/*
 * 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;

import static org.junit.Assert.assertEquals;
import static org.junit.Assert.assertNotNull;
import static org.junit.Assert.assertNull;
import static org.junit.Assert.assertTrue;
import static org.mockito.ArgumentMatchers.any;
import static org.mockito.Mockito.doReturn;
import static org.mockito.Mockito.mock;
import static org.mockito.Mockito.reset;
import static org.mockito.Mockito.times;
import static org.mockito.Mockito.verify;

import java.io.IOException;
import java.util.Collections;
import java.util.List;
import java.util.Random;
import java.util.concurrent.ThreadLocalRandom;
import org.apache.hadoop.conf.Configuration;
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.RegionInfoBuilder;
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.ipc.CallRunner;
import org.apache.hadoop.hbase.ipc.DelegatingRpcScheduler;
import org.apache.hadoop.hbase.ipc.PriorityFunction;
import org.apache.hadoop.hbase.ipc.RpcScheduler;
import org.apache.hadoop.hbase.master.HMaster;
import org.apache.hadoop.hbase.regionserver.HRegion;
import org.apache.hadoop.hbase.regionserver.HRegionServer;
import org.apache.hadoop.hbase.regionserver.SimpleRpcSchedulerFactory;
import org.apache.hadoop.hbase.testclassification.MediumTests;
import org.apache.hadoop.hbase.testclassification.MiscTests;
import org.apache.hadoop.hbase.util.Bytes;
import org.apache.hadoop.hbase.util.EnvironmentEdgeManager;
import org.apache.hadoop.hbase.util.Pair;
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.junit.rules.TestName;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

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

/**
 * Test {@link org.apache.hadoop.hbase.MetaTableAccessor}.
 */
@Category({ MiscTests.class, MediumTests.class })
@SuppressWarnings("deprecation")
public class TestMetaTableAccessor {
  @ClassRule
  public static final HBaseClassTestRule CLASS_RULE =
    HBaseClassTestRule.forClass(TestMetaTableAccessor.class);

  private static final Logger LOG = LoggerFactory.getLogger(TestMetaTableAccessor.class);
  private static final HBaseTestingUtil UTIL = new HBaseTestingUtil();
  private static Connection connection;

  @Rule
  public TestName name = new TestName();

  @BeforeClass
  public static void beforeClass() throws Exception {
    UTIL.startMiniCluster(3);

    Configuration c = new Configuration(UTIL.getConfiguration());
    // Tests to 4 retries every 5 seconds. Make it try every 1 second so more
    // responsive. 1 second is default as is ten retries.
    c.setLong("hbase.client.pause", 1000);
    c.setInt(HConstants.HBASE_CLIENT_RETRIES_NUMBER, 10);
    connection = ConnectionFactory.createConnection(c);
  }

  @AfterClass
  public static void afterClass() throws Exception {
    connection.close();
    UTIL.shutdownMiniCluster();
  }

  @Test
  public void testIsMetaWhenAllHealthy() throws InterruptedException {
    HMaster m = UTIL.getMiniHBaseCluster().getMaster();
    assertTrue(m.waitForMetaOnline());
  }

  @Test
  public void testIsMetaWhenMetaGoesOffline() throws InterruptedException {
    HMaster m = UTIL.getMiniHBaseCluster().getMaster();
    int index = UTIL.getMiniHBaseCluster().getServerWithMeta();
    HRegionServer rsWithMeta = UTIL.getMiniHBaseCluster().getRegionServer(index);
    rsWithMeta.abort("TESTING");
    assertTrue(m.waitForMetaOnline());
  }

  /**
   * Does {@link MetaTableAccessor#getRegion(Connection, byte[])} and a write against hbase:meta
   * while its hosted server is restarted to prove our retrying works.
   */
  @Test
  public void testRetrying() throws IOException, InterruptedException {
    final TableName tableName = TableName.valueOf(name.getMethodName());
    LOG.info("Started " + tableName);
    Table t = UTIL.createMultiRegionTable(tableName, HConstants.CATALOG_FAMILY);
    int regionCount = -1;
    try (RegionLocator r = UTIL.getConnection().getRegionLocator(tableName)) {
      regionCount = r.getStartKeys().length;
    }
    // Test it works getting a region from just made user table.
    final List<RegionInfo> regions = testGettingTableRegions(connection, tableName, regionCount);
    MetaTask reader = new MetaTask(connection, "reader") {
      @Override
      void metaTask() throws Throwable {
        testGetRegion(connection, regions.get(0));
        LOG.info("Read " + regions.get(0).getEncodedName());
      }
    };
    MetaTask writer = new MetaTask(connection, "writer") {

