/*
 * 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
 * <p>
 * http://www.apache.org/licenses/LICENSE-2.0
 * <p>
 * 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.ozone.container.common.statemachine.commandhandler;

import java.io.IOException;
import java.util.concurrent.atomic.AtomicLong;
import java.util.List;
import java.util.stream.Collectors;

import org.apache.hadoop.hdds.conf.ConfigurationSource;
import org.apache.hadoop.hdds.protocol.DatanodeDetails;
import org.apache.hadoop.hdds.protocol.proto.HddsProtos;
import org.apache.hadoop.hdds.protocol.proto.StorageContainerDatanodeProtocolProtos.CreatePipelineCommandProto;
import org.apache.hadoop.hdds.protocol.proto.StorageContainerDatanodeProtocolProtos.SCMCommandProto;
import org.apache.hadoop.hdds.ratis.RatisHelper;
import org.apache.hadoop.hdds.scm.pipeline.PipelineID;
import org.apache.hadoop.ozone.container.common.statemachine.SCMConnectionManager;
import org.apache.hadoop.ozone.container.common.statemachine.StateContext;
import org.apache.hadoop.ozone.container.common.transport.server.XceiverServerSpi;
import org.apache.hadoop.ozone.container.ozoneimpl.OzoneContainer;
import org.apache.hadoop.ozone.protocol.commands.CreatePipelineCommand;
import org.apache.hadoop.ozone.protocol.commands.SCMCommand;
import org.apache.hadoop.util.Time;

import org.apache.ratis.client.RaftClient;
import org.apache.ratis.protocol.exceptions.AlreadyExistsException;
import org.apache.ratis.protocol.RaftGroup;
import org.apache.ratis.protocol.RaftGroupId;
import org.apache.ratis.protocol.RaftPeer;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * Handler for create pipeline command received from SCM.
 */
public class CreatePipelineCommandHandler implements CommandHandler {

  private static final Logger LOG =
      LoggerFactory.getLogger(CreatePipelineCommandHandler.class);

  private final AtomicLong invocationCount = new AtomicLong(0);
  private final ConfigurationSource conf;

  private long totalTime;

  /**
   * Constructs a createPipelineCommand handler.
   */
  public CreatePipelineCommandHandler(ConfigurationSource conf) {
    this.conf = conf;
  }

  /**
   * Handles a given SCM command.
   *
   * @param command           - SCM Command
   * @param ozoneContainer    - Ozone Container.
   * @param context           - Current Context.
   * @param connectionManager - The SCMs that we are talking to.
   */
  @Override
  public void handle(SCMCommand command, OzoneContainer ozoneContainer,
      StateContext context, SCMConnectionManager connectionManager) {
    invocationCount.incrementAndGet();
    final long startTime = Time.monotonicNow();
    final DatanodeDetails dn = context.getParent()
        .getDatanodeDetails();
    final CreatePipelineCommandProto createCommand =
        ((CreatePipelineCommand)command).getProto();
    final HddsProtos.PipelineID pipelineID = createCommand.getPipelineID();
    final List<DatanodeDetails> peers =
        createCommand.getDatanodeList().stream()
            .map(DatanodeDetails::getFromProtoBuf)
            .collect(Collectors.toList());
    final List<Integer> priorityList = createCommand.getPriorityList();

    try {
      XceiverServerSpi server = ozoneContainer.getWriteChannel();
      if (!server.isExist(pipelineID)) {
        final RaftGroupId groupId = RaftGroupId.valueOf(
            PipelineID.getFromProtobuf(pipelineID).getId());
        final RaftGroup group =
            RatisHelper.newRaftGroup(groupId, peers, priorityList);
        server.addGroup(pipelineID, peers, priorityList);
        peers.stream().filter(
            d -> !d.getUuid().equals(dn.getUuid()))
            .forEach(d -> {
              final RaftPeer peer = RatisHelper.toRaftPeer(d);
              try (RaftClient client = RatisHelper.newRaftClient(peer, conf,
                  ozoneContainer.getTlsClientConfig())) {
                client.groupAdd(group, peer.getId());
              } catch (AlreadyExistsException ae) {
                // do not log
              } catch (IOException ioe) {
                LOG.warn("Add group failed for {}", d, ioe);
              }
            });
        LOG.info("Created Pipeline {} {} #{}.",
            createCommand.getType(), createCommand.getFactor(), pipelineID);
      }
    } catch (IOException e) {
      LOG.error("Can't create pipeline {} {} #{}", createCommand.getType(),
          createCommand.getFactor(), pipelineID, e);
    } finally {
      long endTime = Time.monotonicNow();
      totalTime += endTime - startTime;
    }
  }

  /**
   * Returns the command type that this command handler handles.
   *
   * @return Type
   */
  @Override
  public SCMCommandProto.Type getCommandType() {
    return SCMCommandProto.Type.createPipelineCommand;
  }

  /**
   * Returns number of times this handler has been invoked.
   *
   * @return int
   */
  @Override
  public int getInvocationCount() {
    return (int)invocationCount.get();
  }

  /**
   * Returns the average time this function takes to run.
   *
   * @return long
   */
  @Override
  public long getAverageRunTime() {
    if (invocationCount.get() > 0) {
      return totalTime / invocationCount.get();
    }
    return 0;
  }
}