/*
    *  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.directory.server.kerberos.changepwd.messages;
  
  
  import java.nio.ByteBuffer;
  
  import org.apache.directory.api.asn1.DecoderException;
  import org.apache.directory.api.asn1.EncoderException;
  import org.apache.directory.api.asn1.ber.Asn1Decoder;
  import org.apache.directory.api.util.Strings;
  import org.apache.directory.server.kerberos.changepwd.exceptions.ChangePasswdErrorType;
  import org.apache.directory.server.kerberos.changepwd.exceptions.ChangePasswordException;
  import org.apache.directory.shared.kerberos.codec.krbError.KrbErrorContainer;
  import org.apache.directory.shared.kerberos.messages.KrbError;
  
  
  /**
   * 
   * @author <a href="mailto:dev@directory.apache.org">Apache Directory Project</a>
   */
  public class ChangePasswordError extends AbstractPasswordMessage
  {
      private KrbError krbError;
  
      private short krbErrorLen;
      private short messageLength;
  
      public ChangePasswordError( KrbError krbError )
      {
          this( PVNO, krbError );
      }
      
      /**
       * Creates a new instance of ChangePasswordError.
       *
       * @param versionNumber The version number 
       * @param krbError The KRB-ERROR
       */
      public ChangePasswordError( short versionNumber, KrbError krbError )
      {
          super( versionNumber );
  
          this.krbError = krbError;
      }
  
  
      /**
       * Returns the {@link KrbError}.
       *
       * @return The {@link KrbError}.
       */
      public KrbError getKrbError()
      {
          return krbError;
      }
  
  
      @Override
      public short computeLength()
      {
          krbErrorLen = ( short ) krbError.computeLength();
          messageLength = ( short ) ( HEADER_LENGTH + krbErrorLen );
          
          return messageLength;
      }
  
      @Override
      public ByteBuffer encode( ByteBuffer buf ) throws EncoderException
      {
          buf.putShort( messageLength );
  
          buf.putShort( getVersionNumber() );
  
          buf.putShort( ( short )0 ); // zero means, what follows is an error
  
          krbError.encode( buf );
          
          return buf;
      }
  
      /**
      * Decodes a {@link ByteBuffer} into a {@link ChangePasswordError}.
      *
      * @param buf The buffer containing the ChangePasswordError to decode
      * @return The {@link ChangePasswordError}.
      * @throws ChangePasswordException If the decoding failed
      */
     public static ChangePasswordError decode( ByteBuffer buf ) throws ChangePasswordException
     {
         short messageLength = buf.getShort();
 
         short pvno = buf.getShort();
 
         // AP_REQ length will be 0 for error messages
         buf.getShort(); // authHeader length
 
         int errorLength = messageLength - HEADER_LENGTH;
 
         byte[] errorBytes = new byte[errorLength];
 
         buf.get( errorBytes );
         ByteBuffer errorBuffer = ByteBuffer.wrap( errorBytes );
 
         KrbErrorContainerros/codec/krbError/KrbErrorContainer.html#KrbErrorContainer">KrbErrorContainer container = new KrbErrorContainer( errorBuffer );
 
         try
         {
             Asn1Decoder.decode( errorBuffer, container );
         }
         catch( DecoderException e )
         {
             throw new ChangePasswordException( ChangePasswdErrorType.KRB5_KPASSWD_MALFORMED, e );
         }
         
         KrbError errorMessage = container.getKrbError();
 
         return new ChangePasswordError( pvno, errorMessage );
     }
 
     public ChangePasswdErrorType getResultCode()
     {
         ByteBuffer buf = ByteBuffer.wrap( krbError.getEData() );
         
         return ChangePasswdErrorType.getTypeByValue( buf.getShort() );
     }
     
     public String getResultString()
     {
         byte[] edata = krbError.getEData();
 
         // first two bytes contain the result code
         return Strings.utf8ToString( edata, 2, edata.length - 2 );
     }
 }