/*
    *  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.messages;
  
  
  import java.nio.BufferOverflowException;
  import java.nio.ByteBuffer;
  
  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.KerberosMessageType;
  import org.apache.directory.shared.kerberos.KerberosTime;
  import org.apache.directory.shared.kerberos.components.AuthorizationData;
  import org.apache.directory.shared.kerberos.components.Checksum;
  import org.apache.directory.shared.kerberos.components.EncryptionKey;
  import org.apache.directory.shared.kerberos.components.PrincipalName;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  
  /**
   * A structure to hold the authenticator data.
   *  It will store the object described by the ASN.1 grammar :
   * <pre>
   * Authenticator   ::= [APPLICATION 2] SEQUENCE  {
   *         authenticator-vno       [0] INTEGER (5),
   *         crealm                  [1] Realm,
   *         cname                   [2] &lt;PrincipalName&gt;,
   *         cksum                   [3] &lt;Checksum&gt; OPTIONAL,
   *         cusec                   [4] Microseconds,
   *         ctime                   [5] KerberosTime,
   *         subkey                  [6] &lt;EncryptionKey&gt; OPTIONAL,
   *         seq-number              [7] UInt32 OPTIONAL,
   *         authorization-data      [8] &lt;AuthorizationData&gt; OPTIONAL
   * }
   * </pre>
   * @author <a href="mailto:dev@directory.apache.org">Apache Directory Project</a>
   */
  public class Authenticator extends KerberosMessage
  {
      /** The logger */
      private static final Logger LOG = LoggerFactory.getLogger( Authenticator.class );
  
      /** Speedup for logs */
      private static final boolean IS_DEBUG = LOG.isDebugEnabled();
  
      /** The authenticator version number */
      private int versionNumber;
  
      /** The client realm */
      private String crealm;
  
      /** The client principalName */
      private PrincipalName cname;
  
      /** The checksum */
      private Checksum cksum;
  
      /** The client microseconds */
      private int cusec;
  
      /** The client time */
      private KerberosTime ctime;
  
      /** The sub-session key */
      private EncryptionKey subKey;
  
      /** The sequence number */
      private Integer seqNumber;
  
      /** The authorization Data */
      private AuthorizationData authorizationData;
  
      // Storage for computed lengths
      private int authenticatorVnoLength;
      private int crealmLength;
      private byte[] crealmBytes;
     private int cnameLength;
     private int cksumLength;
     private int cusecLength;
     private int ctimeLength;
     private int subkeyLength;
     private int seqNumberLength;
     private int authorizationDataLength;
     private int authenticatorSeqLength;
     private int authenticatorLength;
 
 
     /**
      * Creates a new instance of Authenticator.
      */
     public Authenticator()
     {
         super( KerberosMessageType.AUTHENTICATOR );
         versionNumber = getProtocolVersionNumber();
     }
 
 
     /**
      * Returns the {@link AuthorizationData}.
      *
      * @return The {@link AuthorizationData}.
      */
     public AuthorizationData getAuthorizationData()
     {
         return authorizationData;
     }
 
 
     /**
      * @param authorizationData the authorizationData to set
      */
     public void setAuthorizationData( AuthorizationData authorizationData )
     {
         this.authorizationData = authorizationData;
     }
 
 
     /**
      * @return the cksum
      */
     public Checksum getCksum()
     {
         return cksum;
     }
 
 
     /**
      * @param cksum the cksum to set
      */
     public void setCksum( Checksum cksum )
     {
         this.cksum = cksum;
     }
 
 
     /**
      * @return the cname
      */
     public PrincipalName getCName()
     {
         return cname;
     }
 
 
     /**
      * @param cname the cname to set
      */
     public void setCName( PrincipalName cname )
     {
         this.cname = cname;
     }
 
 
     /**
      * @return the crealm
      */
     public String getCRealm()
     {
         return crealm;
     }
 
 
     /**
      * @param crealm the crealm to set
      */
     public void setCRealm( String crealm )
     {
         this.crealm = crealm;
     }
 
 
     /**
      * @return the ctime
      */
     public KerberosTime getCtime()
     {
         return ctime;
     }
 
