/**
    * This file Copyright (c) 2017 Magnolia International
    * Ltd.  (http://www.magnolia-cms.com). All rights reserved.
    *
    *
    * This file is dual-licensed under both the Magnolia
    * Network Agreement and the GNU General Public License.
    * You may elect to use one or the other of these licenses.
    *
   * This file is distributed in the hope that it will be
   * useful, but AS-IS and WITHOUT ANY WARRANTY; without even the
   * implied warranty of MERCHANTABILITY or FITNESS FOR A
   * PARTICULAR PURPOSE, TITLE, or NONINFRINGEMENT.
   * Redistribution, except as permitted by whichever of the GPL
   * or MNA you select, is prohibited.
   *
   * 1. For the GPL license (GPL), you can redistribute and/or
   * modify this file under the terms of the GNU General
   * Public License, Version 3, as published by the Free Software
   * Foundation.  You should have received a copy of the GNU
   * General Public License, Version 3 along with this program;
   * if not, write to the Free Software Foundation, Inc., 51
   * Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
   *
   * 2. For the Magnolia Network Agreement (MNA), this file
   * and the accompanying materials are made available under the
   * terms of the MNA which accompanies this distribution, and
   * is available at http://www.magnolia-cms.com/mna.html
   *
   * Any modifications to this file must keep this entire header
   * intact.
   *
   */
  package info.magnolia.module.mail.smtp.authentication;
  
  import info.magnolia.keystore.registry.PasswordRegistry;
  
  import java.io.IOException;
  
  import javax.inject.Inject;
  import javax.mail.Authenticator;
  import javax.mail.PasswordAuthentication;
  
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  import com.google.api.client.auth.oauth2.TokenErrorResponse;
  import com.google.api.client.auth.oauth2.TokenResponse;
  import com.google.api.client.auth.oauth2.TokenResponseException;
  import com.google.api.client.googleapis.auth.oauth2.GoogleRefreshTokenRequest;
  import com.google.api.client.http.javanet.NetHttpTransport;
  import com.google.api.client.json.jackson2.JacksonFactory;
  
  /**
   * Oauth2 SMTP authentication.
   */
  public class GoogleOauthSmtpAuthentication implements SmtpAuthentication {
  
      private static final Logger log = LoggerFactory.getLogger(GoogleOauthSmtpAuthentication.class);
  
      private String user;
      private String clientId;
      private String refreshTokenKeyStoreId;
      private String clientSecretKeyStoreId;
  
      private final PasswordRegistry passwordRegistry;
  
  
      @Inject
      public GoogleOauthSmtpAuthentication(PasswordRegistry passwordRegistry) {
          this.passwordRegistry = passwordRegistry;
      }
  
      public Authenticator getAuthenticator() {
          return new Authenticator() {
              @Override
              protected PasswordAuthentication getPasswordAuthentication() {
                  return new PasswordAuthentication(getUser(), getAccessToken());
              }
          };
      }
  
      /**
       * Obtain new access token from the refresh token & client credentials.
       */
      private String getAccessToken() {
          try {
              final TokenResponse response = new GoogleRefreshTokenRequest(new NetHttpTransport(), new JacksonFactory(), passwordRegistry.getPassword(getRefreshTokenKeyStoreId()).getDecryptedValue(), getClientId(), passwordRegistry.getPassword(getClientSecretKeyStoreId()).getDecryptedValue()).execute();
              return response.getAccessToken();
          } catch (IOException e) {
              log.debug("Error while requesting the access token.", e);
              if (e instanceof TokenResponseException) {
                  TokenErrorResponse details = ((TokenResponseException) e).getDetails();
                  if (details != null) {
                      log.debug(details.getError());
                  }
              }
              throw new RuntimeException(e);
          }
     }
 
     @Override
     public String getUser() {
         return user;
     }
 
     public void setUser(String user) {
         this.user = user;
     }
 
     public String getClientId() {
         return clientId;
     }
 
     public void setClientId(String clientId) {
         this.clientId = clientId;
     }
 
     public String getRefreshTokenKeyStoreId() {
         return refreshTokenKeyStoreId;
     }
 
     public void setRefreshTokenKeyStoreId(String refreshTokenKeyStoreId) {
         this.refreshTokenKeyStoreId = refreshTokenKeyStoreId;
     }
 
     public String getClientSecretKeyStoreId() {
         return clientSecretKeyStoreId;
     }
 
     public void setClientSecretKeyStoreId(String clientSecretKeyStoreId) {
         this.clientSecretKeyStoreId = clientSecretKeyStoreId;
     }
 }