/*
 * 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.client;

import static org.junit.Assert.assertEquals;
import static org.junit.Assert.assertTrue;

import java.io.IOException;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import java.util.Optional;
import java.util.concurrent.CountDownLatch;
import java.util.concurrent.atomic.AtomicBoolean;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.hbase.Cell;
import org.apache.hadoop.hbase.CellComparatorImpl;
import org.apache.hadoop.hbase.HBaseClassTestRule;
import org.apache.hadoop.hbase.HBaseTestingUtility;
import org.apache.hadoop.hbase.HConstants;
import org.apache.hadoop.hbase.TableName;
import org.apache.hadoop.hbase.coprocessor.CoprocessorHost;
import org.apache.hadoop.hbase.coprocessor.MultiRowMutationEndpoint;
import org.apache.hadoop.hbase.coprocessor.ObserverContext;
import org.apache.hadoop.hbase.coprocessor.RegionCoprocessor;
import org.apache.hadoop.hbase.coprocessor.RegionCoprocessorEnvironment;
import org.apache.hadoop.hbase.coprocessor.RegionObserver;
import org.apache.hadoop.hbase.io.hfile.BlockCache;
import org.apache.hadoop.hbase.io.hfile.BlockCacheKey;
import org.apache.hadoop.hbase.io.hfile.CacheConfig;
import org.apache.hadoop.hbase.io.hfile.CachedBlock;
import org.apache.hadoop.hbase.io.hfile.CombinedBlockCache;
import org.apache.hadoop.hbase.io.hfile.bucket.BucketCache;
import org.apache.hadoop.hbase.regionserver.DelegatingInternalScanner;
import org.apache.hadoop.hbase.regionserver.HRegion;
import org.apache.hadoop.hbase.regionserver.HStore;
import org.apache.hadoop.hbase.regionserver.InternalScanner;
import org.apache.hadoop.hbase.regionserver.ScanType;
import org.apache.hadoop.hbase.regionserver.ScannerContext;
import org.apache.hadoop.hbase.regionserver.Store;
import org.apache.hadoop.hbase.regionserver.compactions.CompactionLifeCycleTracker;
import org.apache.hadoop.hbase.regionserver.compactions.CompactionRequest;
import org.apache.hadoop.hbase.testclassification.ClientTests;
import org.apache.hadoop.hbase.testclassification.LargeTests;
import org.apache.hadoop.hbase.util.Bytes;
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.apache.hbase.thirdparty.com.google.common.collect.Iterables;

@Category({ LargeTests.class, ClientTests.class })
public class TestAvoidCellReferencesIntoShippedBlocks {

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

  protected final static HBaseTestingUtility TEST_UTIL = new HBaseTestingUtility();
  static byte[][] ROWS = new byte[2][];
  private static byte[] ROW = Bytes.toBytes("testRow");
  private static byte[] ROW1 = Bytes.toBytes("testRow1");
  private static byte[] ROW2 = Bytes.toBytes("testRow2");
  private static byte[] ROW3 = Bytes.toBytes("testRow3");
  private static byte[] ROW4 = Bytes.toBytes("testRow4");
  private static byte[] ROW5 = Bytes.toBytes("testRow5");
  private static byte[] FAMILY = Bytes.toBytes("testFamily");
  private static byte[][] FAMILIES_1 = new byte[1][0];
  private static byte[] QUALIFIER = Bytes.toBytes("testQualifier");
  private static byte[] QUALIFIER1 = Bytes.toBytes("testQualifier1");
  private static byte[] data = new byte[1000];
  protected static int SLAVES = 1;
  private CountDownLatch latch = new CountDownLatch(1);
  private static CountDownLatch compactReadLatch = new CountDownLatch(1);
  private static AtomicBoolean doScan = new AtomicBoolean(false);

  @Rule
  public TestName name = new TestName();

  /**
   * @throws java.lang.Exception
   */
  @BeforeClass
  public static void setUpBeforeClass() throws Exception {
    ROWS[0] = ROW;
    ROWS[1] = ROW1;
    Configuration conf = TEST_UTIL.getConfiguration();
    conf.setStrings(CoprocessorHost.REGION_COPROCESSOR_CONF_KEY,
      MultiRowMutationEndpoint.class.getName());
    conf.setInt("hbase.regionserver.handler.count", 20);
    conf.setInt("hbase.bucketcache.size", 400);
    conf.setStrings(HConstants.BUCKET_CACHE_IOENGINE_KEY, "offheap");
    conf.setInt("hbase.hstore.compactionThreshold", 7);
    conf.setFloat("hfile.block.cache.size", 0.2f);
    conf.setFloat("hbase.regionserver.global.memstore.size", 0.1f);
    conf.setInt(HConstants.HBASE_CLIENT_RETRIES_NUMBER, 0);// do not retry
    conf.setInt(HConstants.HBASE_CLIENT_SCANNER_TIMEOUT_PERIOD, 500000);
    FAMILIES_1[0] = FAMILY;
    TEST_UTIL.startMiniCluster(SLAVES);
    compactReadLatch = new CountDownLatch(1);
  }

