/**
    * 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.hadoop.hbase.master.cleaner;
  
  import java.io.IOException;
  import java.util.ArrayList;
  import java.util.HashMap;
  import java.util.HashSet;
  import java.util.List;
  import java.util.Map;
  import java.util.Set;
  import java.util.Map.Entry;
  
  import org.apache.commons.logging.Log;
  import org.apache.commons.logging.LogFactory;
  import org.apache.hadoop.conf.Configuration;
  import org.apache.hadoop.hbase.Abortable;
  import org.apache.hadoop.hbase.HConstants;
  import org.apache.hadoop.hbase.classification.InterfaceAudience;
  import org.apache.hadoop.hbase.replication.ReplicationFactory;
  import org.apache.hadoop.hbase.replication.ReplicationPeers;
  import org.apache.hadoop.hbase.replication.ReplicationQueueInfo;
  import org.apache.hadoop.hbase.replication.ReplicationQueuesClient;
  import org.apache.hadoop.hbase.replication.ReplicationQueuesZKImpl;
  import org.apache.hadoop.hbase.replication.ReplicationStateZKBase;
  import org.apache.hadoop.hbase.zookeeper.ZKUtil;
  import org.apache.hadoop.hbase.zookeeper.ZooKeeperWatcher;
  import org.apache.zookeeper.KeeperException;
  
  /**
   * Used to clean the replication queues belonging to the peer which does not exist.
   */
  @InterfaceAudience.Private
  public class ReplicationZKNodeCleaner {
    private static final Log LOG = LogFactory.getLog(ReplicationZKNodeCleaner.class);
    private final ZooKeeperWatcher zkw;
    private final ReplicationQueuesClient queuesClient;
    private final ReplicationPeers replicationPeers;
    private final ReplicationQueueDeletor queueDeletor;
    private final boolean useMulti;
  
    public ReplicationZKNodeCleaner(Configuration conf, ZooKeeperWatcher zkw, Abortable abortable)
        throws IOException {
      try {
        this.zkw = zkw;
        this.queuesClient = ReplicationFactory
            .getReplicationQueuesClient(zkw, conf, abortable);
        this.queuesClient.init();
        this.replicationPeers = ReplicationFactory.getReplicationPeers(zkw, conf, this.queuesClient,
          abortable);
        this.replicationPeers.init();
        this.queueDeletor = new ReplicationQueueDeletor(zkw, conf, abortable);
        this.useMulti = conf.getBoolean(HConstants.ZOOKEEPER_USEMULTI, true);
      } catch (Exception e) {
        throw new IOException("failed to construct ReplicationZKNodeCleaner", e);
      }
    }
  
    /**
     * @return undeletedQueues replicator with its queueIds for removed peers
     * @throws IOException
     */
    public Map<String, List<String>> getUnDeletedQueues() throws IOException {
      Map<String, List<String>> undeletedQueues = new HashMap<>();
      Set<String> peerIds = new HashSet<>(this.replicationPeers.getAllPeerIds());
      try {
        List<String> replicators = this.queuesClient.getListOfReplicators();
        if (replicators == null || replicators.isEmpty()) {
          return undeletedQueues;
        }
        for (String replicator : replicators) {
          List<String> queueIds = this.queuesClient.getAllQueues(replicator);
          for (String queueId : queueIds) {
            if (!useMulti && queueId.equals(ReplicationQueuesZKImpl.RS_LOCK_ZNODE)) {
              continue;
            }
            ReplicationQueueInfo queueInfo = new ReplicationQueueInfo(queueId);
            if (!peerIds.contains(queueInfo.getPeerId())) {
              if (!undeletedQueues.containsKey(replicator)) {
                undeletedQueues.put(replicator, new ArrayList<String>());
              }
              undeletedQueues.get(replicator).add(queueId);
              if (LOG.isDebugEnabled()) {
                LOG.debug("Undeleted replication queue for removed peer found: "
                   + String.format("[removedPeerId=%s, replicator=%s, queueId=%s]",
                     queueInfo.getPeerId(), replicator, queueId));
             }
           }
         }
       }
     } catch (KeeperException ke) {
       throw new IOException("Failed to get the replication queues of all replicators", ke);
     }
     return undeletedQueues;
   }
 
