content: /*
   * Licensed to the Apache Software Foundation (ASF) under one or more
   * contributor license agreements.  See the NOTICE file distributed with
   * this work for additional information regarding copyright ownership.
   * The ASF licenses this file to You under the Apache License, Version 2.0
   * (the "License"); you may not use this file except in compliance with
   * the License.  You may obtain a copy of the License at
   *
   *      http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  package org.apache.camel.example.mail.oauth2;
  
  import com.microsoft.aad.msal4j.ClientCredentialFactory;
  import com.microsoft.aad.msal4j.ClientCredentialParameters;
  import com.microsoft.aad.msal4j.ConfidentialClientApplication;
  import com.microsoft.aad.msal4j.IAuthenticationResult;
  import com.microsoft.aad.msal4j.IClientCredential;
  import org.apache.camel.component.mail.MailAuthenticator;
  
  import jakarta.mail.PasswordAuthentication;
  import java.net.MalformedURLException;
  import java.util.Collections;
  import java.util.Set;
  
  
  public class Oauth2ExchangeMailAuthenticator extends MailAuthenticator {
      private static final Set<String> SCOPE = Collections.singleton("https://outlook.office365.com/.default");
      private static final String AUTHORITY_BASE_URL = "https://login.microsoftonline.com/";
      private final String clientId;
      private final String clientSecret;
      private final String authority;
      private final String user;
  
  
      public Oauth2ExchangeMailAuthenticator(String tenantId, String clientId, String clientSecret, String user) {
          this.clientId = clientId;
          this.clientSecret = clientSecret;
          this.authority = AUTHORITY_BASE_URL + tenantId;
          this.user = user;
      }
  
      @Override
      public PasswordAuthentication getPasswordAuthentication() {
             String accessToken = acquireToken();
              return new PasswordAuthentication(user, accessToken);
      }
  
      private String acquireToken() {
  
          ConfidentialClientApplication cca;
          try {
              // This is the secret that is created in the Azure portal when registering the application
              IClientCredential credential = ClientCredentialFactory.createFromSecret(clientSecret);
  
              cca = ConfidentialClientApplication
                      .builder(clientId, credential)
                      .authority(authority)
                      .build();
          } catch (MalformedURLException e) {
              throw new RuntimeException(e);
          }
  
          // Client credential requests will by default try to look for a valid token in the
          // in-memory token cache. If found, it will return this token. If a token is not found, or the
          // token is not valid, it will fall back to acquiring a token from the AAD service. Although
          // not recommended unless there is a reason for doing so, you can skip the cache lookup
          // by using .skipCache(true) in ClientCredentialParameters.
          ClientCredentialParameters parameters =
                  ClientCredentialParameters
                          .builder(SCOPE)
                          .build();
  
          IAuthenticationResult result = cca.acquireToken(parameters).join();
          return result.accessToken();
      }
  }
  