/*
    *  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.codec.controls.proxiedauthz;
  
  
  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.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.model.message.controls.ProxiedAuthz;
  import org.apache.directory.api.ldap.model.message.controls.ProxiedAuthzImpl;
  import org.apache.directory.api.util.Strings;
  
  
  /**
   * An ProxiedAuthz implementation, that wraps and decorates the Control with codec
   * specific functionality.
   *
   *
   * @author <a href="mailto:dev@directory.apache.org">Apache Directory Project</a>
   */
  public class ProxiedAuthzDecorator extends ControlDecorator<ProxiedAuthz> implements ProxiedAuthz
  {
      /** A temporary storage for the authzId */
      private byte[] authzIdBytes = null;
  
      /** An instance of this decoder */
      private static final Asn1Decoder decoder = new Asn1Decoder();
  
  
      /**
       * Creates a new instance of ProxiedAuthzDecoder wrapping a newly created
       * ProxiedAuthz Control object.
       */
      public ProxiedAuthzDecorator( LdapApiService codec )
      {
          super( codec, new ProxiedAuthzImpl() );
      }
  
  
      /**
       * Creates a new instance of ProxiedAuthzDecorator wrapping the supplied
       * ProxiedAuthz Control.
       *
       * @param control The ProxiedAuthz Control to be decorated.
       */
      public ProxiedAuthzDecorator( LdapApiService codec, ProxiedAuthz control )
      {
          super( codec, control );
      }
  
  
      /**
       * Internally used to not have to cast the decorated Control.
       *
       * @return the decorated Control.
       */
      private ProxiedAuthz getProxiedAuthz()
      {
          return ( ProxiedAuthz ) getDecorated();
      }
  
  
      /**
       * Compute the ProxiedAuthzControl length 
       * 
       *  0x04 L1 authzId] 
       */
      public int computeLength()
      {
          int valueLength = 0;
  
          if ( getAuthzId() != null )
          {
              authzIdBytes = Strings.getBytesUtf8( getAuthzId() );
              valueLength = authzIdBytes.length;
         }
 
         return valueLength;
     }
 
 
     /**
      * Encodes the ProxiedAuthz control.
      * 
      * @param buffer The encoded sink
      * @return A ByteBuffer that contains the encoded PDU
      * @throws EncoderException If anything goes wrong.
      */
     public ByteBuffer encode( ByteBuffer buffer ) throws EncoderException
     {
         if ( buffer == null )
         {
             throw new EncoderException( I18n.err( I18n.ERR_04023 ) );
         }
 
         if ( getAuthzId() != null )
         {
             buffer.put( authzIdBytes );
         }
 
         return buffer;
     }
 
 
     /**
      * {@inheritDoc}
      */
     public byte[] getValue()
     {
         if ( value == null )
         {
             try
             {
                 computeLength();
                 ByteBuffer buffer = ByteBuffer.allocate( valueLength );
 
                 if ( authzIdBytes != null )
                 {
                     BerValue.encode( buffer, authzIdBytes );
                 }
                 else
                 {
                     BerValue.encode( buffer, Strings.EMPTY_BYTES );
                 }
 
                 value = buffer.array();
             }
             catch ( Exception e )
             {
                 return null;
             }
         }
 
         return value;
     }
 
 
     /**
      * {@inheritDoc}
      */
     public String getAuthzId()
     {
         return getProxiedAuthz().getAuthzId();
     }
 
 
     /**
      * {@inheritDoc}
      */
     public void setAuthzId( String authzId )
     {
         getProxiedAuthz().setAuthzId( authzId );
     }
 
 
     /**
      * {@inheritDoc}
      */
     public Asn1Object decode( byte[] controlBytes ) throws DecoderException
     {
         getProxiedAuthz().setAuthzId( Strings.utf8ToString( controlBytes ) );
 
         return this;
     }
 }