/*
    * 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 org.apache.logging.log4j.LogManager;
  import org.apache.logging.log4j.Logger;
  import org.codelibs.core.timer.TimeoutTarget;
  import org.codelibs.fess.helper.SystemHelper;
  import org.codelibs.fess.opensearch.client.SearchEngineClient;
  import org.codelibs.fess.util.ComponentUtil;
  import org.opensearch.action.admin.cluster.node.stats.NodeStats;
  import org.opensearch.action.admin.cluster.node.stats.NodesStatsResponse;
  import org.opensearch.monitor.os.OsStats;
  
  /**
   * Timeout target that periodically monitors search engine CPU usage.
   */
  public class LoadControlMonitorTarget implements TimeoutTarget {
  
      private static final Logger logger = LogManager.getLogger(LoadControlMonitorTarget.class);
  
      private final SystemHelper systemHelper;
  
      private int consecutiveFailures = 0;
  
      /**
       * Constructs a new load control monitor target.
       *
       * @param systemHelper the system helper to update with CPU usage
       */
      public LoadControlMonitorTarget(final SystemHelper systemHelper) {
          this.systemHelper = systemHelper;
      }
  
      @Override
      public void expired() {
          try {
              final SearchEngineClient client = ComponentUtil.getSearchEngineClient();
              final NodesStatsResponse response = client.admin().cluster().prepareNodesStats().addMetric("os").execute().actionGet(10000L);
  
              short maxCpu = 0;
              for (final NodeStats nodeStats : response.getNodes()) {
                  final OsStats os = nodeStats.getOs();
                  if (os != null && os.getCpu() != null) {
                      final short percent = os.getCpu().getPercent();
                      if (percent > maxCpu) {
                          maxCpu = percent;
                      }
                  }
              }
              systemHelper.setSearchEngineCpuPercent(maxCpu);
              consecutiveFailures = 0;
              if (logger.isDebugEnabled()) {
                  logger.debug("Search Engine CPU: {}%", maxCpu);
              }
          } catch (final Exception e) {
              systemHelper.setSearchEngineCpuPercent((short) 0);
              consecutiveFailures++;
              if (consecutiveFailures <= 3) {
                  logger.warn("Failed to get search engine CPU stats: {}", e.getMessage(), e);
              } else if (logger.isDebugEnabled()) {
                  logger.debug("Failed to get search engine CPU stats: {}", e.getMessage(), e);
              }
          }
      }
  }