/*
    *  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.KerberosTime;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  
  /**
   * The PaEncTsEnc structure is used to store a PA-ENC-TS-ENC associated to a type.
   * 
   * The ASN.1 grammar is :
   * <pre>
   * PA-ENC-TS-ENC           ::= SEQUENCE {
   *         patimestamp     [0] KerberosTime -- client's time --,
   *         pausec          [1] Microseconds OPTIONAL
   * }
   * </pre>
   * @author <a href="mailto:dev@directory.apache.org">Apache Directory Project</a>
   */
  public class PaEncTsEnc implements Asn1Object
  {
      /** The logger */
      private static final Logger log = LoggerFactory.getLogger( PaEncTsEnc.class );
  
      /** Speedup for logs */
      private static final boolean IS_DEBUG = log.isDebugEnabled();
  
      /** The patimestamp */
      private KerberosTime patimestamp;
  
      /** The pausec */
      private Integer pausec;
  
      // Storage for computed lengths
      private int paTimestampLength;
      private int paUsecLength;
      private int paEncTsEncLength;
  
  
      /**
       * Creates a new instance of PaEncTsEnc.
       */
      public PaEncTsEnc()
      {
      }
  
  
      /**
       * Creates a new instance of PaEncTsEnc.
       */
      public PaEncTsEnc( KerberosTime paTimestamp, int pausec )
      {
          this.patimestamp = paTimestamp;
          this.pausec = pausec;
      }
  
  
      /**
       * Returns the patimestamp value.
       *
       * @return The patimestamp value.
       */
      public KerberosTime getPaTimestamp()
      {
          return patimestamp;
      }
  
  
     /**
      * Set the patimestamp.
      *
      * @param patimestamp The patimestamp value
      */
     public void setPaTimestamp( KerberosTime patimestamp )
     {
         this.patimestamp = patimestamp;
     }
 
 
     /**
      * @return the pausec
      */
     public int getPausec()
     {
         if ( pausec == null )
         {
             return -1;
         }
 
         return pausec;
     }
 
 
     /**
      * @param pausec the pausec to set
      */
     public void setPausec( int pausec )
     {
         this.pausec = pausec;
     }
 
 
     /**
      * Compute the PA-ENC-TS-ENC length
      * <pre>
      * PA-ENC-TS-ENC :
      * 
      * 0x30 L1 PA-ENC-TS-ENC sequence
      *  |
      *  +--&gt; 0xA0 0x11 patimestamp tag
      *  |     |
      *  |     +--&gt; 0x18 0x0F patimestamp value (KerberosTime)
      *  |
      *  +--&gt; 0xA1 L2 pausec tag
      *        |
      *        +--&gt; 0x02 L2-1 pausec (INTEGER)
      *        
      *  </pre>
      */
     public int computeLength()
     {
         // The paTimestamp
         paTimestampLength = 0x11;
 
         paEncTsEncLength = 1 + TLV.getNbBytes( paTimestampLength ) + paTimestampLength;
 
         // The pausec, if any
         if ( pausec != null )
         {
             int pausecLength = BerValue.getNbBytes( pausec );
             paUsecLength = 1 + TLV.getNbBytes( pausecLength ) + pausecLength;
             paEncTsEncLength += 1 + TLV.getNbBytes( paUsecLength ) + paUsecLength;
         }
 
         // Compute the whole sequence length
         return 1 + TLV.getNbBytes( paEncTsEncLength ) + paEncTsEncLength;
     }
 
 
     /**
      * Encode the PA-ENC-TS-ENC message to a PDU. 
      * 
      * <pre>
      * PA-ENC-TS-ENC :
      * 
      * 0x30 LL
      *   0xA0 0x11 
      *     0x18 0x0F patimestamp
      *  [0xA1 LL 
      *     0x02 LL pausec]
      * </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 PA-ENC-TS-ENC SEQ Tag
             buffer.put( UniversalTag.SEQUENCE.getValue() );
             buffer.put( TLV.getBytes( paEncTsEncLength ) );
 
             // The patimestamp, first the tag, then the value
             buffer.put( ( byte ) KerberosConstants.PA_ENC_TS_ENC_PA_TIMESTAMP_TAG );
             buffer.put( ( byte ) 0x11 );
 
             buffer.put( UniversalTag.GENERALIZED_TIME.getValue() );
             buffer.put( ( byte ) 0x0F );
             buffer.put( patimestamp.getBytes() );
 
             // The pausec, first the tag, then the value, if any
             if ( pausec != null )
             {
                 buffer.put( ( byte ) KerberosConstants.PA_ENC_TS_ENC_PA_USEC_TAG );
                 buffer.put( TLV.getBytes( paUsecLength ) );
                 BerValue.encode( buffer, pausec );
             }
         }
         catch ( BufferOverflowException boe )
         {
             log.error( I18n.err( I18n.ERR_140, 1 + TLV.getNbBytes( paEncTsEncLength ) + paEncTsEncLength,
                 buffer.capacity() ) );
             throw new EncoderException( I18n.err( I18n.ERR_138 ), boe );
         }
 
         if ( IS_DEBUG )
         {
             log.debug( "Checksum encoding : {}", Strings.dumpBytes( buffer.array() ) );
             log.debug( "Checksum 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( "PA-ENC-TS-ENC : {\n" );
         sb.append( tabs ).append( "    patimestamp : " ).append( patimestamp ).append( '\n' );
 
         if ( pausec != null )
         {
             sb.append( tabs + "    pausec :" ).append( pausec ).append( '\n' );
         }
 
         sb.append( tabs + "}\n" );
 
         return sb.toString();
     }
 }