 
     /**
      * @param ctime the ctime to set
      */
     public void setCTime( KerberosTime ctime )
     {
         this.ctime = ctime;
     }
 
 
     /**
      * @return the cusec
      */
     public int getCusec()
     {
         return cusec;
     }
 
 
     /**
      * @param cusec the cusec to set
      */
     public void setCusec( int cusec )
     {
         this.cusec = cusec;
     }
 
 
     /**
      * @return the seqNumber
      */
     public Integer getSeqNumber()
     {
         return seqNumber;
     }
 
 
     /**
      * @param seqNumber the seqNumber to set
      */
     public void setSeqNumber( int seqNumber )
     {
         this.seqNumber = Integer.valueOf( seqNumber );
     }
 
 
     /**
      * @return the subKey
      */
     public EncryptionKey getSubKey()
     {
         return subKey;
     }
 
 
     /**
      * @param subKey the subKey to set
      */
     public void setSubKey( EncryptionKey subKey )
     {
         this.subKey = subKey;
     }
 
 
     /**
      * Returns the version number of the {@link Authenticator}.
      *
      * @return The version number of the {@link Authenticator}.
      */
     public int getVersionNumber()
     {
         return versionNumber;
     }
 
 
     /**
      * @param versionNumber the versionNumber to set
      */
     public void setVersionNumber( int versionNumber )
     {
         this.versionNumber = versionNumber;
     }
 
 
     /**
      * Compute the Authenticator length
      * <pre>
      * Authenticator :
      * 
      * 0x62 L1 Authenticator [APPLICATION 2]
      *  |
      *  +--&gt; 0x30 L2 Authenticator SEQUENCE
      *        |
      *        +--&gt; 0xA0 03 authenticator-vno tag
      *        |     |
      *        |     +--&gt; 0x02 0x01 0x05 authenticator-vno (int, 5)
      *        |
      *        +--&gt; 0xA1 L3 crealm tag
      *        |     |
      *        |     +--&gt; 0x1B L3-1 crealm (KerberosString)
      *        |
      *        +--&gt; 0xA2 L4 cname (PrincipalName)
      *        |
      *        +--&gt; 0xA3 L5 cksum (CheckSum)
      *        |
      *        +--&gt; 0xA4 L6 cusec tag
      *        |     |
      *        |     +--&gt; 0x02 L6-1 nnn cusec value (Integer)
      *        |
      *        +--&gt; 0xA5 0x11 ctime tag
      *        |     |
      *        |     +--&gt; 0x18 0x0F ttt ctime (KerberosTime)
      *        |
      *        +--&gt; 0xA6 L7 subkey (EncryptionKey)
      *        |
      *        +--&gt; 0xA7 L8 seq-number tag
      *        |     |
      *        |     +--&gt; 0x02 L8-1 nnn seq-number (Integer)
      *        |
      *        +--&gt; 0xA8 L9 authorization-data (AuthorizationData)
      * </pre>
      */
     @Override
     public int computeLength()
     {
         reset();
 
         // Compute the Authenticator version length.
         authenticatorVnoLength = 1 + 1 + BerValue.getNbBytes( getVersionNumber() );
         authenticatorSeqLength =  1 + TLV.getNbBytes( authenticatorVnoLength ) + authenticatorVnoLength;
 
         // Compute the  crealm length.
         crealmBytes = Strings.getBytesUtf8( crealm );
         crealmLength = 1 + TLV.getNbBytes( crealmBytes.length ) + crealmBytes.length;
         authenticatorSeqLength += 1 + TLV.getNbBytes( crealmLength ) + crealmLength;
 
         // Compute the cname length
         cnameLength = cname.computeLength();
         authenticatorSeqLength += 1 + TLV.getNbBytes( cnameLength ) + cnameLength;
 
         // Compute the cksum length if any
         if ( cksum != null )
         {
             cksumLength = cksum.computeLength();
             authenticatorSeqLength += 1 + TLV.getNbBytes( cksumLength ) + cksumLength;
         }
 
         // Compute the cusec length
         cusecLength = 1 + 1 + BerValue.getNbBytes( cusec );
         authenticatorSeqLength += 1 + TLV.getNbBytes( cusecLength ) + cusecLength;
 