   /**
    * @return undeletedHFileRefsQueue replicator with its undeleted queueIds for removed peers in
    *         hfile-refs queue
    * @throws IOException
    */
   public Set<String> getUnDeletedHFileRefsQueues() throws IOException {
     Set<String> undeletedHFileRefsQueue = new HashSet<>();
     Set<String> peerIds = new HashSet<>(this.replicationPeers.getAllPeerIds());
     String hfileRefsZNode = queueDeletor.getHfileRefsZNode();
     try {
       if (-1 == ZKUtil.checkExists(zkw, hfileRefsZNode)) {
         return null;
       }
       List<String> listOfPeers = this.queuesClient.getAllPeersFromHFileRefsQueue();
       Set<String> peers = new HashSet<>(listOfPeers);
       peers.removeAll(peerIds);
       if (!peers.isEmpty()) {
         undeletedHFileRefsQueue.addAll(peers);
       }
     } catch (KeeperException e) {
       throw new IOException("Failed to get list of all peers from hfile-refs znode "
           + hfileRefsZNode, e);
     }
     return undeletedHFileRefsQueue;
   }
 
   private class ReplicationQueueDeletor extends ReplicationStateZKBase {
 
     public ReplicationQueueDeletor(ZooKeeperWatcher zk, Configuration conf, Abortable abortable) {
       super(zk, conf, abortable);
     }
 
     /**
      * @param replicator The regionserver which has undeleted queue
      * @param queueId The undeleted queue id
      * @throws IOException
      */
     public void removeQueue(final String replicator, final String queueId) throws IOException {
       String queueZnodePath = ZKUtil.joinZNode(ZKUtil.joinZNode(this.queuesZNode, replicator),
         queueId);
       try {
         ReplicationQueueInfo queueInfo = new ReplicationQueueInfo(queueId);
         if (!replicationPeers.getAllPeerIds().contains(queueInfo.getPeerId())) {
           ZKUtil.deleteNodeRecursively(this.zookeeper, queueZnodePath);
           LOG.info("Successfully removed replication queue, replicator: " + replicator
               + ", queueId: " + queueId);
         }
       } catch (KeeperException e) {
         throw new IOException("Failed to delete queue, replicator: " + replicator + ", queueId: "
             + queueId);
       }
     }
 
     /**
      * @param hfileRefsQueueId The undeleted hfile-refs queue id
      * @throws IOException
      */
     public void removeHFileRefsQueue(final String hfileRefsQueueId) throws IOException {
       String node = ZKUtil.joinZNode(this.hfileRefsZNode, hfileRefsQueueId);
       try {
         if (!replicationPeers.getAllPeerIds().contains(hfileRefsQueueId)) {
           ZKUtil.deleteNodeRecursively(this.zookeeper, node);
           LOG.info("Successfully removed hfile-refs queue " + hfileRefsQueueId + " from path "
               + hfileRefsZNode);
         }
       } catch (KeeperException e) {
         throw new IOException("Failed to delete hfile-refs queue " + hfileRefsQueueId
             + " from path " + hfileRefsZNode);
       }
     }
 
     String getHfileRefsZNode() {
       return this.hfileRefsZNode;
     }
   }
 
   /**
    * Remove the undeleted replication queue's zk node for removed peers.
    * @param undeletedQueues replicator with its queueIds for removed peers
    * @throws IOException
    */
   public void removeQueues(final Map<String, List<String>> undeletedQueues) throws IOException {
     for (Entry<String, List<String>> replicatorAndQueueIds : undeletedQueues.entrySet()) {
       String replicator = replicatorAndQueueIds.getKey();
       for (String queueId : replicatorAndQueueIds.getValue()) {
         queueDeletor.removeQueue(replicator, queueId);
       }
     }
   }
 
   /**
    * Remove the undeleted hfile-refs queue's zk node for removed peers.
    * @param undeletedHFileRefsQueues replicator with its undeleted queueIds for removed peers in
    *          hfile-refs queue
    * @throws IOException
    */
   public void removeHFileRefsQueues(final Set<String> undeletedHFileRefsQueues) throws IOException {
     for (String hfileRefsQueueId : undeletedHFileRefsQueues) {
       queueDeletor.removeHFileRefsQueue(hfileRefsQueueId);
     }
   }
 }