/*
    *   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.Checksum;
  import org.apache.directory.shared.kerberos.components.KrbSafeBody;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  
  /**
   * Class representing KRB-SAFE message
   * 
   * <pre>
   * KRB-SAFE        ::= [APPLICATION 20] SEQUENCE {
   *      pvno            [0] INTEGER (5),
   *      msg-type        [1] INTEGER (20),
   *      safe-body       [2] KRB-SAFE-BODY,
   *      cksum           [3] Checksum
   * }
   * </pre>
   * @author <a href="mailto:dev@directory.apache.org">Apache Directory Project</a>
   */
  public class KrbSafe extends KerberosMessage
  {
      /** The logger */
      private static final Logger log = LoggerFactory.getLogger( KrbError.class );
  
      /** Speedup for logs */
      private static final boolean IS_DEBUG = log.isDebugEnabled();
  
      /** body of this message */
      private KrbSafeBody krbSafeBody;
  
      /** the checksum */
      private Checksum checksum;
  
      // Storage for computed lengths
      private int pvnoLen;
      private int msgTypeLength;
      private int krbSafeBodyLen;
      private int checksumLen;
      private int krbSafeSeqLen;
      private int krbSafeLen;
  
  
      /**
       * Creates a new instance of KrbSafe.
       */
      public KrbSafe()
      {
          super( KerberosMessageType.KRB_SAFE );
      }
  
  
      /**
       * @return the krbSafeBody
       */
      public KrbSafeBody getSafeBody()
      {
          return krbSafeBody;
      }
  
  
      /**
       * @param safeBody the KrbSafeBody to set
       */
      public void setSafeBody( KrbSafeBody safeBody )
      {
         this.krbSafeBody = safeBody;
     }
 
 
     /**
      * @return the checksum
      */
     public Checksum getChecksum()
     {
         return checksum;
     }
 
 
     /**
      * @param checksum the checksum to set
      */
     public void setChecksum( Checksum checksum )
     {
         this.checksum = checksum;
     }
 
 
     /**
      * Compute the KRB-SAFE length
      * <pre>
      * KRB-SAFE :
      * 
      * 0x74 L1 KRB-SAFE APPLICATION[20]
      *  |
      *  +--&gt; 0x30 L2 KRB-ERROR sequence
      *        |
      *        +--&gt; 0xA0 0x03 pvno tag
      *        |     |
      *        |     +--&gt; 0x02 0x01 0x05 pvno (5)
      *        |
      *        +--&gt; 0xA1 0x03 msg-type tag
      *        |     |
      *        |     +--&gt; 0x02 0x01 0x14 msg-type (20)
      *        |     
      *        +--&gt; 0xA2 L3 safe-body tag
      *        |     |
      *        |     +--&gt; 0x30 L3-1 safe-body (KRB-SAFE-BODY)
      *        |
      *        +--&gt; 0xA3 L4 cksum tag
      *              |
      *              +--&gt; 0x30 L4-1 cksum (CHECKSUM)
      * </pre>
      */
     @Override
     public int computeLength()
     {
         pvnoLen = 1 + 1 + 1;
         krbSafeSeqLen = 1 + TLV.getNbBytes( pvnoLen ) + pvnoLen;
 
         msgTypeLength = 1 + 1 + BerValue.getNbBytes( getMessageType().getValue() );
         krbSafeSeqLen += 1 + TLV.getNbBytes( msgTypeLength ) + msgTypeLength;
 
         krbSafeBodyLen = krbSafeBody.computeLength();
         krbSafeSeqLen += 1 + TLV.getNbBytes( krbSafeBodyLen ) + krbSafeBodyLen;
 
         checksumLen = checksum.computeLength();
         krbSafeSeqLen += 1 + TLV.getNbBytes( checksumLen ) + checksumLen;
 
         krbSafeLen = 1 + TLV.getNbBytes( krbSafeSeqLen ) + krbSafeSeqLen;
 
         return 1 + TLV.getNbBytes( krbSafeLen ) + krbSafeLen;
     }
 
 
     /**
      * {@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_SAFE_TAG );
             buffer.put( TLV.getBytes( krbSafeLen ) );
 
             // The KRB-SAFE sequence
             buffer.put( UniversalTag.SEQUENCE.getValue() );
             buffer.put( TLV.getBytes( krbSafeSeqLen ) );
 
             // pvno tag and value
             buffer.put( ( byte ) KerberosConstants.KRB_SAFE_PVNO_TAG );
             buffer.put( TLV.getBytes( pvnoLen ) );
             BerValue.encode( buffer, getProtocolVersionNumber() );
 
             // msg-type tag and value
             buffer.put( ( byte ) KerberosConstants.KRB_SAFE_MSGTYPE_TAG );
             buffer.put( TLV.getBytes( msgTypeLength ) );
             BerValue.encode( buffer, getMessageType().getValue() );
 
             // safe-body tag and value
             buffer.put( ( byte ) KerberosConstants.KRB_SAFE_SAFE_BODY_TAG );
             buffer.put( TLV.getBytes( krbSafeBodyLen ) );
             krbSafeBody.encode( buffer );
 
             // cksum tag and value
             buffer.put( ( byte ) KerberosConstants.KRB_SAFE_CKSUM_TAG );
             buffer.put( TLV.getBytes( checksumLen ) );
             checksum.encode( buffer );
         }
         catch ( BufferOverflowException boe )
         {
             log.error( I18n.err( I18n.ERR_736_CANNOT_ENCODE_KRBSAFE, 1 + TLV.getNbBytes( krbSafeLen )
                 + krbSafeLen, buffer.capacity() ) );
             throw new EncoderException( I18n.err( I18n.ERR_138 ), boe );
         }
 
         if ( IS_DEBUG )
         {
             log.debug( "KrbSafe encoding : {}", Strings.dumpBytes( buffer.array() ) );
             log.debug( "KrbSafe initial value : {}", this );
         }
 
         return buffer;
     }
 
 
     /**
      * @see Object#toString()
      */
     public String toString()
     {
         StringBuilder sb = new StringBuilder();
 
         sb.append( "KRB-SAFE : {\n" );
         sb.append( "    pvno: " ).append( getProtocolVersionNumber() ).append( '\n' );
         sb.append( "    msgType: " ).append( getMessageType() ).append( '\n' );
 
         if ( krbSafeBody != null )
         {
             sb.append( "    safe-body: " ).append( krbSafeBody ).append( '\n' );
         }
 
         if ( checksum != null )
         {
             sb.append( "    cusec: " ).append( checksum ).append( '\n' );
         }
 
         sb.append( "}\n" );
 
         return sb.toString();
     }
 }