/*
    *  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.shared.kerberos.messages;
  
  
  import java.nio.ByteBuffer;
  
  import org.apache.directory.api.asn1.Asn1Object;
  import org.apache.directory.api.asn1.EncoderException;
  import org.apache.directory.api.asn1.ber.tlv.BerValue;
  import org.apache.directory.api.asn1.ber.tlv.TLV;
  import org.apache.directory.api.asn1.ber.tlv.UniversalTag;
  import org.apache.directory.api.util.Strings;
  import org.apache.directory.shared.kerberos.KerberosConstants;
  import org.apache.directory.shared.kerberos.components.PrincipalName;
  
  
  /**
   * Change password data structure
   * 
   * ChangePasswdData ::=  SEQUENCE {
   *       newpasswd[0]   OCTET STRING,
   *       targname[1]    PrincipalName OPTIONAL,
   *       targrealm[2]   Realm OPTIONAL
   *     }
   *     
   * @author <a href="mailto:dev@directory.apache.org">Apache Directory Project</a>
   */
  public class ChangePasswdData implements Asn1Object
  {
  
      /** the new password */
      private byte[] newPasswd;
  
      /** principal name of the client */
      private PrincipalName targName;
  
      /** name of client's realm */
      private String targRealm;
  
      private int newPasswdLen;
      private int targNameLen;
      private int targRealmLen;
      private int seqLen;
  
  
      public ChangePasswdData()
      {
      }
  
  
      /**
       * Compute the ChangePasswdData length
       * <pre>
       * ChangePasswdData :
       *
       * 0x30 L1 ChangePasswdData sequence
       *  |
       *  +--&gt; 0xA0 L2 newPasswd tag
       *  |     |
       *  |     +--&gt; 0x04 L2-1 newPasswd (Octet string)
       *  |
       *  +--&gt; 0xA1 L3 targName tag
       *  |     |
       *  |     +--&gt; 0x30 L3-1 targName (PrincipalName)
       *  |
       *  +--&gt; 0xA2 L4 targRealm tag
       *        |
       *        +--&gt; 0x1B L4-1 targRealm (KerberosString)
       * </pre>
       */
      @Override
      public int computeLength()
      {
          newPasswdLen = 1 + TLV.getNbBytes( newPasswd.length ) + newPasswd.length;
  
          seqLen = 1 + TLV.getNbBytes( newPasswdLen ) + newPasswdLen;
  
          if ( targName != null )
          {
              targNameLen = targName.computeLength();
              seqLen += 1 + TLV.getNbBytes( targNameLen ) + targNameLen;
         }
 
         if ( targRealm != null )
         {
             targRealmLen = Strings.getBytesUtf8( targRealm ).length;
             targRealmLen = 1 + TLV.getNbBytes( targRealmLen ) + targRealmLen;
             seqLen += 1 + TLV.getNbBytes( targRealmLen ) + targRealmLen;
         }
 
         return 1 + TLV.getNbBytes( seqLen ) + seqLen;
     }
 
 
     @Override
     public ByteBuffer encode( ByteBuffer buffer ) throws EncoderException
     {
         if ( buffer == null )
         {
             buffer = ByteBuffer.allocate( computeLength() );
         }
 
         // ChangePasswdData
         buffer.put( UniversalTag.SEQUENCE.getValue() );
         buffer.put( BerValue.getBytes( seqLen ) );
 
         // newpasswd
         buffer.put( ( byte ) KerberosConstants.CHNGPWD_NEWPWD_TAG );
         buffer.put( BerValue.getBytes( newPasswdLen ) );
         BerValue.encode( buffer, newPasswd );
 
         if ( targName != null )
         {
             buffer.put( ( byte ) KerberosConstants.CHNGPWD_TARGNAME_TAG );
             buffer.put( BerValue.getBytes( targNameLen ) );
 
             targName.encode( buffer );
         }
 
         if ( targRealm != null )
         {
             buffer.put( ( byte ) KerberosConstants.CHNGPWD_TARGREALM_TAG );
             buffer.put( BerValue.getBytes( targRealmLen ) );
             buffer.put( UniversalTag.GENERAL_STRING.getValue() );
             buffer.put( BerValue.getBytes( targRealmLen - 2 ) );
             buffer.put( Strings.getBytesUtf8( targRealm ) );
         }
 
         return buffer;
     }
 
 
     public byte[] getNewPasswd()
     {
         return newPasswd;
     }
 
 
     public void setNewPasswd( byte[] newPasswd )
     {
         this.newPasswd = newPasswd;
     }
 
 
     public PrincipalName getTargName()
     {
         return targName;
     }
 
 
     public void setTargName( PrincipalName targName )
     {
         this.targName = targName;
     }
 
 
     public String getTargRealm()
     {
         return targRealm;
     }
 
 
     public void setTargRealm( String targRealm )
     {
         this.targRealm = targRealm;
     }
 
 
     /**
      * @see Object#toString()
      */
     public String toString()
     {
         StringBuilder sb = new StringBuilder();
 
         sb.append( "ChangePasswdData : \n" );
 
         sb.append( "    newPasswd : " ).append( Strings.utf8ToString( newPasswd ) ).append( '\n' );
         sb.append( "    targName : " ).append( targName ).append( '\n' );
         sb.append( "    targRealm : " ).append( targRealm ).append( '\n' );
 
         return sb.toString();
     }
 }