         // Compute the ctime length
         ctimeLength = 1 + 1 + 0x0F;
         authenticatorSeqLength += 1 + 1 + ctimeLength;
 
         // Compute the subkey length if any
         if ( subKey != null )
         {
             subkeyLength = subKey.computeLength();
             authenticatorSeqLength += 1 + TLV.getNbBytes( subkeyLength ) + subkeyLength;
         }
 
         // Compute the seq-number  length if any
         if ( seqNumber != null )
         {
             seqNumberLength = 1 + 1 + BerValue.getNbBytes( seqNumber );
             authenticatorSeqLength += 1 + TLV.getNbBytes( seqNumberLength ) + seqNumberLength;
         }
 
         // Compute the authorization-data length if any
         if ( authorizationData != null )
         {
             authorizationDataLength = authorizationData.computeLength();
             authenticatorSeqLength += 1 + TLV.getNbBytes( authorizationDataLength ) + authorizationDataLength;
         }
 
         // compute the global size
         authenticatorLength = 1 + TLV.getNbBytes( authenticatorSeqLength ) + authenticatorSeqLength;
 
         return 1 + TLV.getNbBytes( authenticatorLength ) + authenticatorLength;
     }
 
 
     /**
      * Encode the Authenticator message to a PDU.
      * <pre>
      * Authenticator :
      * 
      * 0x62 LL
      *   0x30 LL
      *     0xA0 0x03
      *       0x02 0x01 0x05 authenticator-vno
      *     0xA1 LL
      *       0x1B LL abcd crealm
      *     0xA2 LL
      *       0x30 LL abcd cname
      *    [0xA3 LL
      *       0x30 LL abcd] cksum
      *     0xA4 LL
      *       0x02 LL nnn  cusec
      *     0xA5 0x11
      *       0x18 0x0F ttt ctime
      *    [0xA6 LL
      *       0x30 LL abcd] subkey
      *    [0xA7 LL
      *       0x02 LL nnn] seq-number
      *    [0xA8 LL
      *       0x30 LL abcd] authorization-data
      * </pre>
      * @return The constructed PDU.
      */
     @Override
     public ByteBuffer encode( ByteBuffer buffer ) throws EncoderException
     {
         if ( buffer == null )
         {
             buffer = ByteBuffer.allocate( computeLength() );
         }
 
         try
         {
             // The Authenticator APPLICATION Tag
             buffer.put( ( byte ) KerberosConstants.AUTHENTICATOR_TAG );
             buffer.put( TLV.getBytes( authenticatorLength ) );
 
             // The Authenticator SEQUENCE Tag
             buffer.put( UniversalTag.SEQUENCE.getValue() );
             buffer.put( TLV.getBytes( authenticatorSeqLength ) );
 
             // The authenticator-vno ------------------------------------------
             // The tag
             buffer.put( ( byte ) KerberosConstants.AUTHENTICATOR_AUTHENTICATOR_VNO_TAG );
             buffer.put( TLV.getBytes( authenticatorVnoLength ) );
 
             // The value
             BerValue.encode( buffer, getVersionNumber() );
             
             // The crealm -----------------------------------------------------
             // The tag
             buffer.put( ( byte ) KerberosConstants.AUTHENTICATOR_CREALM_TAG );
             buffer.put( TLV.getBytes( crealmLength ) );
 
             // The value
             buffer.put( UniversalTag.GENERAL_STRING.getValue() );
             buffer.put( TLV.getBytes( crealmBytes.length ) );
             buffer.put( crealmBytes );
 
             // The cname ------------------------------------------------------
             // The tag
             buffer.put( ( byte ) KerberosConstants.AUTHENTICATOR_CNAME_TAG );
             buffer.put( TLV.getBytes( cnameLength ) );
 
             // The value
             cname.encode( buffer );
 
             // The cksum, if any ----------------------------------------------
             if ( cksum != null )
             {
                 // The tag
                 buffer.put( ( byte ) KerberosConstants.AUTHENTICATOR_CKSUM_TAG );
                 buffer.put( TLV.getBytes( cksumLength ) );
 
