/*
    *  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.components;
  
  
  import java.nio.BufferOverflowException;
  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.server.i18n.I18n;
  import org.apache.directory.shared.kerberos.KerberosConstants;
  import org.apache.directory.shared.kerberos.codec.types.PaDataType;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  
  /**
   * The Pre-Authentication data. The ASN.1 GRAMMAR IS :
   * <pre>
   * PA-DATA         ::= SEQUENCE {
   *         -- NOTE: first tag is [1], not [0]
   *         padata-type     [1] Int32,
   *         padata-value    [2] OCTET STRING -- might be encoded AP-REQ
   * }
   * </pre>
   * @author <a href="mailto:dev@directory.apache.org">Apache Directory Project</a>
   */
  public class PaData implements Asn1Object
  {
      /** The logger */
      private static final Logger log = LoggerFactory.getLogger( PaData.class );
  
      /** Speedup for logs */
      private static final boolean IS_DEBUG = log.isDebugEnabled();
  
      /** The Pre-authentication type */
      private PaDataType paDataType;
  
      /** The authentication data */
      private byte[] paDataValue;
  
      // Storage for computed lengths
      private int paDataTypeTagLength;
      private int paDataValueTagLength;
      private int preAuthenticationDataSeqLength;
  
  
      /**
       * Creates a new instance of PreAuthenticationData.
       */
      public PaData()
      {
      }
  
  
      /**
       * Creates a new instance of PreAuthenticationData.
       *
       * @param paDataType
       * @param paDataValue
       */
      public PaData( PaDataType paDataType, byte[] paDataValue )
      {
          this.paDataType = paDataType;
          this.paDataValue = paDataValue;
      }
  
  
      /**
       * Returns the {@link PaDataType}.
       *
       * @return The {@link PaDataType}.
       */
      public PaDataType getPaDataType()
      {
          return paDataType;
      }
 
 
     /**
      * Set the PA-DATA type
      *
      * @param paDataType The PA-DATA type
      */
     public void setPaDataType( int paDataType )
     {
         this.paDataType = PaDataType.getTypeByValue( paDataType );
     }
 
 
     /**
      * Set the PA-DATA type
      *
      * @param paDataType The PA-DATA type
      */
     public void setPaDataType( PaDataType paDataType )
     {
         this.paDataType = paDataType;
     }
 
 
     /**
      * Returns the raw bytes of the {@link PaData}.
      *
      * @return The raw bytes of the {@link PaData}.
      */
     public byte[] getPaDataValue()
     {
         return paDataValue;
     }
 
 
     /**
      * Set the PA-DATA value
      *
      * @param paDataValue The PA-DATA value
      */
     public void setPaDataValue( byte[] paDataValue )
     {
         this.paDataValue = paDataValue;
     }
 
 
     /**
      * Compute the PreAuthenticationData length
      * <pre>
      * PreAuthenticationData :
      * 
      * 0x30 L1 PreAuthenticationData sequence
      *  |
      *  +--&gt; 0xA0 L2 padata-type tag
      *  |     |
      *  |     +--&gt; 0x02 L2-1 padata-type (int)
      *  |
      *  +--&gt; 0xA1 L3 padata-value tag
      *        |
      *        +--&gt; 0x04 L3-1 padata-value (OCTET STRING)
      *        
      *  where L1 = L2 + lenght(0xA0) + length(L2) +
      *             L3 + lenght(0xA1) + length(L3) 
      *  and
      *  L2 = L2-1 + length(0x02) + length( L2-1) 
      *  L3 = L3-1 + length(0x04) + length( L3-1) 
      *  </pre>
      */
     public int computeLength()
     {
         // Compute the paDataType. The Length will always be contained in 1 byte
         int paDataTypeLength = BerValue.getNbBytes( paDataType.getValue() );
         paDataTypeTagLength = 1 + TLV.getNbBytes( paDataTypeLength ) + paDataTypeLength;
         preAuthenticationDataSeqLength = 1 + TLV.getNbBytes( paDataTypeTagLength ) + paDataTypeTagLength;
 
         // Compute the paDataValue
         if ( paDataValue == null )
         {
             paDataValueTagLength = 1 + 1;
         }
         else
         {
             paDataValueTagLength = 1 + TLV.getNbBytes( paDataValue.length ) + paDataValue.length;
         }
 
         // Compute the whole sequence length
         preAuthenticationDataSeqLength += 1 + TLV.getNbBytes( paDataValueTagLength ) + paDataValueTagLength;
 
         return 1 + TLV.getNbBytes( preAuthenticationDataSeqLength ) + preAuthenticationDataSeqLength;
 
     }
 
 
     /**
      * Encode the PreAuthenticationData message to a PDU. 
      * <pre>
      * PreAuthenticationData :
      * 
      * 0x30 LL
      *   0xA1 LL 
      *     0x02 0x01 padata-type
      *   0xA2 LL 
      *     0x04 LL padata-value
      * </pre>
      * @param buffer The buffer where to put the PDU. It should have been allocated
      * before, with the right size.
      * @return The constructed PDU.
      */
     public ByteBuffer encode( ByteBuffer buffer ) throws EncoderException
     {
         if ( buffer == null )
         {
             throw new EncoderException( I18n.err( I18n.ERR_148 ) );
         }
 
         try
         {
             // The PreAuthenticationData SEQ Tag
             buffer.put( UniversalTag.SEQUENCE.getValue() );
             buffer.put( TLV.getBytes( preAuthenticationDataSeqLength ) );
 
             // The PaDataType, first the tag, then the value
             buffer.put( ( byte ) KerberosConstants.PADATA_TYPE_TAG );
             buffer.put( TLV.getBytes( paDataTypeTagLength ) );
             BerValue.encode( buffer, paDataType.getValue() );
 
             // The PaDataValue, first the tag, then the value
             buffer.put( ( byte ) KerberosConstants.PADATA_VALUE_TAG );
             buffer.put( TLV.getBytes( paDataValueTagLength ) );
             BerValue.encode( buffer, paDataValue );
         }
         catch ( BufferOverflowException boe )
         {
             log.error( I18n.err( I18n.ERR_145, 1 + TLV.getNbBytes( preAuthenticationDataSeqLength )
                 + preAuthenticationDataSeqLength, buffer.capacity() ) );
             throw new EncoderException( I18n.err( I18n.ERR_138 ), boe );
         }
 
         if ( IS_DEBUG )
         {
             log.debug( "PreAuthenticationData encoding : {}", Strings.dumpBytes( buffer.array() ) );
             log.debug( "PreAuthenticationData initial value : {}", this );
         }
 
         return buffer;
     }
 
 
     /**
      * @see Object#toString()
      */
     public String toString()
     {
         return toString( "" );
     }
 
 
     /**
      * @see Object#toString()
      */
     public String toString( String tabs )
     {
         StringBuilder sb = new StringBuilder();
 
         sb.append( tabs ).append( "PreAuthenticationData : \n" );
         sb.append( tabs ).append( "    padata-type: " ).append( paDataType ).append( '\n' );
 
         if ( paDataValue != null )
         {
             sb.append( tabs + "    padata-value:" ).append( Strings.dumpBytes( paDataValue ) ).append( '\n' );
         }
 
         return sb.toString();
     }
 }