/*
    *  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.kerberos.client;
  
  
  import java.nio.ByteBuffer;
  import java.util.Collections;
  import java.util.LinkedHashSet;
  import java.util.Set;
  
  import org.apache.directory.api.asn1.DecoderException;
  import org.apache.directory.api.asn1.ber.Asn1Decoder;
  import org.apache.directory.shared.kerberos.codec.etypeInfo.ETypeInfoContainer;
  import org.apache.directory.shared.kerberos.codec.etypeInfo2.ETypeInfo2Container;
  import org.apache.directory.shared.kerberos.codec.methodData.MethodDataContainer;
  import org.apache.directory.shared.kerberos.codec.types.EncryptionType;
  import org.apache.directory.shared.kerberos.codec.types.PaDataType;
  import org.apache.directory.shared.kerberos.components.ETypeInfo;
  import org.apache.directory.shared.kerberos.components.ETypeInfo2;
  import org.apache.directory.shared.kerberos.components.ETypeInfo2Entry;
  import org.apache.directory.shared.kerberos.components.ETypeInfoEntry;
  import org.apache.directory.shared.kerberos.components.MethodData;
  import org.apache.directory.shared.kerberos.components.PaData;
  import org.apache.directory.shared.kerberos.messages.KrbError;
  
  
  /**
   * A class with utility methods.
   *
   * @author <a href="mailto:dev@directory.apache.org">Apache Directory Project</a>
   */
  public class KdcClientUtil
  {
      public static String extractRealm( String principal )
      {
          int pos = principal.indexOf( '@' );
  
          if ( pos > 0 )
          {
              return principal.substring( pos + 1 );
          }
  
          throw new IllegalArgumentException( "Not a valid principal, missing realm name" );
      }
  
  
      public static String extractName( String principal )
      {
          int pos = principal.indexOf( '@' );
  
          if ( pos < 0 )
          {
              return principal;
          }
  
          return principal.substring( 0, pos );
      }
  
  
      public static Set<EncryptionType> getEtypesFromError( KrbError error )
      {
          try
          {
              ByteBuffer stream = ByteBuffer.wrap( error.getEData() );
  
              MethodDataContainerc/methodData/MethodDataContainer.html#MethodDataContainer">MethodDataContainer container = new MethodDataContainer();
              container.setStream( stream );
              Asn1Decoder.decode( stream, container );
  
              MethodData methodData = container.getMethodData();
  
              for ( PaData pd : methodData.getPaDatas() )
              {
                  if ( pd.getPaDataType() == PaDataType.PA_ENCTYPE_INFO2 )
                  {
                      return parseEtpeInfo2( pd.getPaDataValue() );
                  }
                  else if ( pd.getPaDataType() == PaDataType.PA_ENCTYPE_INFO )
                  {
                      return parseEtpeInfo( pd.getPaDataValue() );
                  }
              }
         }
         catch ( Exception e )
         {
             // shouldn't happen, but iff happens blast off
             throw new RuntimeException( e );
         }
 
         return Collections.emptySet();
     }
 
 
     private static Set<EncryptionType> parseEtpeInfo2( byte[] data ) throws DecoderException
     {
         ByteBuffer stream = ByteBuffer.wrap( data );
 
         ETypeInfo2Containerc/etypeInfo2/ETypeInfo2Container.html#ETypeInfo2Container">ETypeInfo2Container container = new ETypeInfo2Container();
         container.setStream( stream );
         Asn1Decoder.decode( stream, container );
 
         ETypeInfo2 info2 = container.getETypeInfo2();
 
         Set<EncryptionType> lstEtypes = new LinkedHashSet<>();
 
         for ( ETypeInfo2Entry e2e : info2.getETypeInfo2Entries() )
         {
             lstEtypes.add( e2e.getEType() );
         }
 
         return lstEtypes;
     }
 
 
     private static Set<EncryptionType> parseEtpeInfo( byte[] data ) throws DecoderException
     {
         ByteBuffer stream = ByteBuffer.wrap( data );
 
         ETypeInfoContainerec/etypeInfo/ETypeInfoContainer.html#ETypeInfoContainer">ETypeInfoContainer container = new ETypeInfoContainer();
         container.setStream( stream );
         Asn1Decoder.decode( stream, container );
 
         ETypeInfo einfo = container.getETypeInfo();
 
         Set<EncryptionType> lstEtypes = new LinkedHashSet<>();
 
         for ( ETypeInfoEntry eie : einfo.getETypeInfoEntries() )
         {
             lstEtypes.add( eie.getEType() );
         }
 
         return lstEtypes;
     }
 
 }