/**
 * 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.janitor;

import static org.junit.Assert.assertFalse;
import static org.junit.Assert.assertNotNull;
import static org.junit.Assert.assertTrue;

import java.io.IOException;
import java.util.ArrayList;
import java.util.List;
import java.util.concurrent.ExecutionException;
import org.apache.hadoop.hbase.HBaseClassTestRule;
import org.apache.hadoop.hbase.HBaseTestingUtility;
import org.apache.hadoop.hbase.HRegionLocation;
import org.apache.hadoop.hbase.MetaMockingUtil;
import org.apache.hadoop.hbase.MetaTableAccessor;
import org.apache.hadoop.hbase.TableName;
import org.apache.hadoop.hbase.TableNameTestRule;
import org.apache.hadoop.hbase.client.Admin;
import org.apache.hadoop.hbase.client.Connection;
import org.apache.hadoop.hbase.client.ConnectionFactory;
import org.apache.hadoop.hbase.client.Get;
import org.apache.hadoop.hbase.client.RegionInfo;
import org.apache.hadoop.hbase.client.RegionLocator;
import org.apache.hadoop.hbase.client.Result;
import org.apache.hadoop.hbase.client.Table;
import org.apache.hadoop.hbase.master.HMaster;
import org.apache.hadoop.hbase.master.ServerManager;
import org.apache.hadoop.hbase.master.assignment.AssignmentManager;
import org.apache.hadoop.hbase.testclassification.MasterTests;
import org.apache.hadoop.hbase.testclassification.MediumTests;
import org.apache.hadoop.hbase.util.Bytes;
import org.apache.hadoop.hbase.util.PairOfSameType;
import org.apache.hadoop.hbase.util.Threads;
import org.junit.AfterClass;
import org.junit.BeforeClass;
import org.junit.ClassRule;
import org.junit.Rule;
import org.junit.Test;
import org.junit.experimental.categories.Category;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

@Category({ MasterTests.class, MediumTests.class })
public class TestCatalogJanitorInMemoryStates {

  @ClassRule
  public static final HBaseClassTestRule CLASS_RULE =
    HBaseClassTestRule.forClass(TestCatalogJanitorInMemoryStates.class);

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

  private static final HBaseTestingUtility TEST_UTIL = new HBaseTestingUtility();

  private static byte[] FAMILY = Bytes.toBytes("testFamily");

  @Rule
  public final TableNameTestRule name = new TableNameTestRule();

  @BeforeClass
  public static void setUpBeforeClass() throws Exception {
    TEST_UTIL.startMiniCluster(1);
  }

  @AfterClass
  public static void tearDownAfterClass() throws Exception {
    TEST_UTIL.shutdownMiniCluster();
  }

  /**
   * Test clearing a split parent from memory.
   */
  @Test
  public void testInMemoryParentCleanup()
    throws IOException, InterruptedException, ExecutionException {
    HMaster master = TEST_UTIL.getHBaseCluster().getMaster();
    final AssignmentManager am = master.getAssignmentManager();
    final ServerManager sm = master.getServerManager();

    Admin admin = TEST_UTIL.getAdmin();
    admin.enableCatalogJanitor(false);

    final TableName tableName = name.getTableName();
    Table t = TEST_UTIL.createTable(tableName, FAMILY);
    TEST_UTIL.loadTable(t, FAMILY, false);

    RegionLocator locator = TEST_UTIL.getConnection().getRegionLocator(tableName);
    List<HRegionLocation> allRegionLocations = locator.getAllRegionLocations();

    // We need to create a valid split with daughter regions
    HRegionLocation parent = allRegionLocations.get(0);
    List<HRegionLocation> daughters = splitRegion(parent.getRegionInfo());
    LOG.info("Parent region: " + parent);
    LOG.info("Daughter regions: " + daughters);
    assertNotNull("Should have found daughter regions for " + parent, daughters);

    assertTrue("Parent region should exist in RegionStates",
      am.getRegionStates().isRegionInRegionStates(parent.getRegion()));
    assertTrue("Parent region should exist in ServerManager",
      sm.isRegionInServerManagerStates(parent.getRegion()));

    // clean the parent
    Result r = MetaMockingUtil.getMetaTableRowResult(parent.getRegion(), null,
      daughters.get(0).getRegion(), daughters.get(1).getRegion());
    CatalogJanitor.cleanParent(master, parent.getRegion(), r);
    assertFalse("Parent region should have been removed from RegionStates",
      am.getRegionStates().isRegionInRegionStates(parent.getRegion()));
    assertFalse("Parent region should have been removed from ServerManager",
      sm.isRegionInServerManagerStates(parent.getRegion()));

  }

  /**
   * Splits a region
   * @param r Region to split.
   * @return List of region locations
   */
  private List<HRegionLocation> splitRegion(final RegionInfo r)
    throws IOException, InterruptedException, ExecutionException {
    List<HRegionLocation> locations = new ArrayList<>();
    // Split this table in two.
    Admin admin = TEST_UTIL.getAdmin();
    Connection connection = TEST_UTIL.getConnection();
    admin.splitRegionAsync(r.getEncodedNameAsBytes()).get();
    admin.close();
    PairOfSameType<RegionInfo> regions = waitOnDaughters(r);
    if (regions != null) {
      try (RegionLocator rl = connection.getRegionLocator(r.getTable())) {
        locations.add(rl.getRegionLocation(regions.getFirst().getEncodedNameAsBytes()));
        locations.add(rl.getRegionLocation(regions.getSecond().getEncodedNameAsBytes()));
      }
      return locations;
    }
    return locations;
  }

  /*
   * Wait on region split. May return because we waited long enough on the split and it didn't
   * happen. Caller should check.
   * @param r
   * @return Daughter regions; caller needs to check table actually split.
   */
  private PairOfSameType<RegionInfo> waitOnDaughters(final RegionInfo r) throws IOException {
    long start = System.currentTimeMillis();
    PairOfSameType<RegionInfo> pair = null;
    try (Connection conn = ConnectionFactory.createConnection(TEST_UTIL.getConfiguration());
      Table metaTable = conn.getTable(TableName.META_TABLE_NAME)) {
      Result result = null;
      RegionInfo region = null;
      while ((System.currentTimeMillis() - start) < 60000) {
        result = metaTable.get(new Get(r.getRegionName()));
        if (result == null) {
          break;
        }
        region = MetaTableAccessor.getRegionInfo(result);
        if (region.isSplitParent()) {
          LOG.debug(region.toString() + " IS a parent!");
          pair = MetaTableAccessor.getDaughterRegions(result);
          break;
        }
        Threads.sleep(100);
      }

      if (pair.getFirst() == null || pair.getSecond() == null) {
        throw new IOException("Failed to get daughters, for parent region: " + r);
      }
      return pair;
    }
  }
}
