/*
    *   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.api.ldap.extras.controls.vlv_impl;
  
  
  import java.nio.ByteBuffer;
  
  import org.apache.directory.api.asn1.Asn1Object;
  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.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.i18n.I18n;
  import org.apache.directory.api.ldap.codec.api.ControlDecorator;
  import org.apache.directory.api.ldap.codec.api.LdapApiService;
  import org.apache.directory.api.ldap.extras.controls.vlv.VirtualListViewResponse;
  import org.apache.directory.api.ldap.extras.controls.vlv.VirtualListViewResponseImpl;
  import org.apache.directory.api.ldap.extras.controls.vlv.VirtualListViewResultCode;
  
  
  /**
   * The VirtualListView response decorator
   *
   * @author <a href="mailto:dev@directory.apache.org">Apache Directory Project</a>
   */
  public class VirtualListViewResponseDecorator extends ControlDecorator<VirtualListViewResponse> implements
      VirtualListViewResponse
  {
      private int vlvSeqLength;
  
      private static final Asn1Decoder decoder = new Asn1Decoder();
  
  
      public VirtualListViewResponseDecorator( LdapApiService codec )
      {
          this( codec, new VirtualListViewResponseImpl() );
      }
  
  
      public VirtualListViewResponseDecorator( LdapApiService codec, VirtualListViewResponse vlvRequest )
      {
          super( codec, vlvRequest );
      }
  
  
      /**
       * {@inheritDoc}
       */
      public int computeLength()
      {
          vlvSeqLength = 1 + 1 + BerValue.getNbBytes( getTargetPosition() );
          vlvSeqLength += 1 + 1 + BerValue.getNbBytes( getContentCount() );
  
          // result code : always one byte long
          vlvSeqLength += 1 + 1 + 1;
  
          if ( getContextId() != null )
          {
              vlvSeqLength += 1 + TLV.getNbBytes( getContextId().length ) + getContextId().length;
          }
  
          valueLength = 1 + TLV.getNbBytes( vlvSeqLength ) + vlvSeqLength;
  
          return valueLength;
      }
  
  
      /**
       * {@inheritDoc}
       */
      public ByteBuffer encode( ByteBuffer buffer ) throws EncoderException
      {
          if ( buffer == null )
          {
              throw new EncoderException( I18n.err( I18n.ERR_04023 ) );
          }
  
          buffer.put( UniversalTag.SEQUENCE.getValue() );
          buffer.put( TLV.getBytes( vlvSeqLength ) );
 
         BerValue.encode( buffer, getTargetPosition() );
         BerValue.encode( buffer, getContentCount() );
 
         BerValue.encodeEnumerated( buffer, getVirtualListViewResult().getVal() );
 
         if ( getContextId() != null )
         {
             BerValue.encode( buffer, getContextId() );
         }
 
         return buffer;
     }
 
 
     /**
      * {@inheritDoc}
      */
     public byte[] getValue()
     {
         if ( value == null )
         {
             try
             {
                 computeLength();
                 ByteBuffer buffer = ByteBuffer.allocate( valueLength );
 
                 value = encode( buffer ).array();
             }
             catch ( Exception e )
             {
                 return null;
             }
         }
 
         return value;
     }
 
 
     /**
      * {@inheritDoc}
      */
     @Override
     public Asn1Object decode( byte[] controlBytes ) throws DecoderException
     {
         ByteBuffer buffer = ByteBuffer.wrap( controlBytes );
         VirtualListViewResponseContainer container = new VirtualListViewResponseContainer( this, getCodecService() );
         decoder.decode( buffer, container );
 
         return this;
     }
 
 
     /**
      * {@inheritDoc}
      */
     @Override
     public int getTargetPosition()
     {
         return getDecorated().getTargetPosition();
     }
 
 
     /**
      * {@inheritDoc}
      */
     @Override
     public void setTargetPosition( int targetPosition )
     {
         getDecorated().setTargetPosition( targetPosition );
     }
 
 
     /**
      * {@inheritDoc}
      */
     @Override
     public int getContentCount()
     {
         return getDecorated().getContentCount();
     }
 
 
     /**
      * {@inheritDoc}
      */
     @Override
     public void setContentCount( int contentCount )
     {
         getDecorated().setContentCount( contentCount );
     }
 
 
     /**
      * {@inheritDoc}
      */
     @Override
     public VirtualListViewResultCode getVirtualListViewResult()
     {
         return getDecorated().getVirtualListViewResult();
     }
 
 
     /**
      * {@inheritDoc}
      */
     @Override
     public void setVirtualListViewResult( VirtualListViewResultCode virtualListViewResult )
     {
         getDecorated().setVirtualListViewResult( virtualListViewResult );
     }
 
 
     /**
      * {@inheritDoc}
      */
     @Override
     public byte[] getContextId()
     {
         return getDecorated().getContextId();
     }
 
 
     /**
      * {@inheritDoc}
      */
     @Override
     public void setContextId( byte[] contextId )
     {
         getDecorated().setContextId( contextId );
     }
 
 }