/*
 * 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.activemq.transport.amqp.client.sasl;

/**
 * Implements the SASL PLAIN authentication Mechanism.
 * <p>
 * User name and Password values are sent without being encrypted.
 */
public class PlainMechanism extends AbstractMechanism {

   public static final String MECH_NAME = "PLAIN";

   @Override
   public int getPriority() {
      return PRIORITY.MEDIUM.getValue();
   }

   @Override
   public String getName() {
      return MECH_NAME;
   }

   @Override
   public byte[] getInitialResponse() {

      String authzid = getAuthzid();
      String username = getUsername();
      String password = getPassword();

      if (authzid == null) {
         authzid = "";
      }

      if (username == null) {
         username = "";
      }

      if (password == null) {
         password = "";
      }

      byte[] authzidBytes = authzid.getBytes();
      byte[] usernameBytes = username.getBytes();
      byte[] passwordBytes = password.getBytes();
      byte[] data = new byte[authzidBytes.length + 1 + usernameBytes.length + 1 + passwordBytes.length];
      System.arraycopy(authzidBytes, 0, data, 0, authzidBytes.length);
      System.arraycopy(usernameBytes, 0, data, 1 + authzidBytes.length, usernameBytes.length);
      System.arraycopy(passwordBytes, 0, data, 2 + authzidBytes.length + usernameBytes.length, passwordBytes.length);
      return data;
   }

   @Override
   public byte[] getChallengeResponse(byte[] challenge) {
      return EMPTY;
   }

   @Override
   public boolean isApplicable(String username, String password) {
      return username != null && !username.isEmpty() && password != null && !password.isEmpty();
   }
}