      @Override
      void metaTask() throws IOException {
        MetaTableAccessor.addRegionsToMeta(connection, Collections.singletonList(regions.get(0)),
          1);
        LOG.info("Wrote " + regions.get(0).getEncodedName());
      }
    };
    reader.start();
    writer.start();

    // We're gonna check how it takes. If it takes too long, we will consider
    // it as a fail. We can't put that in the @Test tag as we want to close
    // the threads nicely
    final long timeOut = 180000;
    long startTime = EnvironmentEdgeManager.currentTime();

    try {
      // Make sure reader and writer are working.
      assertTrue(reader.isProgressing());
      assertTrue(writer.isProgressing());

      // Kill server hosting meta -- twice . See if our reader/writer ride over the
      // meta moves. They'll need to retry.
      for (int i = 0; i < 2; i++) {
        LOG.info("Restart=" + i);
        UTIL.ensureSomeRegionServersAvailable(2);
        int index = -1;
        do {
          index = UTIL.getMiniHBaseCluster().getServerWithMeta();
        } while (index == -1 && startTime + timeOut < EnvironmentEdgeManager.currentTime());

        if (index != -1) {
          UTIL.getMiniHBaseCluster().abortRegionServer(index);
          UTIL.getMiniHBaseCluster().waitOnRegionServer(index);
        }
      }

      assertTrue("reader: " + reader.toString(), reader.isProgressing());
      assertTrue("writer: " + writer.toString(), writer.isProgressing());
    } catch (IOException e) {
      throw e;
    } finally {
      reader.stop = true;
      writer.stop = true;
      reader.join();
      writer.join();
      t.close();
    }
    long exeTime = EnvironmentEdgeManager.currentTime() - startTime;
    assertTrue("Timeout: test took " + exeTime / 1000 + " sec", exeTime < timeOut);
  }

  /**
   * Thread that runs a MetaTableAccessor task until asked stop.
   */
  abstract static class MetaTask extends Thread {
    boolean stop = false;
    int count = 0;
    Throwable t = null;
    final Connection connection;

    MetaTask(final Connection connection, final String name) {
      super(name);
      this.connection = connection;
    }

    @Override
    public void run() {
      try {
        while (!this.stop) {
          LOG.info("Before " + this.getName() + ", count=" + this.count);
          metaTask();
          this.count += 1;
          LOG.info("After " + this.getName() + ", count=" + this.count);
          Thread.sleep(100);
        }
      } catch (Throwable t) {
        LOG.info(this.getName() + " failed", t);
        this.t = t;
      }
    }

    boolean isProgressing() throws InterruptedException {
      int currentCount = this.count;
      while (currentCount == this.count) {
        if (!isAlive()) return false;
        if (this.t != null) return false;
        Thread.sleep(10);
      }
      return true;
    }

    @Override
    public String toString() {
      return "count=" + this.count + ", t=" + (this.t == null ? "null" : this.t.toString());
    }

    abstract void metaTask() throws Throwable;
  }

  @Test
  public void testGetRegion() throws IOException, InterruptedException {
    final String name = this.name.getMethodName();
    LOG.info("Started " + name);
    // Test get on non-existent region.
    Pair<RegionInfo, ServerName> pair =
      MetaTableAccessor.getRegion(connection, Bytes.toBytes("nonexistent-region"));
    assertNull(pair);
    LOG.info("Finished " + name);
  }

  // Test for the optimization made in HBASE-3650
  @Test
  public void testScanMetaForTable() throws IOException, InterruptedException {
    final TableName tableName = TableName.valueOf(name.getMethodName());
    LOG.info("Started " + tableName);

    /**
     * Create 2 tables - testScanMetaForTable - testScanMetaForTablf
     **/

