];
      var accessToken = {
        token: /access_token=([^&]*)/.exec(url)[1],
        tokenType: /token_type=([^&]*)/.exec(url)[1],
        expiresIn: Date.now() + (expiration * 1000) - 5000,
      }
    } catch (e) {
      throw new Error('Passed url does not contain access token, token type or expiration.');
    }

    this.accessTokenProvider.useAccessToken(accessToken);

    return this.accessTokenProvider.getAccessToken();
  }
}

/**
 * @export
 * @interface OathInterface
 */
export interface OathInterface {
  getOauth2Url(): string;
  processRedirect(url: string): any;
}