/*
    *  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.authz.support;
  
  
  import java.util.Collection;
  import java.util.Iterator;
  
  import javax.naming.directory.SearchControls;
  
  import org.apache.directory.api.ldap.aci.ACITuple;
  import org.apache.directory.api.ldap.aci.ProtectedItem;
  import org.apache.directory.api.ldap.aci.protectedItem.MaxImmSubItem;
  import org.apache.directory.api.ldap.model.constants.SchemaConstants;
  import org.apache.directory.api.ldap.model.entry.Entry;
  import org.apache.directory.api.ldap.model.exception.LdapException;
  import org.apache.directory.api.ldap.model.exception.LdapOperationException;
  import org.apache.directory.api.ldap.model.exception.LdapOtherException;
  import org.apache.directory.api.ldap.model.filter.ExprNode;
  import org.apache.directory.api.ldap.model.filter.PresenceNode;
  import org.apache.directory.api.ldap.model.message.AliasDerefMode;
  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.SchemaManager;
  import org.apache.directory.server.core.api.filtering.EntryFilteringCursor;
  import org.apache.directory.server.core.api.interceptor.context.OperationContext;
  import org.apache.directory.server.core.api.interceptor.context.SearchOperationContext;
  
  
  /**
   * An {@link ACITupleFilter} that discards all tuples that doesn't satisfy
   * {@link org.apache.directory.api.ldap.aci.protectedItem.MaxImmSubItem} constraint if available. (18.8.3.3, X.501)
   *
   * @author <a href="mailto:dev@directory.apache.org">Apache Directory Project</a>
   */
  public class MaxImmSubFilter implements ACITupleFilter
  {
      private final ExprNode childrenFilter;
      private final SearchControls childrenSearchControls;
  
  
      public MaxImmSubFilter( SchemaManager schemaManager )
      {
          AttributeType objectClassAt = null;
  
          try
          {
              objectClassAt = schemaManager.lookupAttributeTypeRegistry( SchemaConstants.OBJECT_CLASS_AT );
          }
          catch ( LdapException le )
          {
              // Do nothing
          }
  
          childrenFilter = new PresenceNode( objectClassAt );
          childrenSearchControls = new SearchControls();
          childrenSearchControls.setSearchScope( SearchControls.ONELEVEL_SCOPE );
      }
  
  
      /**
       * {@inheritDoc}
       */
      @Override
      public Collection<ACITuple> filter( AciContext aciContext, OperationScope scope, Entry userEntry )
          throws LdapException
      {
          ACI_LOG.debug( "Filtering MaxImmSub..." );
  
          if ( aciContext.getEntryDn().isRootDse() )
          {
              return aciContext.getAciTuples();
          }
  
          if ( aciContext.getAciTuples().isEmpty() )
          {
              return aciContext.getAciTuples();
          }
  
          if ( scope != OperationScope.ENTRY )
          {
              return aciContext.getAciTuples();
         }
 
         int immSubCount = -1;
 
         for ( Iterator<ACITuple> i = aciContext.getAciTuples().iterator(); i.hasNext(); )
         {
             ACITuple tuple = i.next();
 
             if ( !tuple.isGrant() )
             {
                 continue;
             }
 
             for ( ProtectedItem item : tuple.getProtectedItems() )
             {
                 if ( item instanceof MaxImmSubItem )
                 {
                     if ( immSubCount < 0 )
                     {
                         immSubCount = getImmSubCount( aciContext.getOperationContext(), aciContext.getEntryDn() );
                     }
 
                     MaxImmSubItem mis = ( MaxImmSubItem ) item;
 
                     if ( immSubCount >= mis.getValue() )
                     {
                         i.remove();
                         break;
                     }
                 }
             }
         }
 
         return aciContext.getAciTuples();
     }
 
 
     private int getImmSubCount( OperationContext opContext, Dn entryName ) throws LdapException
     {
         int cnt = 0;
         EntryFilteringCursor results = null;
 
         try
         {
             Dn baseDn = new Dn( opContext.getSession().getDirectoryService().getSchemaManager(),
                 entryName.getRdn( entryName.size() - 1 ) );
             SearchOperationContextceptor/context/SearchOperationContext.html#SearchOperationContext">SearchOperationContext searchContext = new SearchOperationContext( opContext.getSession(),
                 baseDn, childrenFilter, childrenSearchControls );
             searchContext.setAliasDerefMode( AliasDerefMode.DEREF_ALWAYS );
             searchContext.setPartition( opContext.getPartition() );
             searchContext.setTransaction( opContext.getTransaction() );
 
             results = opContext.getSession().getDirectoryService().getPartitionNexus().search( searchContext );
 
             try
             {
                 while ( results.next() )
                 {
                     results.get();
                     cnt++;
                 }
             }
             catch ( Exception e )
             {
                 throw new LdapOtherException( e.getMessage(), e );
             }
         }
         finally
         {
             if ( results != null )
             {
                 try
                 {
                     results.close();
                 }
                 catch ( Exception e )
                 {
                     throw new LdapOperationException( e.getMessage(), e );
                 }
             }
         }
 
         return cnt;
     }
 }