/*
    *  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.server.core.api.event;
  
  
  import java.util.regex.Pattern;
  import java.util.regex.PatternSyntaxException;
  
  import org.apache.directory.api.ldap.model.entry.Attribute;
  import org.apache.directory.api.ldap.model.entry.Entry;
  import org.apache.directory.api.ldap.model.entry.Value;
  import org.apache.directory.api.ldap.model.exception.LdapException;
  import org.apache.directory.api.ldap.model.exception.LdapInvalidSearchFilterException;
  import org.apache.directory.api.ldap.model.filter.ExprNode;
  import org.apache.directory.api.ldap.model.filter.SubstringNode;
  import org.apache.directory.api.ldap.model.name.Dn;
  import org.apache.directory.api.ldap.model.schema.AttributeType;
  import org.apache.directory.api.ldap.model.schema.MatchingRule;
  import org.apache.directory.api.ldap.model.schema.Normalizer;
  import org.apache.directory.server.i18n.I18n;
  
  
  /**
   * Evaluates substring filter assertions on an entry.
   * 
   * @author <a href="mailto:dev@directory.apache.org">Apache Directory Project</a>
   */
  public class SubstringEvaluator implements Evaluator
  {
      /**
       * Creates a new SubstringEvaluator for substring expressions.
       */
      public SubstringEvaluator()
      {
      }
  
  
      /**
       * {@inheritDoc}
       */
      public boolean evaluate( ExprNode node, Dn dn, Entry entry ) throws LdapException
      {
          Pattern regex = null;
          SubstringNode snode = ( SubstringNode ) node;
          AttributeType attributeType = snode.getAttributeType();
          MatchingRule matchingRule = attributeType.getSubstring();
  
          if ( matchingRule == null )
          {
              matchingRule = attributeType.getEquality();
          }
  
          Normalizer normalizer = matchingRule.getNormalizer();
  
          // get the attribute
          Attribute attr = entry.get( snode.getAttribute() );
  
          // if the attribute does not exist just return false
          if ( null == attr )
          {
              return false;
          }
  
          // compile the regular expression to search for a matching attribute
          try
          {
              regex = snode.getRegex( normalizer );
          }
          catch ( PatternSyntaxException pse )
          {
              LdapInvalidSearchFilterException ne = new LdapInvalidSearchFilterException( I18n.err( I18n.ERR_248, node ) );
              ne.initCause( pse );
              throw ne;
          }
  
          /*
           * Cycle through the attribute values testing normalized version 
           * obtained from using the substring matching rule's normalizer.
           * The test uses the comparator obtained from the appropriate 
           * substring matching rule.
           */
  
         for ( Value value : attr )
         {
             String normValue = normalizer.normalize( value.getString() );
 
             // Once match is found cleanup and return true
 
             if ( regex.matcher( normValue ).matches() )
             {
                 return true;
             }
         }
 
         // we fell through so a match was not found - assertion was false.
         return false;
     }
 }