/*
 * 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 2009-2010 Sun Microsystems, Inc.
 *      Portions Copyright 2014-2015 ForgeRock AS
 */
package org.opends.server.backends.pluggable;

import static org.opends.messages.JebMessages.*;
import static org.opends.server.util.ServerConstants.*;

import java.util.*;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.CountDownLatch;

import org.forgerock.i18n.slf4j.LocalizedLogger;
import org.opends.server.backends.pluggable.Importer.DNCache;
import org.opends.server.backends.pluggable.spi.ReadableTransaction;
import org.opends.server.backends.pluggable.spi.StorageRuntimeException;
import org.opends.server.backends.pluggable.spi.WriteableTransaction;
import org.opends.server.types.AttributeType;
import org.opends.server.types.DN;

/**
 * The class represents a suffix that is to be loaded during an import, or
 * rebuild index process. Multiple instances of this class can be instantiated
 * during and import to support multiple suffixes in a backend. A rebuild
 * index has only one of these instances.
 */
class Suffix
{

  private static final LocalizedLogger logger = LocalizedLogger.getLoggerForThisClass();

  private final List<DN> includeBranches, excludeBranches;
  private final DN baseDN;
  private final EntryContainer srcEntryContainer;
  private final EntryContainer entryContainer;
  private final Object synchObject = new Object();
  private static final int PARENT_ID_SET_SIZE = 16 * 1024;
  private final ConcurrentHashMap<DN, CountDownLatch> pendingMap =
          new ConcurrentHashMap<DN, CountDownLatch>();
  private final Set<DN> parentSet = new HashSet<DN>(PARENT_ID_SET_SIZE);

  /**
   * Creates a suffix instance using the specified parameters.
   *
   * @param entryContainer The entry container pertaining to the suffix.
   * @param srcEntryContainer The original entry container.
   * @param includeBranches The include branches.
   * @param excludeBranches The exclude branches.
   */
  Suffix(EntryContainer entryContainer, EntryContainer srcEntryContainer,
         List<DN> includeBranches, List<DN> excludeBranches)
  {
    this.entryContainer = entryContainer;
    this.srcEntryContainer = srcEntryContainer;
    this.baseDN = entryContainer.getBaseDN();
    if (includeBranches != null)
    {
      this.includeBranches = includeBranches;
    }
    else
    {
      this.includeBranches = new ArrayList<DN>(0);
    }
    if (excludeBranches != null)
    {
      this.excludeBranches = excludeBranches;
    }
    else
    {
      this.excludeBranches = new ArrayList<DN>(0);
    }
  }

  /**
   * Returns the DN2ID instance pertaining to a suffix instance.
   *
   * @return A DN2ID instance that can be used to manipulate the DN2ID database.
   */
  public DN2ID getDN2ID()
  {
    return entryContainer.getDN2ID();
  }


  /**
   * Returns the ID2Entry instance pertaining to a suffix instance.
   *
   * @return A ID2Entry instance that can be used to manipulate the ID2Entry
   *       database.
   */
  public ID2Entry getID2Entry()
  {
    return entryContainer.getID2Entry();
  }


  /**
   * Returns the DN2URI instance pertaining to a suffix instance.
   *
   * @return A DN2URI instance that can be used to manipulate the DN2URI
   *        database.
   */
  public DN2URI getDN2URI()
  {
    return entryContainer.getDN2URI();
  }


  /**
   * Returns the entry container pertaining to a suffix instance.
   *
   * @return The entry container used to create a suffix instance.
   */
  public EntryContainer getEntryContainer()
  {
    return entryContainer;
  }


  /**
   * Return the Attribute Type - Index map used to map an attribute type to an
   * index instance.
   *
   * @return A suffixes Attribute Type - Index map.
   */
  public Map<AttributeType, AttributeIndex> getAttrIndexMap()
  {
    return entryContainer.getAttributeIndexMap();
  }


  /**
   * Make sure the specified parent DN is not in the pending map.
   *
   * @param parentDN The DN of the parent.
   */
  private void assureNotPending(DN parentDN)  throws InterruptedException
  {
    final CountDownLatch l = pendingMap.get(parentDN);
    if (l != null)
    {
      l.await();
    }
  }


  /**
   * Add specified DN to the pending map.
   *
   * @param dn The DN to add to the map.
   */
  public void addPending(DN dn)
  {
    pendingMap.putIfAbsent(dn, new CountDownLatch(1));
  }


  /**
   * Remove the specified DN from the pending map, it may not exist if the
   * entries are being migrated so just return.
   *
   * @param dn The DN to remove from the map.
   */
  public void removePending(DN dn)
  {
    CountDownLatch l = pendingMap.remove(dn);
    if(l != null)
    {
      l.countDown();
    }
  }


