/*
    *  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.Arrays;
  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.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.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  
  /**
   * Store a list of ETYPE-INFO
   * 
   * The ASN.1 grammar is :
   * <pre>
   * ETYPE-INFO              ::= SEQUENCE OF &lt;ETYPE-INFO-ENTRY&gt;
   * </pre>
   * @author <a href="mailto:dev@directory.apache.org">Apache Directory Project</a>
   */
  public class ETypeInfo implements Asn1Object
  {
      /** The logger */
      private static final Logger LOG = LoggerFactory.getLogger( ETypeInfo.class );
  
      /** Speedup for logs */
      private static final boolean IS_DEBUG = LOG.isDebugEnabled();
  
      /** List of all ETYPE-INFO-ENTRY stored */
      private List<ETypeInfoEntry> etypeInfoEntries;
  
      // Storage for computed lengths
      private int etypeInfoLength;
  
  
      /**
       * Creates a new instance of ETypeInfo.
       */
      public ETypeInfo()
      {
          this.etypeInfoEntries = new ArrayList<>();
      }
  
  
      /**
       * Creates a new instance of ETypeInfo.
       *
       * @param etypeInfoEntries The associated etypeInfoEntries
       */
      public ETypeInfo( ETypeInfoEntry[] etypeInfoEntries )
      {
          if ( etypeInfoEntries == null )
          {
              this.etypeInfoEntries = new ArrayList<>();
          }
          else
          {
              this.etypeInfoEntries = Arrays.asList( etypeInfoEntries );
          }
      }
  
  
      /**
       * Adds an {@link ETypeInfoEntry} to the list
       * @param etypeInfoEntry The ETypeInfoEntry to add
       */
      public void addETypeInfoEntry( ETypeInfoEntry etypeInfoEntry )
      {
          etypeInfoEntries.add( etypeInfoEntry );
      }
  
  
     /**
      * Returns true if this {@link ETypeInfoEntry} contains a specified {@link ETypeInfoEntry}.
      *
      * @param etypeInfoEntry The etypeInfoEntry we are looking for in the existing list
      * @return true if this {@link ETypeInfoEntry} contains a specified {@link ETypeInfoEntry}.
      */
     public boolean contains( ETypeInfoEntry etypeInfoEntry )
     {
         if ( etypeInfoEntries != null )
         {
             return etypeInfoEntries.contains( etypeInfoEntry );
         }
 
         return false;
     }
 
 
     /**
      * {@inheritDoc}
      */
     @Override
     public int hashCode()
     {
         int hash = 37;
 
         if ( etypeInfoEntries != null )
         {
             hash = hash * 17 + etypeInfoEntries.size();
 
             for ( ETypeInfoEntry etypeInfoEntry : etypeInfoEntries )
             {
                 hash = hash * 17 + etypeInfoEntry.hashCode();
             }
         }
 
         return hash;
     }
 
 
     /**
      * Returns true if two {@link ETypeInfo} are equal.
      *
      * @param that The {@link ETypeInfo} we want to compare with the current one
      * @return true if two {@link ETypeInfo} are equal.
      */
     public boolean equals( ETypeInfo that )
     {
         if ( that == null )
         {
             return false;
         }
 
         // infoEntries can't be null after creation
         if ( etypeInfoEntries.size() != that.etypeInfoEntries.size() )
         {
             return false;
         }
 
         for ( int i = 0; i < etypeInfoEntries.size(); i++ )
         {
             if ( !etypeInfoEntries.get( i ).equals( that.etypeInfoEntries.get( i ) ) )
             {
                 return false;
             }
         }
 
         return true;
     }
 
 
     /**
      * Returns the contained {@link ETypeInfoEntry}s as an array.
      *
      * @return An array of {@link ETypeInfoEntry}s.
      */
     public ETypeInfoEntry[] getETypeInfoEntries()
     {
         return etypeInfoEntries.toArray( new ETypeInfoEntry[0] );
     }
 
 
     /**
      * Compute the ETypeInfo length
      * <pre>
      * ETypeInfo :
      * 
      * 0x30 L1 ETypeInfo sequence of ETypeInfoEntry
      *  |
      *  +--&gt; 0x30 L2[1] ETypeInfoEntry[1]
      *  |
      *  +--&gt; 0x30 L2[2] ETypeInfoEntry[2]
      *  |
      *  ...
      *  |
      *  +--&gt; 0x30 L2[n] ETypeInfoEntry[n]
      *        
      *  where L1 = sum( L2[1], l2[2], ..., L2[n] )
      * </pre>
      */
     public int computeLength()
     {
         // Compute the ETypeInfo length.
         etypeInfoLength = 0;
 
         if ( ( etypeInfoEntries != null ) && !etypeInfoEntries.isEmpty() )
         {
             for ( ETypeInfoEntry infoEntry : etypeInfoEntries )
             {
                 int length = infoEntry.computeLength();
                 etypeInfoLength += length;
             }
         }
 
         return 1 + TLV.getNbBytes( etypeInfoLength ) + etypeInfoLength;
     }
 
 
     /**
      * Encode the ETypeInfo message to a PDU. 
      * <pre>
      * ETypeInfo :
      * 
      * 0x30 LL
      *   0x30 LL ETypeInfoEntry[1] 
      *   0x30 LL ETypeInfoEntry[1]
      *   ... 
      *   0x30 LL ETypeInfoEntry[1] 
      * </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 ETypeInfoEntry SEQ Tag
             buffer.put( UniversalTag.SEQUENCE.getValue() );
             buffer.put( TLV.getBytes( etypeInfoLength ) );
 
             // The ETypeInfoEntry list, if it's not empty
             if ( ( etypeInfoEntries != null ) && !etypeInfoEntries.isEmpty() )
             {
                 for ( ETypeInfoEntry infoEntry : etypeInfoEntries )
                 {
                     infoEntry.encode( buffer );
                 }
             }
         }
         catch ( BufferOverflowException boe )
         {
             LOG.error( I18n.err( I18n.ERR_144, 1 + TLV.getNbBytes( etypeInfoLength )
                 + etypeInfoLength, buffer.capacity() ) );
             throw new EncoderException( I18n.err( I18n.ERR_138 ), boe );
         }
 
         if ( IS_DEBUG )
         {
             LOG.debug( "ETYPE-INFO encoding : {}", Strings.dumpBytes( buffer.array() ) );
             LOG.debug( "ETYPE-INFO initial value : {}", this );
         }
 
         return buffer;
     }
 
 
     /**
      * @see Object#toString()
      */
     public String toString()
     {
         StringBuilder sb = new StringBuilder();
         boolean isFirst = true;
 
         for ( ETypeInfoEntry infoEntry : etypeInfoEntries )
         {
             if ( isFirst )
             {
                 isFirst = false;
             }
             else
             {
                 sb.append( ", " );
             }
 
             sb.append( infoEntry.toString() );
         }
 
         return sb.toString();
     }
 }