/**
 * 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.replication.regionserver;

import java.io.IOException;
import java.util.concurrent.PriorityBlockingQueue;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.hbase.replication.ReplicationException;
import org.apache.hadoop.hbase.replication.ReplicationQueueStorage;
import org.apache.hadoop.hbase.util.Threads;
import org.apache.yetus.audience.InterfaceAudience;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 *  Used by a {@link RecoveredReplicationSource}.
 */
@InterfaceAudience.Private
public class RecoveredReplicationSourceShipper extends ReplicationSourceShipper {
  private static final Logger LOG =
      LoggerFactory.getLogger(RecoveredReplicationSourceShipper.class);

  protected final RecoveredReplicationSource source;
  private final ReplicationQueueStorage replicationQueues;

  public RecoveredReplicationSourceShipper(Configuration conf, String walGroupId,
      PriorityBlockingQueue<Path> queue, RecoveredReplicationSource source,
      ReplicationQueueStorage queueStorage) {
    super(conf, walGroupId, queue, source);
    this.source = source;
    this.replicationQueues = queueStorage;
  }

  @Override
  protected void noMoreData() {
    LOG.debug("Finished recovering queue for group {} of peer {}", walGroupId, source.getQueueId());
    source.getSourceMetrics().incrCompletedRecoveryQueue();
    setWorkerState(WorkerState.FINISHED);
  }

  @Override
  protected void postFinish() {
    source.tryFinish();
  }

  @Override
  public long getStartPosition() {
    long startPosition = getRecoveredQueueStartPos();
    int numRetries = 0;
    while (numRetries <= maxRetriesMultiplier) {
      try {
        source.locateRecoveredPaths(queue);
        break;
      } catch (IOException e) {
        LOG.error("Error while locating recovered queue paths, attempt #" + numRetries);
        numRetries++;
      }
    }
    return startPosition;
  }

  // If this is a recovered queue, the queue is already full and the first log
  // normally has a position (unless the RS failed between 2 logs)
  private long getRecoveredQueueStartPos() {
    long startPosition = 0;
    String peerClusterZNode = source.getQueueId();
    try {
      startPosition = this.replicationQueues.getWALPosition(source.getServer().getServerName(),
        peerClusterZNode, this.queue.peek().getName());
      LOG.trace("Recovered queue started with log {} at position {}", this.queue.peek(),
        startPosition);
    } catch (ReplicationException e) {
      terminate("Couldn't get the position of this recovered queue " + peerClusterZNode, e);
    }
    return startPosition;
  }

  private void terminate(String reason, Exception cause) {
    if (cause == null) {
      LOG.info("Closing worker for wal group {} because: {}", this.walGroupId, reason);
    } else {
      LOG.error(
        "Closing worker for wal group " + this.walGroupId + " because an error occurred: " + reason,
        cause);
    }
    entryReader.interrupt();
    Threads.shutdown(entryReader, sleepForRetries);
    this.interrupt();
    Threads.shutdown(this, sleepForRetries);
    LOG.info("ReplicationSourceWorker {} terminated", this.getName());
  }
}
