content: /*
   * LunaticSMTP
   * Copyright (C) 2016  Anton Larionov
   *
   * This program is free software: you can redistribute it and/or modify
   * it under the terms of the GNU General Public License as published by
   * the Free Software Foundation, either version 3 of the License, or
   * (at your option) any later version.
   *
   * This program is distributed in the hope that it will be useful,
   * but WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   * GNU General Public License for more details.
   *
   * You should have received a copy of the GNU General Public License
   * along with this program.  If not, see <http://www.gnu.org/licenses/>.
   */
  
  package com.gitlab.anlar.lunatic.server.auth;
  
  import org.subethamail.smtp.AuthenticationHandler;
  
  public class SMTPAuthHandler implements AuthenticationHandler {
      private static final String USER_IDENTITY = "User";
      private static final String PROMPT_USERNAME = "334 VXNlcm5hbWU6"; // VXNlcm5hbWU6 is base64 for "Username:"
      private static final String PROMPT_PASSWORD = "334 UGFzc3dvcmQ6"; // UGFzc3dvcmQ6 is base64 for "Password:"
  
      private int pass = 0;
  
      @Override
      public String auth(String clientInput) {
          String prompt;
  
          if (++pass == 1) {
              prompt = SMTPAuthHandler.PROMPT_USERNAME;
          } else if (pass == 2) {
              prompt = SMTPAuthHandler.PROMPT_PASSWORD;
          } else {
              pass = 0;
              prompt = null;
          }
          return prompt;
      }
  
      @Override
      public Object getIdentity() {
          return SMTPAuthHandler.USER_IDENTITY;
      }
  }
  