/*
    *   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.BufferOverflowException;
  import java.nio.ByteBuffer;
  
  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.server.i18n.I18n;
  import org.apache.directory.shared.kerberos.KerberosConstants;
  import org.apache.directory.shared.kerberos.KerberosMessageType;
  import org.apache.directory.shared.kerberos.components.EncryptedData;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  
  /**
   * Class representing KRB-PRIV message
   * 
   * <pre>
   * KRB-PRIV        ::= [APPLICATION 21] SEQUENCE {
   *      pvno            [0] INTEGER (5),
   *      msg-type        [1] INTEGER (21),
   *                      -- NOTE: there is no [2] tag
   *      enc-part        [3] EncryptedData -- EncKrbPrivPart
   * }
   * </pre>
   * @author <a href="mailto:dev@directory.apache.org">Apache Directory Project</a>
   */
  public class KrbPriv extends KerberosMessage
  {
      /** The logger */
      private static final Logger log = LoggerFactory.getLogger( KrbError.class );
  
      /** Speedup for logs */
      private static final boolean IS_DEBUG = log.isDebugEnabled();
  
      /** the encrypted EncKrbPrivPart component */
      private EncryptedData encPart;
  
      // Storage for computed lengths
      private int pvnoLen;
      private int msgTypeLength;
      private int encPartLen;
      private int krbPrivSeqLen;
      private int krbPrivLen;
  
  
      /**
       * Creates a new instance of KrbPriv.
       */
      public KrbPriv()
      {
          super( 5, KerberosMessageType.KRB_PRIV );
      }
  
  
      /**
       * @return the encPart
       */
      public EncryptedData getEncPart()
      {
          return encPart;
      }
  
  
      /**
       * @param encPart the encPart to set
       */
      public void setEncPart( EncryptedData encPart )
      {
          this.encPart = encPart;
      }
  
  
      /**
      * Compute the KRB-PRIV length
      * <pre>
      * KRB-PRIV :
      * 
      * 0x75 L1 KRB-PRIV APPLICATION[21]
      *  |
      *  +--&gt; 0x30 L2 KRB-PRIV sequence
      *        |
      *        +--&gt; 0xA0 0x03 pvno tag
      *        |     |
      *        |     +--&gt; 0x02 0x01 0x05 pvno (5)
      *        |
      *        +--&gt; 0xA1 0x03 msg-type tag
      *        |     |
      *        |     +--&gt; 0x02 0x01 0x15 msg-type (21)
      *        |     
      *        +--&gt; 0xA3 L3 enc-part (EncryptedData -- EncKrbPrivPart)
      * </pre>
      */
     @Override
     public int computeLength()
     {
         pvnoLen = 1 + 1 + 1;
         krbPrivSeqLen = 1 + TLV.getNbBytes( pvnoLen ) + pvnoLen;
 
         msgTypeLength = 1 + 1 + BerValue.getNbBytes( getMessageType().getValue() );
         krbPrivSeqLen += 1 + TLV.getNbBytes( msgTypeLength ) + msgTypeLength;
 
         encPartLen = encPart.computeLength();
         krbPrivSeqLen += 1 + TLV.getNbBytes( encPartLen ) + encPartLen;
 
         krbPrivLen += 1 + TLV.getNbBytes( krbPrivSeqLen ) + krbPrivSeqLen;
 
         return 1 + TLV.getNbBytes( krbPrivLen ) + krbPrivLen;
     }
 
 
     /**
      * {@inheritDoc}
      */
     @Override
     public ByteBuffer encode( ByteBuffer buffer ) throws EncoderException
     {
         if ( buffer == null )
         {
             throw new EncoderException( I18n.err( I18n.ERR_148 ) );
         }
 
         try
         {
             // The KRB-SAFE APPLICATION tag
             buffer.put( ( byte ) KerberosConstants.KRB_PRIV_TAG );
             buffer.put( TLV.getBytes( krbPrivLen ) );
 
             // The KRB-SAFE sequence
             buffer.put( UniversalTag.SEQUENCE.getValue() );
             buffer.put( TLV.getBytes( krbPrivSeqLen ) );
 
             // pvno tag and value
             buffer.put( ( byte ) KerberosConstants.KRB_PRIV_PVNO_TAG );
             buffer.put( TLV.getBytes( pvnoLen ) );
             BerValue.encode( buffer, getProtocolVersionNumber() );
 
             // msg-type tag and value
             buffer.put( ( byte ) KerberosConstants.KRB_PRIV_MSGTYPE_TAG );
             buffer.put( TLV.getBytes( msgTypeLength ) );
             BerValue.encode( buffer, getMessageType().getValue() );
 
             // enc-part
             buffer.put( ( byte ) KerberosConstants.KRB_PRIV_ENC_PART_TAG );
             buffer.put( TLV.getBytes( encPartLen ) );
             encPart.encode( buffer );
         }
         catch ( BufferOverflowException boe )
         {
             log.error( I18n.err( I18n.ERR_738_CANNOT_ENCODE_KRB_PRIV, 1 + TLV.getNbBytes( krbPrivLen )
                 + krbPrivLen, buffer.capacity() ) );
             throw new EncoderException( I18n.err( I18n.ERR_138 ), boe );
         }
 
         if ( IS_DEBUG )
         {
             log.debug( "KrbPriv encoding : {}", Strings.dumpBytes( buffer.array() ) );
             log.debug( "KrbPriv initial value : {}", this );
         }
 
         return buffer;
     }
 
 
     /**
      * @see Object#toString()
      */
     public String toString()
     {
         StringBuilder sb = new StringBuilder();
 
         sb.append( "KRB-PRIV : {\n" );
         sb.append( "    pvno: " ).append( getProtocolVersionNumber() ).append( '\n' );
         sb.append( "    msgType: " ).append( getMessageType() ).append( '\n' );
         sb.append( "    msgType: " ).append( getEncPart() ).append( '\n' );
         sb.append( "}\n" );
 
         return sb.toString();
     }
 }