    UTIL.createTable(tableName, HConstants.CATALOG_FAMILY);
    // name that is +1 greater than the first one (e+1=f)
    TableName greaterName = TableName.valueOf("testScanMetaForTablf");
    UTIL.createTable(greaterName, HConstants.CATALOG_FAMILY);

    // Now make sure we only get the regions from 1 of the tables at a time

    assertEquals(1, MetaTableAccessor.getTableRegions(connection, tableName).size());
    assertEquals(1, MetaTableAccessor.getTableRegions(connection, greaterName).size());
  }

  private static List<RegionInfo> testGettingTableRegions(final Connection connection,
    final TableName name, final int regionCount) throws IOException, InterruptedException {
    List<RegionInfo> regions = MetaTableAccessor.getTableRegions(connection, name);
    assertEquals(regionCount, regions.size());
    Pair<RegionInfo, ServerName> pair =
      MetaTableAccessor.getRegion(connection, regions.get(0).getRegionName());
    assertEquals(regions.get(0).getEncodedName(), pair.getFirst().getEncodedName());
    return regions;
  }

  private static void testGetRegion(final Connection connection, final RegionInfo region)
    throws IOException, InterruptedException {
    Pair<RegionInfo, ServerName> pair =
      MetaTableAccessor.getRegion(connection, region.getRegionName());
    assertEquals(region.getEncodedName(), pair.getFirst().getEncodedName());
  }

  @Test
  public void testMetaLocationsForRegionReplicas() throws IOException {
    Random rand = ThreadLocalRandom.current();

    ServerName serverName0 = ServerName.valueOf("foo", 60010, rand.nextLong());
    ServerName serverName1 = ServerName.valueOf("bar", 60010, rand.nextLong());
    ServerName serverName100 = ServerName.valueOf("baz", 60010, rand.nextLong());

    long regionId = EnvironmentEdgeManager.currentTime();
    RegionInfo primary = RegionInfoBuilder.newBuilder(TableName.valueOf(name.getMethodName()))
      .setStartKey(HConstants.EMPTY_START_ROW).setEndKey(HConstants.EMPTY_END_ROW).setSplit(false)
      .setRegionId(regionId).setReplicaId(0).build();
    RegionInfo replica1 = RegionInfoBuilder.newBuilder(TableName.valueOf(name.getMethodName()))
      .setStartKey(HConstants.EMPTY_START_ROW).setEndKey(HConstants.EMPTY_END_ROW).setSplit(false)
      .setRegionId(regionId).setReplicaId(1).build();
    RegionInfo replica100 = RegionInfoBuilder.newBuilder(TableName.valueOf(name.getMethodName()))
      .setStartKey(HConstants.EMPTY_START_ROW).setEndKey(HConstants.EMPTY_END_ROW).setSplit(false)
      .setRegionId(regionId).setReplicaId(100).build();

    long seqNum0 = rand.nextLong();
    long seqNum1 = rand.nextLong();
    long seqNum100 = rand.nextLong();

    try (Table meta = MetaTableAccessor.getMetaHTable(connection)) {
      MetaTableAccessor.updateRegionLocation(connection, primary, serverName0, seqNum0,
        EnvironmentEdgeManager.currentTime());

      // assert that the server, startcode and seqNum columns are there for the primary region
      assertMetaLocation(meta, primary.getRegionName(), serverName0, seqNum0, 0, true);

      // add replica = 1
      MetaTableAccessor.updateRegionLocation(connection, replica1, serverName1, seqNum1,
        EnvironmentEdgeManager.currentTime());
      // check whether the primary is still there
      assertMetaLocation(meta, primary.getRegionName(), serverName0, seqNum0, 0, true);
      // now check for replica 1
      assertMetaLocation(meta, primary.getRegionName(), serverName1, seqNum1, 1, true);

