/**
 * 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.balancer;

import static org.apache.hadoop.hbase.favored.FavoredNodeAssignmentHelper.FAVORED_NODES_NUM;
import static org.junit.Assert.assertFalse;
import static org.junit.Assert.assertNotNull;
import static org.junit.Assert.assertEquals;

import java.util.List;
import java.util.Set;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.hbase.HBaseTestingUtility;
import org.apache.hadoop.hbase.HColumnDescriptor;
import org.apache.hadoop.hbase.HConstants;
import org.apache.hadoop.hbase.HRegionInfo;
import org.apache.hadoop.hbase.HTableDescriptor;
import org.apache.hadoop.hbase.ServerName;
import org.apache.hadoop.hbase.TableName;
import org.apache.hadoop.hbase.client.Admin;
import org.apache.hadoop.hbase.favored.FavoredNodesManager;
import org.apache.hadoop.hbase.testclassification.MediumTests;
import org.apache.hadoop.hbase.util.Bytes;
import org.apache.hadoop.hbase.util.Threads;

import com.google.common.collect.Sets;
import org.junit.After;
import org.junit.Test;
import org.junit.experimental.categories.Category;

/*
 * This case tests a scenario when a cluster with tables is moved from Stochastic Load Balancer
 * to FavoredStochasticLoadBalancer and the generation of favored nodes after switch.
 */
@Category(MediumTests.class)
public class TestFavoredNodeTableImport {

  private static final Log LOG = LogFactory.getLog(TestFavoredNodeTableImport.class);

  private static final int SLAVES = 3;
  private static final int REGION_NUM = 20;
  private static final HBaseTestingUtility UTIL = new HBaseTestingUtility();
  private static final Configuration conf = UTIL.getConfiguration();

  @After
  public void stopCluster() throws Exception {
    UTIL.cleanupTestDir();
    UTIL.shutdownMiniCluster();
  }

  @Test
  public void testTableCreation() throws Exception {

    conf.set(HConstants.HBASE_MASTER_LOADBALANCER_CLASS, StochasticLoadBalancer.class.getName());

    LOG.info("Starting up cluster");
    UTIL.startMiniCluster(SLAVES);
    while (!UTIL.getMiniHBaseCluster().getMaster().isInitialized()) {
      Threads.sleep(1);
    }
    Admin admin = UTIL.getAdmin();
    admin.setBalancerRunning(false, true);

    String tableName = "testFNImport";
    HTableDescriptor desc = new HTableDescriptor(TableName.valueOf(tableName));
    desc.addFamily(new HColumnDescriptor(HConstants.CATALOG_FAMILY));
    admin.createTable(desc, Bytes.toBytes("a"), Bytes.toBytes("z"), REGION_NUM);
    UTIL.waitTableAvailable(desc.getTableName());

    LOG.info("Shutting down cluster");
    UTIL.shutdownMiniHBaseCluster();

    Thread.sleep(2000);
    LOG.info("Starting cluster again with FN Balancer");
    UTIL.getConfiguration().set(HConstants.HBASE_MASTER_LOADBALANCER_CLASS,
        FavoredStochasticBalancer.class.getName());
    UTIL.restartHBaseCluster(SLAVES);
    while (!UTIL.getMiniHBaseCluster().getMaster().isInitialized()) {
      Threads.sleep(1);
    }
    admin = UTIL.getAdmin();

    UTIL.waitTableAvailable(desc.getTableName());

    FavoredNodesManager fnm = UTIL.getHBaseCluster().getMaster().getFavoredNodesManager();

    List<HRegionInfo> regionsOfTable = admin.getTableRegions(TableName.valueOf(tableName));
    for (HRegionInfo rInfo : regionsOfTable) {
      Set<ServerName> favNodes = Sets.newHashSet(fnm.getFavoredNodes(rInfo));
      assertNotNull(favNodes);
      assertEquals("Required no of favored nodes not found.", FAVORED_NODES_NUM, favNodes.size());
      for (ServerName fn : favNodes) {
        assertEquals("StartCode invalid for:" + fn, ServerName.NON_STARTCODE, fn.getStartcode());
      }
    }
  }
}