/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License, Version 1.0 only
 * (the "License").  You may not use this file except in compliance
 * with the License.
 *
 * You can obtain a copy of the license at legal-notices/CDDLv1_0.txt
 * or http://forgerock.org/license/CDDLv1.0.html.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at legal-notices/CDDLv1_0.txt.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information:
 *      Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 *
 *
 *      Copyright 2008-2009 Sun Microsystems, Inc.
 *      Portions Copyright 2012-2015 ForgeRock AS
 */
package org.opends.server.extensions;

import java.util.List;

import org.forgerock.i18n.LocalizableMessage;
import org.forgerock.i18n.slf4j.LocalizedLogger;
import org.forgerock.opendj.ldap.ByteString;
import org.forgerock.opendj.ldap.ConditionResult;
import org.forgerock.opendj.ldap.ResultCode;
import org.opends.server.admin.std.server.NumSubordinatesVirtualAttributeCfg;
import org.opends.server.api.Backend;
import org.opends.server.api.VirtualAttributeProvider;
import org.opends.server.core.DirectoryServer;
import org.opends.server.core.SearchOperation;
import org.opends.server.types.*;

import static org.opends.messages.ExtensionMessages.*;

/**
 * This class implements a virtual attribute provider that is meant to serve the
 * hasSubordinates operational attribute as described in
 * draft-ietf-boreham-numsubordinates.
 */
public class NumSubordinatesVirtualAttributeProvider
    extends VirtualAttributeProvider<NumSubordinatesVirtualAttributeCfg>
{
  private static final LocalizedLogger logger = LocalizedLogger.getLoggerForThisClass();

  /**
   * Creates a new instance of this NumSubordinates virtual attribute provider.
   */
  public NumSubordinatesVirtualAttributeProvider()
  {
    super();

    // All initialization should be performed in the
    // initializeVirtualAttributeProvider method.
  }

  /** {@inheritDoc} */
  @Override
  public boolean isMultiValued()
  {
    return false;
  }

  /** {@inheritDoc} */
  @Override
  public Attribute getValues(Entry entry, VirtualAttributeRule rule)
  {
    Backend backend = DirectoryServer.getBackend(entry.getName());

    try
    {
      long count = backend.getNumberOfChildren(entry.getName());
      if(count >= 0)
      {
        return Attributes.create(rule.getAttributeType(), String.valueOf(count));
      }
    }
    catch(DirectoryException de)
    {
      logger.traceException(de);
    }

    return Attributes.empty(rule.getAttributeType());
  }

  /** {@inheritDoc} */
  @Override
  public boolean hasValue(Entry entry, VirtualAttributeRule rule)
  {
    Backend<?> backend = DirectoryServer.getBackend(entry.getName());

    try
    {
       return backend.getNumberOfChildren(entry.getName()) >= 0;
    }
    catch(DirectoryException de)
    {
      logger.traceException(de);
      return false;
    }
  }

  /** {@inheritDoc} */
  @Override
  public boolean hasValue(Entry entry, VirtualAttributeRule rule, ByteString value)
  {
    Backend<?> backend = DirectoryServer.getBackend(entry.getName());
    try
    {
      long count = backend.getNumberOfChildren(entry.getName());
      return count >= 0 && Long.parseLong(value.toString()) == count;
    }
    catch (NumberFormatException | DirectoryException e)
    {
      logger.traceException(e);
      return false;
    }
  }

  /** {@inheritDoc} */
  @Override
  public ConditionResult matchesSubstring(Entry entry,
                                          VirtualAttributeRule rule,
                                          ByteString subInitial,
                                          List<ByteString> subAny,
                                          ByteString subFinal)
  {
    // This virtual attribute does not support substring matching.
    return ConditionResult.UNDEFINED;
  }

  /** {@inheritDoc} */
  @Override
  public ConditionResult approximatelyEqualTo(Entry entry,
                              VirtualAttributeRule rule,
                              ByteString value)
  {
    // This virtual attribute does not support approximate matching.
    return ConditionResult.UNDEFINED;
  }

  /** {@inheritDoc} */
  @Override
  public boolean isSearchable(VirtualAttributeRule rule,
                              SearchOperation searchOperation,
                              boolean isPreIndexed)
  {
    return false;
  }

  /** {@inheritDoc} */
  @Override
  public void processSearch(VirtualAttributeRule rule,
                            SearchOperation searchOperation)
  {
    searchOperation.setResultCode(ResultCode.UNWILLING_TO_PERFORM);

    LocalizableMessage message = ERR_NUMSUBORDINATES_VATTR_NOT_SEARCHABLE.get(
            rule.getAttributeType().getNameOrOID());
    searchOperation.appendErrorMessage(message);
  }
}