      // add replica = 1
      MetaTableAccessor.updateRegionLocation(connection, replica100, serverName100, seqNum100,
        EnvironmentEdgeManager.currentTime());
      // check whether the primary is still there
      assertMetaLocation(meta, primary.getRegionName(), serverName0, seqNum0, 0, true);
      // check whether the replica 1 is still there
      assertMetaLocation(meta, primary.getRegionName(), serverName1, seqNum1, 1, true);
      // now check for replica 1
      assertMetaLocation(meta, primary.getRegionName(), serverName100, seqNum100, 100, true);
    }
  }

  public static void assertMetaLocation(Table meta, byte[] row, ServerName serverName, long seqNum,
    int replicaId, boolean checkSeqNum) throws IOException {
    Get get = new Get(row);
    Result result = meta.get(get);
    assertTrue(Bytes.equals(
      result.getValue(HConstants.CATALOG_FAMILY, CatalogFamilyFormat.getServerColumn(replicaId)),
      Bytes.toBytes(serverName.getAddress().toString())));
    assertTrue(Bytes.equals(
      result.getValue(HConstants.CATALOG_FAMILY, CatalogFamilyFormat.getStartCodeColumn(replicaId)),
      Bytes.toBytes(serverName.getStartcode())));
    if (checkSeqNum) {
      assertTrue(Bytes.equals(
        result.getValue(HConstants.CATALOG_FAMILY, CatalogFamilyFormat.getSeqNumColumn(replicaId)),
        Bytes.toBytes(seqNum)));
    }
  }

  public static void assertEmptyMetaLocation(Table meta, byte[] row, int replicaId)
    throws IOException {
    Get get = new Get(row);
    Result result = meta.get(get);
    Cell serverCell = result.getColumnLatestCell(HConstants.CATALOG_FAMILY,
      CatalogFamilyFormat.getServerColumn(replicaId));
    Cell startCodeCell = result.getColumnLatestCell(HConstants.CATALOG_FAMILY,
      CatalogFamilyFormat.getStartCodeColumn(replicaId));
    assertNotNull(serverCell);
    assertNotNull(startCodeCell);
    assertEquals(0, serverCell.getValueLength());
    assertEquals(0, startCodeCell.getValueLength());
  }

  @Test
  public void testMetaLocationForRegionReplicasIsAddedAtTableCreation() throws IOException {
    long regionId = EnvironmentEdgeManager.currentTime();
    RegionInfo primary = RegionInfoBuilder.newBuilder(TableName.valueOf(name.getMethodName()))
      .setStartKey(HConstants.EMPTY_START_ROW).setEndKey(HConstants.EMPTY_END_ROW).setSplit(false)
      .setRegionId(regionId).setReplicaId(0).build();

    Table meta = MetaTableAccessor.getMetaHTable(connection);
    try {
      List<RegionInfo> regionInfos = Lists.newArrayList(primary);
      MetaTableAccessor.addRegionsToMeta(connection, regionInfos, 3);

      assertEmptyMetaLocation(meta, primary.getRegionName(), 1);
      assertEmptyMetaLocation(meta, primary.getRegionName(), 2);
    } finally {
      meta.close();
    }
  }

  @Test
  public void testMetaScanner() throws Exception {
    LOG.info("Starting " + name.getMethodName());

    final TableName tableName = TableName.valueOf(name.getMethodName());
    final byte[] FAMILY = Bytes.toBytes("family");
    final byte[][] SPLIT_KEYS =
      new byte[][] { Bytes.toBytes("region_a"), Bytes.toBytes("region_b") };

    UTIL.createTable(tableName, FAMILY, SPLIT_KEYS);
    Table table = connection.getTable(tableName);
    // Make sure all the regions are deployed
    HBaseTestingUtil.countRows(table);

    ClientMetaTableAccessor.Visitor visitor = mock(ClientMetaTableAccessor.Visitor.class);
    doReturn(true).when(visitor).visit(any());

    // Scanning the entire table should give us three rows
    MetaTableAccessor.scanMetaForTableRegions(connection, visitor, tableName);
    verify(visitor, times(3)).visit(any());

    // Scanning the table with a specified empty start row should also
    // give us three hbase:meta rows
    reset(visitor);
    doReturn(true).when(visitor).visit(any());
    MetaTableAccessor.scanMeta(connection, visitor, tableName, null, 1000);
    verify(visitor, times(3)).visit(any());

    // Scanning the table starting in the middle should give us two rows:
    // region_a and region_b
    reset(visitor);
    doReturn(true).when(visitor).visit(any());
    MetaTableAccessor.scanMeta(connection, visitor, tableName, Bytes.toBytes("region_ac"), 1000);
    verify(visitor, times(2)).visit(any());