  /**
   * Return {@code true} if the specified dn is contained in the parent set, or
   * in the specified DN cache. This would indicate that the parent has already
   * been processed. It returns {@code false} otherwise.
   *
   * It will optionally check the dn2id database for the dn if the specified
   * cleared backend boolean is {@code true}.
   *
   * @param txn The database transaction
   * @param dn The DN to check for.
   * @param dnCache The importer DN cache.
   * @param clearedBackend Set to {@code true} if the import process cleared the
   *                       backend before processing.
   * @return {@code true} if the dn is contained in the parent ID, or
   *         {@code false} otherwise.
   *
   * @throws StorageRuntimeException If an error occurred searching the DN cache, or
   *                           dn2id database.
   * @throws InterruptedException If an error occurred processing the pending
   *                              map.
   */
  public boolean isParentProcessed(ReadableTransaction txn, DN dn, DNCache dnCache, boolean clearedBackend)
      throws StorageRuntimeException, InterruptedException {
    synchronized(synchObject) {
      if(parentSet.contains(dn))
      {
        return true;
      }
    }
    //The DN was not in the parent set. Make sure it isn't pending.
    try {
      assureNotPending(dn);
    } catch (InterruptedException e) {
      logger.error(ERR_JEB_IMPORT_LDIF_PENDING_ERR, e.getMessage());
      throw e;
    }
    // Either parent is in the DN cache,
    // or else check the dn2id database for the DN (only if backend wasn't cleared)
    final boolean parentThere = dnCache.contains(dn)
        || (!clearedBackend
            && getDN2ID().get(txn, dn) != null);
    //Add the DN to the parent set if needed.
    if (parentThere) {
      synchronized(synchObject) {
        if (parentSet.size() >= PARENT_ID_SET_SIZE) {
          Iterator<DN> iterator = parentSet.iterator();
          iterator.next();
          iterator.remove();
        }
        parentSet.add(dn);
      }
    }
    return parentThere;
  }


  /**
   * Sets the trusted status of all of the indexes, vlvIndexes, id2children
   * and id2subtree indexes.
   *
   * @param txn a non null database transaction
   * @param trusted True if the indexes should be trusted or false otherwise.
   * @throws StorageRuntimeException If an error occurred setting the indexes to trusted.
   */
  public void setIndexesTrusted(WriteableTransaction txn, boolean trusted) throws StorageRuntimeException
  {
    entryContainer.getID2Children().setTrusted(txn, trusted);
    entryContainer.getID2Subtree().setTrusted(txn, trusted);
    for (AttributeIndex attributeIndex : entryContainer.getAttributeIndexes())
    {
      setTrusted(txn, attributeIndex.getEqualityIndex(), trusted);
      setTrusted(txn, attributeIndex.getPresenceIndex(), trusted);
      setTrusted(txn, attributeIndex.getSubstringIndex(), trusted);
      setTrusted(txn, attributeIndex.getOrderingIndex(), trusted);
      setTrusted(txn, attributeIndex.getApproximateIndex(), trusted);
      Map<String, Collection<Index>> exIndexes = attributeIndex.getExtensibleIndexes();
      if(!exIndexes.isEmpty())
      {
        setTrusted(txn, exIndexes.get(EXTENSIBLE_INDEXER_ID_SUBSTRING), trusted);
        setTrusted(txn, exIndexes.get(EXTENSIBLE_INDEXER_ID_SHARED), trusted);
      }
    }
    for(VLVIndex vlvIdx : entryContainer.getVLVIndexes()) {
      vlvIdx.setTrusted(txn, trusted);
    }
  }

  private void setTrusted(WriteableTransaction txn, Index index, boolean trusted)
  {
    if (index != null)
    {
      index.setTrusted(txn, trusted);
    }
  }

  private void setTrusted(WriteableTransaction txn, Collection<Index> indexes, boolean trusted)
  {
    if (indexes != null)
    {
      for (Index subIndex : indexes)
      {
        subIndex.setTrusted(txn, trusted);
      }
    }
  }

  /**
   * Return a src entry container.
   *
   * @return  The src entry container.
   */
  public EntryContainer getSrcEntryContainer()
  {
    return this.srcEntryContainer;
  }

  /**
   * Return include branches.
   *
   * @return The include branches.
   */
  public List<DN> getIncludeBranches()
  {
    return this.includeBranches;
  }

  /**
   * Return exclude branches.
   *
   * @return the exclude branches.
   */
  public List<DN> getExcludeBranches()
  {
    return this.excludeBranches;
  }

  /**
   * Return base DN.
   *
   * @return The base DN.
   */
  public DN getBaseDN()
  {
    return this.baseDN;
  }
}