// Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
// SPDX-License-Identifier: Apache-2.0

// snippet-start:[cognito.javascript.lambda-trigger.define-auth-challenge]
exports.handler = (event, context, callback) => {
  if (
    event.request.session.length == 1 &&
    event.request.session[0].challengeName == "SRP_A"
  ) {
    event.response.issueTokens = false;
    event.response.failAuthentication = false;
    event.response.challengeName = "PASSWORD_VERIFIER";
  } else if (
    event.request.session.length == 2 &&
    event.request.session[1].challengeName == "PASSWORD_VERIFIER" &&
    event.request.session[1].challengeResult == true
  ) {
    event.response.issueTokens = false;
    event.response.failAuthentication = false;
    event.response.challengeName = "CUSTOM_CHALLENGE";
  } else if (
    event.request.session.length == 3 &&
    event.request.session[2].challengeName == "CUSTOM_CHALLENGE" &&
    event.request.session[2].challengeResult == true
  ) {
    event.response.issueTokens = true;
    event.response.failAuthentication = false;
  } else {
    event.response.issueTokens = false;
    event.response.failAuthentication = true;
  }

  // Return to Amazon Cognito
  callback(null, event);
};
// snippet-end:[cognito.javascript.lambda-trigger.define-auth-challenge]