/**
    * 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.master;
  
  import java.lang.Thread.UncaughtExceptionHandler;
  import java.util.ArrayList;
  import java.util.HashSet;
  import java.util.List;
  import java.util.Map;
  import java.util.Set;
  import java.util.concurrent.ConcurrentHashMap;
  import java.util.concurrent.ExecutorService;
  import java.util.concurrent.TimeUnit;
  
  import org.apache.commons.logging.Log;
  import org.apache.commons.logging.LogFactory;
  import org.apache.hadoop.hbase.classification.InterfaceAudience;
  import org.apache.hadoop.conf.Configuration;
  import org.apache.hadoop.hbase.HRegionInfo;
  import org.apache.hadoop.hbase.Server;
  import org.apache.hadoop.hbase.ServerName;
  
  /**
   * Run bulk assign.  Does one RCP per regionserver passing a
   * batch of regions using {@link GeneralBulkAssigner.SingleServerBulkAssigner}.
   */
  @InterfaceAudience.Private
  public class GeneralBulkAssigner extends BulkAssigner {
    private static final Log LOG = LogFactory.getLog(GeneralBulkAssigner.class);
  
    private Map<ServerName, List<HRegionInfo>> failedPlans
      = new ConcurrentHashMap<ServerName, List<HRegionInfo>>();
    private ExecutorService pool;
  
    final Map<ServerName, List<HRegionInfo>> bulkPlan;
    final AssignmentManager assignmentManager;
    final boolean waitTillAllAssigned;
  
    public GeneralBulkAssigner(final Server server,
        final Map<ServerName, List<HRegionInfo>> bulkPlan,
        final AssignmentManager am, final boolean waitTillAllAssigned) {
      super(server);
      this.bulkPlan = bulkPlan;
      this.assignmentManager = am;
      this.waitTillAllAssigned = waitTillAllAssigned;
    }
  
    @Override
    protected String getThreadNamePrefix() {
      return this.server.getServerName() + "-GeneralBulkAssigner";
    }
  
    @Override
    protected void populatePool(ExecutorService pool) {
      this.pool = pool; // shut it down later in case some assigner hangs
      for (Map.Entry<ServerName, List<HRegionInfo>> e: this.bulkPlan.entrySet()) {
        pool.execute(new SingleServerBulkAssigner(e.getKey(), e.getValue(),
          this.assignmentManager, this.failedPlans));
      }
    }
  
    /**
     *
     * @param timeout How long to wait.
     * @return true if done.
     */
    @Override
    protected boolean waitUntilDone(final long timeout)
    throws InterruptedException {
      Set<HRegionInfo> regionSet = new HashSet<HRegionInfo>();
      for (List<HRegionInfo> regionList : bulkPlan.values()) {
        regionSet.addAll(regionList);
      }
  
      pool.shutdown(); // no more task allowed
      int serverCount = bulkPlan.size();
      int regionCount = regionSet.size();
      long startTime = System.currentTimeMillis();
      long rpcWaitTime = startTime + timeout;
      while (!server.isStopped() && !pool.isTerminated()
          && rpcWaitTime > System.currentTimeMillis()) {
        if (failedPlans.isEmpty()) {
          pool.awaitTermination(100, TimeUnit.MILLISECONDS);
        } else {
         reassignFailedPlans();
       }
     }
     if (!pool.isTerminated()) {
       LOG.warn("bulk assigner is still running after "
         + (System.currentTimeMillis() - startTime) + "ms, shut it down now");
       // some assigner hangs, can't wait any more, shutdown the pool now
       List<Runnable> notStarted = pool.shutdownNow();
       if (notStarted != null && !notStarted.isEmpty()) {
         server.abort("some single server assigner hasn't started yet"
           + " when the bulk assigner timed out", null);
         return false;
       }
     }
 
     int reassigningRegions = 0;
     if (!failedPlans.isEmpty() && !server.isStopped()) {
       reassigningRegions = reassignFailedPlans();
     }
     assignmentManager.waitForAssignment(regionSet, waitTillAllAssigned,
       reassigningRegions, Math.max(System.currentTimeMillis(), rpcWaitTime));
 
     if (LOG.isDebugEnabled()) {
       long elapsedTime = System.currentTimeMillis() - startTime;
       String status = "successfully";
       if (!regionSet.isEmpty()) {
         status = "with " + regionSet.size() + " regions still in transition";
       }
       LOG.debug("bulk assigning total " + regionCount + " regions to "
         + serverCount + " servers, took " + elapsedTime + "ms, " + status);
     }
     return regionSet.isEmpty();
   }
 
   @Override
   protected long getTimeoutOnRIT() {
     // Guess timeout.  Multiply the max number of regions on a server
     // by how long we think one region takes opening.
     Configuration conf = server.getConfiguration();
     long perRegionOpenTimeGuesstimate =
       conf.getLong("hbase.bulk.assignment.perregion.open.time", 1000);
     int maxRegionsPerServer = 1;
     for (List<HRegionInfo> regionList : bulkPlan.values()) {
       int size = regionList.size();
       if (size > maxRegionsPerServer) {
         maxRegionsPerServer = size;
       }
     }
     long timeout = perRegionOpenTimeGuesstimate * maxRegionsPerServer
       + conf.getLong("hbase.regionserver.rpc.startup.waittime", 60000)
       + conf.getLong("hbase.bulk.assignment.perregionserver.rpc.waittime",
         30000) * bulkPlan.size();
     LOG.debug("Timeout-on-RIT=" + timeout);
     return timeout;
   }
 
   @Override
   protected UncaughtExceptionHandler getUncaughtExceptionHandler() {
     return new UncaughtExceptionHandler() {
       @Override
       public void uncaughtException(Thread t, Throwable e) {
         LOG.warn("Assigning regions in " + t.getName(), e);
       }
     };
   }
 
   private int reassignFailedPlans() {
     List<HRegionInfo> reassigningRegions = new ArrayList<HRegionInfo>();
     for (Map.Entry<ServerName, List<HRegionInfo>> e : failedPlans.entrySet()) {
       LOG.info("Failed assigning " + e.getValue().size()
           + " regions to server " + e.getKey() + ", reassigning them");
       reassigningRegions.addAll(failedPlans.remove(e.getKey()));
     }
     RegionStates regionStates = assignmentManager.getRegionStates();
     for (HRegionInfo region : reassigningRegions) {
       if (!regionStates.isRegionOnline(region)) {
         assignmentManager.invokeAssign(region);
       }
     }
     return reassigningRegions.size();
   }
 
   /**
    * Manage bulk assigning to a server.
    */
   static class SingleServerBulkAssigner implements Runnable {
     private final ServerName regionserver;
     private final List<HRegionInfo> regions;
     private final AssignmentManager assignmentManager;
     private final Map<ServerName, List<HRegionInfo>> failedPlans;
 
     SingleServerBulkAssigner(final ServerName regionserver,
         final List<HRegionInfo> regions, final AssignmentManager am,
         final Map<ServerName, List<HRegionInfo>> failedPlans) {
       this.regionserver = regionserver;
       this.regions = regions;
       this.assignmentManager = am;
       this.failedPlans = failedPlans;
     }
 
     @Override
     public void run() {
       try {
        if (!assignmentManager.assign(regionserver, regions)) {
          failedPlans.put(regionserver, regions);
        }
       } catch (Throwable t) {
         LOG.warn("Failed bulking assigning " + regions.size()
             + " region(s) to " + regionserver.getServerName()
             + ", and continue to bulk assign others", t);
         failedPlans.put(regionserver, regions);
       }
     }
   }
 }