    // Scanning with a limit of 1 should only give us one row
    reset(visitor);
    doReturn(true).when(visitor).visit(any());
    MetaTableAccessor.scanMeta(connection, visitor, tableName, Bytes.toBytes("region_ac"), 1);
    verify(visitor, times(1)).visit(any());
    table.close();
  }

  /**
   * Tests whether maximum of masters system time versus RSs local system time is used
   */
  @Test
  public void testMastersSystemTimeIsUsedInUpdateLocations() throws IOException {
    long regionId = EnvironmentEdgeManager.currentTime();
    RegionInfo regionInfo = RegionInfoBuilder.newBuilder(TableName.valueOf(name.getMethodName()))
      .setStartKey(HConstants.EMPTY_START_ROW).setEndKey(HConstants.EMPTY_END_ROW).setSplit(false)
      .setRegionId(regionId).setReplicaId(0).build();

    ServerName sn = ServerName.valueOf("bar", 0, 0);
    try (Table meta = MetaTableAccessor.getMetaHTable(connection)) {
      List<RegionInfo> regionInfos = Lists.newArrayList(regionInfo);
      MetaTableAccessor.addRegionsToMeta(connection, regionInfos, 1);

      long masterSystemTime = EnvironmentEdgeManager.currentTime() + 123456789;
      MetaTableAccessor.updateRegionLocation(connection, regionInfo, sn, 1, masterSystemTime);

      Get get = new Get(regionInfo.getRegionName());
      Result result = meta.get(get);
      Cell serverCell = result.getColumnLatestCell(HConstants.CATALOG_FAMILY,
        CatalogFamilyFormat.getServerColumn(0));
      Cell startCodeCell = result.getColumnLatestCell(HConstants.CATALOG_FAMILY,
        CatalogFamilyFormat.getStartCodeColumn(0));
      Cell seqNumCell = result.getColumnLatestCell(HConstants.CATALOG_FAMILY,
        CatalogFamilyFormat.getSeqNumColumn(0));
      assertNotNull(serverCell);
      assertNotNull(startCodeCell);
      assertNotNull(seqNumCell);
      assertTrue(serverCell.getValueLength() > 0);
      assertTrue(startCodeCell.getValueLength() > 0);
      assertTrue(seqNumCell.getValueLength() > 0);
      assertEquals(masterSystemTime, serverCell.getTimestamp());
      assertEquals(masterSystemTime, startCodeCell.getTimestamp());
      assertEquals(masterSystemTime, seqNumCell.getTimestamp());
    }
  }

  public static class SpyingRpcSchedulerFactory extends SimpleRpcSchedulerFactory {
    @Override
    public RpcScheduler create(Configuration conf, PriorityFunction priority, Abortable server) {
      final RpcScheduler delegate = super.create(conf, priority, server);
      return new SpyingRpcScheduler(delegate);
    }
  }

  public static class SpyingRpcScheduler extends DelegatingRpcScheduler {
    long numPriorityCalls = 0;

    public SpyingRpcScheduler(RpcScheduler delegate) {
      super(delegate);
    }

    @Override
    public boolean dispatch(CallRunner task) {
      int priority = task.getRpcCall().getPriority();

      if (priority > HConstants.QOS_THRESHOLD) {
        numPriorityCalls++;
      }
      return super.dispatch(task);
    }
  }

  @Test
  public void testScanByRegionEncodedNameExistingRegion() throws Exception {
    final TableName tableName = TableName.valueOf("testScanByRegionEncodedNameExistingRegion");
    UTIL.createTable(tableName, "cf");
    final List<HRegion> regions = UTIL.getHBaseCluster().getRegions(tableName);
    final String encodedName = regions.get(0).getRegionInfo().getEncodedName();
    final Result result =
      MetaTableAccessor.scanByRegionEncodedName(UTIL.getConnection(), encodedName);
    assertNotNull(result);
    assertTrue(result.advance());
    final String resultingRowKey = CellUtil.getCellKeyAsString(result.current());
    assertTrue(resultingRowKey.contains(encodedName));
    UTIL.deleteTable(tableName);
  }

  @Test
  public void testScanByRegionEncodedNameNonExistingRegion() throws Exception {
    final String encodedName = "nonexistingregion";
    final Result result =
      MetaTableAccessor.scanByRegionEncodedName(UTIL.getConnection(), encodedName);
    assertNull(result);
  }
}