                 // The value
                 cksum.encode( buffer );
             }
 
             // The cusec ------------------------------------------------------
             // The tag
             buffer.put( ( byte ) KerberosConstants.AUTHENTICATOR_CUSEC_TAG );
             buffer.put( TLV.getBytes( cusecLength ) );
 
             // The value
             BerValue.encode( buffer, cusec );
 
             // The ctime ------------------------------------------------------
             // The tag
             buffer.put( ( byte ) KerberosConstants.AUTHENTICATOR_CTIME_TAG );
             buffer.put( TLV.getBytes( ctimeLength ) );
 
             // The value
             buffer.put( UniversalTag.GENERALIZED_TIME.getValue() );
             buffer.put( ( byte ) 0x0F );
             buffer.put( ctime.getBytes() );
 
             // The subkey if any ---------------------------------------------------
             if ( subKey != null )
             {
                 // The tag
                 buffer.put( ( byte ) KerberosConstants.AUTHENTICATOR_SUBKEY_TAG );
                 buffer.put( TLV.getBytes( subkeyLength ) );
 
                 // The value
                 subKey.encode( buffer );
             }
 
             // The seq-number, if any -----------------------------------------
             if ( seqNumber != null )
             {
                 // The tag
                 buffer.put( (byte)KerberosConstants.AUTHENTICATOR_SEQ_NUMBER_TAG );
                 buffer.put( TLV.getBytes( seqNumberLength ) );
                 
                 // The value
                 BerValue.encode( buffer, seqNumber );
             }
             
             // The authorization-data, if any ---------------------------------
             if ( authorizationData != null )
             {
                 // The tag
                 buffer.put( ( byte ) KerberosConstants.AUTHENTICATOR_AUTHORIZATION_DATA_TAG );
                 buffer.put( TLV.getBytes( authorizationDataLength ) );
 
                 // The value
                 authorizationData.encode( buffer );
             }
         }
         catch ( BufferOverflowException boe )
         {
             LOG.error( I18n.err( I18n.ERR_139, 1 + TLV.getNbBytes( 0 )
                 + 0, buffer.capacity() ) );
             throw new EncoderException( I18n.err( I18n.ERR_138 ), boe );
         }
 
         if ( IS_DEBUG )
         {
             LOG.debug( "Authenticator encoding : {}", Strings.dumpBytes( buffer.array() ) );
             LOG.debug( "Authenticator initial value : {}", this );
         }
 
         return buffer;
     }
 
 
     /**
      * reset the fields used while computing length
      */
     private void reset()
     {
         authenticatorVnoLength = 0;
         crealmLength = 0;
         crealmBytes = null;
         cnameLength = 0;
         cksumLength = 0;
         cusecLength = 0;
         ctimeLength = 0;
         subkeyLength = 0;
         seqNumberLength = 0;
         authorizationDataLength = 0;
         authenticatorSeqLength = 0;
         authenticatorLength = 0;
     }
 
 
     /**
      * @see Object#toString()
      */
     public String toString()
     {
         StringBuilder sb = new StringBuilder();
 
         sb.append( "Authenticator : \n" );
 
         sb.append( "    authenticator-vno : " ).append( getVersionNumber() ).append( '\n' );
         sb.append( "    crealm : " ).append( crealm ).append( '\n' );
         sb.append( "    cname : " ).append( cname ).append( '\n' );
 
         if ( cksum != null )
         {
             sb.append( "    cksum : " ).append( cksum ).append( '\n' );
         }
 
         sb.append( "    cusec : " ).append( cusec ).append( '\n' );
         sb.append( "    ctime : " ).append( ctime ).append( '\n' );
 
         if ( subKey != null )
         {
             sb.append( "    subkey : " ).append( subKey ).append( '\n' );
         }
 
         if ( seqNumber != null )
         {
             sb.append( "    seq-number : " ).append( seqNumber ).append( '\n' );
         }
 
         if ( authorizationData != null )
         {
             sb.append( "    authorization-data : " ).append( authorizationData ).append( '\n' );
         }
 
         return sb.toString();
     }
 }