package org.apache.helix.controller.stages;

/*
 * 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.
 */

import java.util.Collection;
import java.util.HashSet;
import java.util.List;
import java.util.Map;
import java.util.Set;
import java.util.concurrent.Callable;

import com.google.common.collect.Maps;
import com.google.common.collect.Sets;
import org.apache.helix.HelixDataAccessor;
import org.apache.helix.HelixManager;
import org.apache.helix.controller.LogUtil;
import org.apache.helix.controller.dataproviders.BaseControllerDataProvider;
import org.apache.helix.controller.dataproviders.ResourceControllerDataProvider;
import org.apache.helix.controller.dataproviders.WorkflowControllerDataProvider;
import org.apache.helix.controller.pipeline.AbstractBaseStage;
import org.apache.helix.controller.pipeline.StageException;
import org.apache.helix.model.ClusterConfig;
import org.apache.helix.model.InstanceConfig;
import org.apache.helix.model.LiveInstance;
import org.apache.helix.model.Message;
import org.apache.helix.monitoring.mbeans.ClusterStatusMonitor;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

public class ReadClusterDataStage extends AbstractBaseStage {
  private static final Logger logger = LoggerFactory.getLogger(ReadClusterDataStage.class.getName());

  @Override
  public void process(ClusterEvent event) throws Exception {
    _eventId = event.getEventId();
    HelixManager manager = event.getAttribute(AttributeName.helixmanager.name());
    if (manager == null) {
      throw new StageException("HelixManager attribute value is null");
    }

    final BaseControllerDataProvider dataProvider =
        event.getAttribute(AttributeName.ControllerDataProvider.name());

    HelixDataAccessor dataAccessor = manager.getHelixDataAccessor();

    dataProvider.refresh(dataAccessor);
    final ClusterConfig clusterConfig = dataProvider.getClusterConfig();
        final ClusterStatusMonitor clusterStatusMonitor =
            event.getAttribute(AttributeName.clusterStatusMonitor.name());

    // TODO (harry): move this to separate stage for resource controller only
    if (dataProvider instanceof ResourceControllerDataProvider) {
      asyncExecute(dataProvider.getAsyncTasksThreadPool(), new Callable<Object>() {
        @Override public Object call() {
          // Update the cluster status gauges
          if (clusterStatusMonitor != null) {
            LogUtil.logDebug(logger, _eventId, "Update cluster status monitors");

            Set<String> instanceSet = Sets.newHashSet();
            Set<String> liveInstanceSet = Sets.newHashSet();
            Set<String> disabledInstanceSet = Sets.newHashSet();
            Map<String, Map<String, List<String>>> disabledPartitions = Maps.newHashMap();
            Map<String, List<String>> oldDisabledPartitions = Maps.newHashMap();
            Map<String, Set<String>> tags = Maps.newHashMap();
            Map<String, LiveInstance> liveInstanceMap = dataProvider.getLiveInstances();
            Map<String, Set<Message>> instanceMessageMap = Maps.newHashMap();
            for (Map.Entry<String, InstanceConfig> e : dataProvider.getInstanceConfigMap()
                .entrySet()) {
              String instanceName = e.getKey();
              InstanceConfig config = e.getValue();
              instanceSet.add(instanceName);
              if (liveInstanceMap.containsKey(instanceName)) {
                liveInstanceSet.add(instanceName);
                instanceMessageMap.put(instanceName,
                    Sets.newHashSet(dataProvider.getMessages(instanceName).values()));
              }
              if (!config.getInstanceEnabled() || (clusterConfig.getDisabledInstances() != null
                  && clusterConfig.getDisabledInstances().containsKey(instanceName))) {
                disabledInstanceSet.add(instanceName);
              }

              // TODO : Get rid of this data structure once the API is removed.
              oldDisabledPartitions.put(instanceName, config.getDisabledPartitions());
              disabledPartitions.put(instanceName, config.getDisabledPartitionsMap());

              Set<String> instanceTags = Sets.newHashSet(config.getTags());
              tags.put(instanceName, instanceTags);
            }
            clusterStatusMonitor
                .setClusterInstanceStatus(liveInstanceSet, instanceSet, disabledInstanceSet,
                    disabledPartitions, oldDisabledPartitions, tags, instanceMessageMap);
            LogUtil.logDebug(logger, _eventId, "Complete cluster status monitors update.");
          }
          return null;
        }
      });
    } else {
      asyncExecute(dataProvider.getAsyncTasksThreadPool(), new Callable<Object>() {
        @Override
        public Object call() {
          clusterStatusMonitor.refreshWorkflowsStatus((WorkflowControllerDataProvider) dataProvider);
          clusterStatusMonitor.refreshJobsStatus((WorkflowControllerDataProvider) dataProvider);
          LogUtil.logDebug(logger, _eventId, "Workflow/Job gauge status successfully refreshed");
          return null;
        }
      });
    }
  }
}