/*
 * 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 2009 Sun Microsystems, Inc.
 *      Portions Copyright 2014 ForgeRock AS
 */
package org.opends.server.api;

import java.util.Collection;
import java.util.HashSet;
import java.util.Map;
import java.util.Set;

import org.forgerock.opendj.ldap.ByteSequence;
import org.forgerock.opendj.ldap.ByteString;
import org.forgerock.opendj.ldap.DecodeException;
import org.forgerock.opendj.ldap.schema.Schema;
import org.forgerock.opendj.ldap.spi.Indexer;
import org.forgerock.opendj.ldap.spi.IndexingOptions;
import org.opends.server.types.AttributeValue;

/**
 * This class is registered with a Backend and it provides call- backs
 * for indexing attribute values. An index implementation will use
 * this interface to create the keys for an attribute value.
 */
@org.opends.server.types.PublicAPI(
    stability = org.opends.server.types.StabilityLevel.VOLATILE,
    mayInstantiate = false,
    mayExtend = true,
    mayInvoke = false)
public abstract class ExtensibleIndexer implements Indexer
{

  /**
   * Returns an index identifier associated with this indexer. An
   * identifier should be selected based on the matching rule type. A
   * unique identifier will map to a unique index database in the
   * backend implementation. If multiple matching rules need to share
   * the index database, the corresponding indexers should always use
   * the same identifier.
   *
   * @return index ID A String containing the ID associated with this
   *         indexer.
   */
  public abstract String getExtensibleIndexID();



  /**
   * Generates the set of index keys for an attribute.
   *
   * @param value
   *          The attribute value for which keys are required.
   * @param keys
   *          The set into which the generated keys will be inserted.
   */
  public abstract void getKeys(AttributeValue value, Set<byte[]> keys);

  /** {@inheritDoc} */
  @Override
  public void createKeys(Schema schema, ByteSequence value,
      IndexingOptions options, Collection<ByteString> keys)
      throws DecodeException
  {
    throw new RuntimeException("Not implemented yet");
  }

  /**
   * Generates a map of index keys and a boolean flag indicating
   * whether the corresponding key will be inserted or deleted.
   *
   * @param attrValue
   *          The attribute for which keys are required.
   * @param modifiedKeys
   *          A map containing the keys and a boolean. Keys
   *          corresponding to the boolean value <code>true</code>
   *          should be inserted and <code>false</code> should be
   *          deleted.
   * @param insert
   *          <code>true</code> if generated keys should be inserted
   *          or <code>false</code> otherwise.
   */
  public void getKeys(AttributeValue attrValue, Map<byte[], Boolean> modifiedKeys, Boolean insert)
  {
    final Set<byte[]> keys = new HashSet<byte[]>();
    getKeys(attrValue, keys);
    computeModifiedKeys(modifiedKeys, insert, keys);
  }

  /**
   * Computes the modified keys by an indexer.
   *
   * @param modifiedKeys
   *          A map containing the keys and a boolean. Keys
   *          corresponding to the boolean value <code>true</code>
   *          should be inserted and <code>false</code> should be
   *          deleted.
   * @param insert
   *          <code>true</code> if generated keys should be inserted
   *          or <code>false</code> otherwise.
   * @param keys
   *          the newly generated keys that will be added or removed from the Map
   */
  public static void computeModifiedKeys(Map<byte[], Boolean> modifiedKeys,
      Boolean insert, final Set<byte[]> keys)
  {
    for (byte[] key : keys)
    {
      Boolean cInsert = modifiedKeys.get(key);
      if (cInsert == null)
      {
        modifiedKeys.put(key, insert);
      }
      else if (!cInsert.equals(insert))
      {
        modifiedKeys.remove(key);
      }
    }
  }
}