/*
 * 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
 * trunk/opends/resource/legal-notices/OpenDS.LICENSE
 * or https://OpenDS.dev.java.net/OpenDS.LICENSE.
 * 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
 * trunk/opends/resource/legal-notices/OpenDS.LICENSE.  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 2009 Sun Microsystems, Inc.
 */

package org.opends.server.replication.common;

import java.util.ArrayList;
import java.util.Collections;
import java.util.HashSet;
import java.util.List;
import java.util.Set;

import org.opends.messages.Message;
import org.opends.server.admin.server.ConfigurationChangeListener;
import org.opends.server.admin.std.server.UserDefinedVirtualAttributeCfg;
import org.opends.server.api.VirtualAttributeProvider;
import org.opends.server.config.ConfigException;
import org.opends.server.core.DirectoryServer;
import org.opends.server.core.SearchOperation;
import org.opends.server.replication.plugin.MultimasterReplication;
import org.opends.server.replication.server.ReplicationServer;
import org.opends.server.types.AttributeValue;
import org.opends.server.types.AttributeValues;
import org.opends.server.types.ByteString;
import org.opends.server.types.ConfigChangeResult;
import org.opends.server.types.Entry;
import org.opends.server.types.InitializationException;
import org.opends.server.types.ResultCode;
import org.opends.server.types.VirtualAttributeRule;
import org.opends.server.util.ServerConstants;
import org.opends.server.workflowelement.externalchangelog.ECLWorkflowElement;

/**
 * This class implements a virtual attribute provider in the root-dse entry
 * that contains the last (newest) cookie (cross domain state)
 * available in the server.
 */
public class LastCookieVirtualProvider
   extends VirtualAttributeProvider<UserDefinedVirtualAttributeCfg>
   implements ConfigurationChangeListener<UserDefinedVirtualAttributeCfg>
{

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

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



  /**
   * {@inheritDoc}
   */
  @Override()
  public void initializeVirtualAttributeProvider(
                            UserDefinedVirtualAttributeCfg configuration)
         throws ConfigException, InitializationException
  {
    // No initialization required
  }



  /**
   * {@inheritDoc}
   */
  @Override()
  public void finalizeVirtualAttributeProvider()
  {
    //
  }

  /**
   * {@inheritDoc}
   */
  @Override()
  public boolean hasValue(Entry entry, VirtualAttributeRule rule)
  {
    // Indicates whether this virtual attribute provider will generate
    // at least one value for the provided entry.
    // True is the DN is the one of the root DSE : "".
    return entry.getDN().toNormalizedString().equalsIgnoreCase("");

  }

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



  /**
   * {@inheritDoc}
   */
  @Override()
  public Set<AttributeValue> getValues(Entry entry,VirtualAttributeRule rule)
  {
    Set<AttributeValue> values = new HashSet<AttributeValue>();
    try
    {
      ECLWorkflowElement eclwe = (ECLWorkflowElement)
      DirectoryServer.getWorkflowElement("EXTERNAL CHANGE LOG");
      if (eclwe!=null)
      {
        // Set a list of excluded domains (also exclude 'cn=changelog' itself)
        ArrayList<String> excludedDomains =
          MultimasterReplication.getPrivateDomains();
        if (!excludedDomains.contains(
            ServerConstants.DN_EXTERNAL_CHANGELOG_ROOT))
          excludedDomains.add(ServerConstants.DN_EXTERNAL_CHANGELOG_ROOT);

        ReplicationServer rs = eclwe.getReplicationServer();
        MultiDomainServerState lastCookie =
          rs.getLastECLCookie(excludedDomains);

        AttributeValue value =
          AttributeValues.create(
              ByteString.valueOf(lastCookie.toString()),
              ByteString.valueOf(lastCookie.toString()));
        values=Collections.singleton(value);
      }
      return values;
    }
    catch(Exception e)
    {
      return values;
    }
  }

  /**
   * {@inheritDoc}
   */
  @Override()
  public boolean isSearchable(VirtualAttributeRule rule,
                              SearchOperation searchOperation)
  {
    // We will not allow searches based only on user-defined virtual attributes.
    return false;
  }



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



  /**
   * {@inheritDoc}
   */
  public boolean isConfigurationChangeAcceptable(
                      UserDefinedVirtualAttributeCfg configuration,
                      List<Message> unacceptableReasons)
  {
    return false;
  }



  /**
   * {@inheritDoc}
   */
  public ConfigChangeResult applyConfigurationChange(
                                 UserDefinedVirtualAttributeCfg configuration)
  {
    return new ConfigChangeResult(ResultCode.OTHER, false);
  }
}