.build();
    this.clientId = clientId;
    this.clientSecret = clientSecret;
    this.port = port;
  }

  /** See https://api.slack.com/docs/oauth. */
  public HttpUrl authorizeUrl(String scopes, HttpUrl redirectUrl, ByteString state, String team) {
    HttpUrl.Builder builder = baseUrl.newBuilder("/oauth/authorize")
        .addQueryParameter("client_id", clientId)

      sessionFactory.start();
    }

    HttpUrl authorizeUrl = sessionFactory.newAuthorizeUrl(scopes, team, session -> {
      initOauthSession(session);
      System.out.printf("session granted: %s\n", session);
    });

    System.out.printf("open this URL in a browser: %s\n", authorizeUrl);
  }

  /** Set the OAuth session for this client. */

    if (mockWebServer == null) throw new IllegalStateException();

    ByteString state = randomToken();
    synchronized (this) {
      listeners.put(state, listener);
    }

    return slackApi.authorizeUrl(scopes, redirectUrl(), state, team);
  }

  private ByteString randomToken() {
    byte[] bytes = new byte[16];
    secureRandom.nextBytes(bytes);
    return ByteString.of(bytes);
  }