/*
    *  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 java.util.ArrayList;
  import java.util.List;
  
  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.apache.directory.shared.kerberos.codec.types.LastReqType;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  
  /**
   * The LastReq structure.
   * 
   * The ASN.1 grammar is :
   * <pre>
   * LastReq         ::=     SEQUENCE OF SEQUENCE {
   *         lr-type         [0] Int32,
   *         lr-value        [1] KerberosTime
   * }
   * </pre>
   * @author <a href="mailto:dev@directory.apache.org">Apache Directory Project</a>
   */
  public class LastReq implements Asn1Object
  {
      /** The logger */
      private static final Logger LOG = LoggerFactory.getLogger( LastReq.class );
  
      /** Speedup for logs */
      private static final boolean IS_DEBUG = LOG.isDebugEnabled();
  
      /** The list of LastReq elements */
      private List<LastReqEntry> lastReqs = new ArrayList<>();
  
      /** The current LastReqEntry being processed */
      private LastReqEntry currentLR;
  
      // Storage for computed lengths
      private int lrTypeTagLen[];
      private int lrValueTagLen[];
      private int lastReqSeqLen[];
      private int lastReqSeqSeqLen;
  
  
      /**
       * Creates a new instance of LastReq.
       */
      public LastReq()
      {
      }
  
  
      /**
       * @return the CurrentLr type
       */
      public LastReqType getCurrentLrType()
      {
          return currentLR.getLrType();
      }
  
  
      /**
       * Set the CurrentLr type
       */
      public void setCurrentLrType( LastReqType lrType )
      {
          currentLR.setLrType( lrType );
      }
  
 
     /**
      * @return the CurrentLr value
      */
     public KerberosTime getCurrentLrValue()
     {
         return currentLR.getLrValue();
     }
 
 
     /**
      * Set the CurrentLr value
      */
     public void setCurrentLrValue( KerberosTime lrValue )
     {
         currentLR.setLrValue( lrValue );
     }
 
 
     /**
      * @return the CurrentLR
      */
     public LastReqEntry getCurrentLR()
     {
         return currentLR;
     }
 
 
     /**
      * Create a new currentLR
      */
     public void createNewLR()
     {
         currentLR = new LastReqEntry();
         lastReqs.add( currentLR );
     }
 
 
     /**
      * Add a new LastReqEntry
      * @param lastReqEntry The enry to add
      */
     public void addEntry( LastReqEntry lastReqEntry )
     {
         lastReqs.add( lastReqEntry );
     }
 
 
     /**
      * @return the LastReqs
      */
     public List<LastReqEntry> getLastReqs()
     {
         return lastReqs;
     }
 
 
     /**
      * Compute the LastReq length
      * 
      * <pre>
      * LastReq :
      * 
      * 0x30 L1 LastReq
      *  |
      *  +--&gt; 0x30 L2 
      *        |
      *        +--&gt; 0xA0 L3 lr-type tag
      *        |     |
      *        |     +--&gt; 0x02 L3-1 lrType (int)
      *        |
      *        +--&gt; 0xA1 0x11 lr-value tag
      *              |
      *              +--&gt; 0x18 0x0F ttt (KerberosString)
      *  </pre>
      */
     public int computeLength()
     {
         int i = 0;
         lastReqSeqLen = new int[lastReqs.size()];
         lrTypeTagLen = new int[lastReqs.size()];
         lrValueTagLen = new int[lastReqs.size()];
         lastReqSeqSeqLen = 0;
 
         for ( LastReqEntry lre : lastReqs )
         {
             int lrTypeLen = BerValue.getNbBytes( lre.getLrType().getValue() );
             lrTypeTagLen[i] = 1 + TLV.getNbBytes( lrTypeLen ) + lrTypeLen;
             byte[] lrValyeBytes = lre.getLrValue().getBytes();
             lrValueTagLen[i] = 1 + TLV.getNbBytes( lrValyeBytes.length ) + lrValyeBytes.length;
 
             lastReqSeqLen[i] = 1 + TLV.getNbBytes( lrTypeTagLen[i] ) + lrTypeTagLen[i] +
                 1 + TLV.getNbBytes( lrValueTagLen[i] ) + lrValueTagLen[i];
 
             lastReqSeqSeqLen += 1 + TLV.getNbBytes( lastReqSeqLen[i] ) + lastReqSeqLen[i];
             i++;
         }
 
         return 1 + TLV.getNbBytes( lastReqSeqSeqLen ) + lastReqSeqSeqLen;
     }
 
 
     /**
      * Encode the LastReq message to a PDU. 
      * 
      * <pre>
      * LastReq :
      * 
      * 0x30 LL
      *   0x30 LL
      *     0xA0 LL 
      *       0x02 0x01 lrType
      *     0xA1 0x11 
      *       0x18 0x0F lrValue
      * </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 lastRequest SEQ OF Tag
             buffer.put( UniversalTag.SEQUENCE.getValue() );
             buffer.put( TLV.getBytes( lastReqSeqSeqLen ) );
 
             int i = 0;
 
             for ( LastReqEntry lre : lastReqs )
             {
                 buffer.put( UniversalTag.SEQUENCE.getValue() );
                 buffer.put( TLV.getBytes( lastReqSeqLen[i] ) );
 
                 // the lrType
                 buffer.put( ( byte ) KerberosConstants.LAST_REQ_LR_TYPE_TAG );
                 buffer.put( TLV.getBytes( lrTypeTagLen[i] ) );
                 BerValue.encode( buffer, lre.getLrType().getValue() );
 
                 // the lrValue tag
                 buffer.put( ( byte ) KerberosConstants.LAST_REQ_LR_VALUE_TAG );
                 buffer.put( TLV.getBytes( lrValueTagLen[i] ) );
 
                 // the lrValue value
                 buffer.put( UniversalTag.GENERALIZED_TIME.getValue() );
                 buffer.put( ( byte ) 0x0F );
                 buffer.put( lre.getLrValue().getBytes() );
             }
         }
         catch ( BufferOverflowException boe )
         {
             LOG.error( I18n.err( I18n.ERR_139, 1 + TLV.getNbBytes( lastReqSeqSeqLen )
                 + lastReqSeqSeqLen, buffer.capacity() ) );
             throw new EncoderException( I18n.err( I18n.ERR_138 ) , boe);
         }
 
         if ( IS_DEBUG )
         {
             LOG.debug( "LastReq encoding : {}", Strings.dumpBytes( buffer.array() ) );
             LOG.debug( "LastReq initial value : {}", this );
         }
 
         return buffer;
     }
 
 
     /**
      * @see Object#toString()
      */
     public String toString( String tabs )
     {
         StringBuilder sb = new StringBuilder();
 
         sb.append( tabs ).append( "LastReq : \n" );
 
         for ( LastReqEntry lre : lastReqs )
         {
             sb.append( lre.toString( tabs + "    " ) );
         }
 
         return sb.toString();
     }
 
 
     /**
      * @see Object#toString()
      */
     public String toString()
     {
         return toString( "" );
     }
 }