/*
 * 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.jupiter.api.Assertions.assertEquals;
import static org.junit.jupiter.api.Assertions.assertNotNull;
import static org.junit.jupiter.api.Assertions.assertTrue;

import java.util.List;
import java.util.Set;
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.master.HMaster;
import org.apache.hadoop.hbase.testclassification.MediumTests;
import org.apache.hadoop.hbase.util.Bytes;
import org.apache.hadoop.hbase.util.Threads;
import org.junit.jupiter.api.AfterEach;
import org.junit.jupiter.api.Tag;
import org.junit.jupiter.api.Test;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import org.apache.hbase.thirdparty.com.google.common.collect.Sets;

/*
 * 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.
 */
@Tag(MediumTests.TAG)
public class TestFavoredNodeTableImport {

  private static final Logger LOG = LoggerFactory.getLogger(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();

  @AfterEach
  public void stopCluster() throws Exception {
    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.balancerSwitch(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());
    admin.balancerSwitch(true, true);

    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);
    HMaster master = UTIL.getMiniHBaseCluster().getMaster();
    while (!master.isInitialized()) {
      Threads.sleep(1);
    }
    UTIL.waitTableAvailable(desc.getTableName());
    UTIL.waitUntilNoRegionsInTransition(10000);
    assertTrue(master.isBalancerOn());

    FavoredNodesManager fnm = master.getFavoredNodesManager();
    assertNotNull(fnm);

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