/*
    * Copyright 2012-2025 CodeLibs Project and the Others.
    *
    * Licensed 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.codelibs.fess.timer;
  
  import java.util.stream.Collectors;
  
  import org.apache.commons.text.StringEscapeUtils;
  import org.apache.logging.log4j.LogManager;
  import org.apache.logging.log4j.Logger;
  import org.codelibs.fess.Constants;
  import org.codelibs.fess.mylasta.direction.FessConfig;
  import org.codelibs.fess.opensearch.client.SearchEngineClient;
  import org.codelibs.fess.util.ComponentUtil;
  import org.opensearch.action.admin.cluster.node.hotthreads.NodesHotThreadsResponse;
  import org.opensearch.common.unit.TimeValue;
  
  /**
   * Monitor target for tracking hot threads in the OpenSearch cluster.
   * This class extends MonitorTarget to provide monitoring functionality for
   * hot threads, which helps identify performance bottlenecks and resource
   * usage issues in the search engine cluster.
   */
  public class HotThreadMonitorTarget extends MonitorTarget {
      private static final Logger logger = LogManager.getLogger(HotThreadMonitorTarget.class);
  
      /**
       * Default constructor for HotThreadMonitorTarget.
       */
      public HotThreadMonitorTarget() {
          super();
      }
  
      @Override
      public void expired() {
          final StringBuilder buf = new StringBuilder(1000);
  
          buf.append("[HOTTHREAD MONITOR] ");
  
          final FessConfig fessConfig = ComponentUtil.getFessConfig();
  
          buf.append('{');
  
          final boolean ignoreIdleThreads = Constants.TRUE.equalsIgnoreCase(fessConfig.getCrawlerHotthreadIgnoreIdleThreads());
          final TimeValue interval = TimeValue.parseTimeValue(fessConfig.getCrawlerHotthreadInterval(), "crawler.hotthread.interval");
          final int threads = fessConfig.getCrawlerHotthreadThreadsAsInteger();
          final String timeout = fessConfig.getCrawlerHotthreadTimeout();
          final String type = fessConfig.getCrawlerHotthreadType();
          try {
              final SearchEngineClient esClient = ComponentUtil.getSearchEngineClient();
              final NodesHotThreadsResponse response = esClient.admin()
                      .cluster()
                      .prepareNodesHotThreads()
                      .setIgnoreIdleThreads(ignoreIdleThreads)
                      .setInterval(interval)
                      .setThreads(threads)
                      .setTimeout(timeout)
                      .setType(type)
                      .execute()
                      .actionGet(timeout);
              append(buf, "cluster_name", () -> response.getClusterName().value()).append(',');
              final String hotThreads = response.getNodesMap().entrySet().stream().map(e -> {
                  final StringBuilder tempBuf = new StringBuilder();
                  append(tempBuf, StringEscapeUtils.escapeJson(e.getKey()), () -> StringEscapeUtils.escapeJson(e.getValue().getHotThreads()));
                  return tempBuf.toString();
              }).collect(Collectors.joining(","));
              buf.append(hotThreads).append(',');
          } catch (final Exception e) {
              appendException(buf, e).append(',');
          }
  
          appendTimestamp(buf);
          buf.append('}');
  
          if (logger.isInfoEnabled()) {
              logger.info(buf.toString());
          }
      }
  
  }