/*
    * 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.chaos.actions;
  
  import java.io.IOException;
  import java.util.ArrayList;
  import java.util.Collections;
  import java.util.HashSet;
  import java.util.List;
  import java.util.Set;
  import org.apache.hadoop.hbase.ClusterStatus;
  import org.apache.hadoop.hbase.ServerName;
  import org.apache.hadoop.hbase.net.Address;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  /**
   * Action to dump the cluster status.
   */
  public class DumpClusterStatusAction extends Action {
    private static final Logger LOG = LoggerFactory.getLogger(DumpClusterStatusAction.class);
  
    private Set<Address> initialRegionServers;
  
    @Override
    protected Logger getLogger() {
      return LOG;
    }
  
    @Override
    public void init(ActionContext context) throws IOException {
      super.init(context);
      initialRegionServers = collectKnownRegionServers(initialStatus);
    }
  
    @Override
    public void perform() throws Exception {
      getLogger().debug("Performing action: Dump cluster status");
      final ClusterStatus currentMetrics = cluster.getClusterStatus();
      getLogger().info("Cluster status\n{}", currentMetrics);
      reportMissingRegionServers(currentMetrics);
      reportNewRegionServers(currentMetrics);
    }
  
    /**
     * Build a set of all the host:port pairs of region servers known to this cluster.
     */
    private static Set<Address> collectKnownRegionServers(final ClusterStatus clusterStatus) {
      final Set<Address> regionServers = new HashSet<>();
      final Set<ServerName> serverNames = new HashSet<>(clusterStatus.getLiveServersLoad().keySet());
      serverNames.addAll(clusterStatus.getDeadServerNames());
  
      for (final ServerName serverName : serverNames) {
        regionServers.add(serverName.getAddress());
      }
      return Collections.unmodifiableSet(regionServers);
    }
  
    private void reportMissingRegionServers(final ClusterStatus clusterStatus) {
      final Set<Address> regionServers = collectKnownRegionServers(clusterStatus);
      final Set<Address> missingRegionServers = new HashSet<>(initialRegionServers);
      missingRegionServers.removeAll(regionServers);
      if (!missingRegionServers.isEmpty()) {
        final StringBuilder stringBuilder = new StringBuilder()
          .append("region server(s) are missing from this cluster report");
        final List<Address> sortedAddresses = new ArrayList<>(missingRegionServers);
        Collections.sort(sortedAddresses);
        for (final Address address : sortedAddresses) {
          stringBuilder.append("\n  ").append(address);
        }
        getLogger().warn(stringBuilder.toString());
      }
    }
  
    private void reportNewRegionServers(final ClusterStatus clusterStatus) {
      final Set<Address> regionServers = collectKnownRegionServers(clusterStatus);
      final Set<Address> newRegionServers = new HashSet<>(regionServers);
      newRegionServers.removeAll(initialRegionServers);
      if (!newRegionServers.isEmpty()) {
        final StringBuilder stringBuilder = new StringBuilder()
          .append("region server(s) are new for this cluster report");
        final List<Address> sortedAddresses = new ArrayList<>(newRegionServers);
        Collections.sort(sortedAddresses);
       for (final Address address : sortedAddresses) {
         stringBuilder.append("\n  ").append(address);
       }
       getLogger().warn(stringBuilder.toString());
     }
   }
 }