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

  @Test
  public void testHBase16372InCompactionWritePath() throws Exception {
    final TableName tableName = TableName.valueOf(name.getMethodName());
    // Create a table with block size as 1024
    final Table table = TEST_UTIL.createTable(tableName, FAMILIES_1, 1, 1024,
      CompactorRegionObserver.class.getName());
    try {
      // get the block cache and region
      RegionLocator locator = TEST_UTIL.getConnection().getRegionLocator(tableName);
      String regionName = locator.getAllRegionLocations().get(0).getRegion().getEncodedName();
      HRegion region =
        (HRegion) TEST_UTIL.getRSForFirstRegionInTable(tableName).getRegion(regionName);
      HStore store = region.getStores().iterator().next();
      CacheConfig cacheConf = store.getCacheConfig();
      cacheConf.setCacheDataOnWrite(true);
      cacheConf.setEvictOnClose(true);
      final BlockCache cache = cacheConf.getBlockCache().get();
      // insert data. 5 Rows are added
      Put put = new Put(ROW);
      put.addColumn(FAMILY, QUALIFIER, data);
      table.put(put);
      put = new Put(ROW);
      put.addColumn(FAMILY, QUALIFIER1, data);
      table.put(put);
      put = new Put(ROW1);
      put.addColumn(FAMILY, QUALIFIER, data);
      table.put(put);
      // data was in memstore so don't expect any changes
      region.flush(true);
      put = new Put(ROW1);
      put.addColumn(FAMILY, QUALIFIER1, data);
      table.put(put);
      put = new Put(ROW2);
      put.addColumn(FAMILY, QUALIFIER, data);
      table.put(put);
      put = new Put(ROW2);
      put.addColumn(FAMILY, QUALIFIER1, data);
      table.put(put);
      // data was in memstore so don't expect any changes
      region.flush(true);
      put = new Put(ROW3);
      put.addColumn(FAMILY, QUALIFIER, data);
      table.put(put);
      put = new Put(ROW3);
      put.addColumn(FAMILY, QUALIFIER1, data);
      table.put(put);
      put = new Put(ROW4);
      put.addColumn(FAMILY, QUALIFIER, data);
      table.put(put);
      // data was in memstore so don't expect any changes
      region.flush(true);
      put = new Put(ROW4);
      put.addColumn(FAMILY, QUALIFIER1, data);
      table.put(put);
      put = new Put(ROW5);
      put.addColumn(FAMILY, QUALIFIER, data);
      table.put(put);
      put = new Put(ROW5);
      put.addColumn(FAMILY, QUALIFIER1, data);
      table.put(put);
      // data was in memstore so don't expect any changes
      region.flush(true);
      // Load cache
      Scan s = new Scan();
      s.setMaxResultSize(1000);
      int count;
      try (ResultScanner scanner = table.getScanner(s)) {
        count = Iterables.size(scanner);
      }
      assertEquals("Count all the rows ", 6, count);
      // all the cache is loaded
      // trigger a major compaction
      ScannerThread scannerThread = new ScannerThread(table, cache);
      scannerThread.start();
      region.compact(true);
      s = new Scan();
      s.setMaxResultSize(1000);
      try (ResultScanner scanner = table.getScanner(s)) {
        count = Iterables.size(scanner);
      }
      assertEquals("Count all the rows ", 6, count);
    } finally {
      table.close();
    }
  }

  private static class ScannerThread extends Thread {
    private final Table table;
    private final BlockCache cache;

    public ScannerThread(Table table, BlockCache cache) {
      this.table = table;
      this.cache = cache;
    }

    @Override
    public void run() {
      Scan s = new Scan().withStartRow(ROW4).withStopRow(ROW5).setCaching(1);
      try {
        while (!doScan.get()) {
          try {
            // Sleep till you start scan
            Thread.sleep(1);
          } catch (InterruptedException e) {
          }
        }
        List<BlockCacheKey> cacheList = new ArrayList<>();
        Iterator<CachedBlock> iterator = cache.iterator();
        // evict all the blocks
        while (iterator.hasNext()) {
          CachedBlock next = iterator.next();
          BlockCacheKey cacheKey = new BlockCacheKey(next.getFilename(), next.getOffset());
          cacheList.add(cacheKey);
          // evict what ever is available
          cache.evictBlock(cacheKey);
        }
        try (ResultScanner scanner = table.getScanner(s)) {
          while (scanner.next() != null) {
          }
        }
        compactReadLatch.countDown();
      } catch (IOException e) {
      }
    }
  }

  public static class CompactorRegionObserver implements RegionCoprocessor, RegionObserver {

    @Override
    public Optional<RegionObserver> getRegionObserver() {
      return Optional.of(this);
    }

    @Override
    public InternalScanner preCompact(ObserverContext<RegionCoprocessorEnvironment> c, Store store,
      InternalScanner scanner, ScanType scanType, CompactionLifeCycleTracker tracker,
      CompactionRequest request) throws IOException {
      return new CompactorInternalScanner(scanner);
    }
  }

  private static final class CompactorInternalScanner extends DelegatingInternalScanner {

    public CompactorInternalScanner(InternalScanner scanner) {
      super(scanner);
    }

    @Override
    public boolean next(List<Cell> result, ScannerContext scannerContext) throws IOException {
      boolean next = scanner.next(result, scannerContext);
      for (Cell cell : result) {
        if (CellComparatorImpl.COMPARATOR.compareRows(cell, ROW2, 0, ROW2.length) == 0) {
          try {
            // hold the compaction
            // set doscan to true
            doScan.compareAndSet(false, true);
            compactReadLatch.await();
          } catch (InterruptedException e) {
          }
        }
      }
      return next;
    }
  }

  @Test
  public void testHBASE16372InReadPath() throws Exception {
    final TableName tableName = TableName.valueOf(name.getMethodName());
    // Create a table with block size as 1024
    final Table table = TEST_UTIL.createTable(tableName, FAMILIES_1, 1, 1024, null);
    try {
      // get the block cache and region
      RegionLocator locator = TEST_UTIL.getConnection().getRegionLocator(tableName);
      String regionName = locator.getAllRegionLocations().get(0).getRegion().getEncodedName();
      HRegion region =
        (HRegion) TEST_UTIL.getRSForFirstRegionInTable(tableName).getRegion(regionName);
      HStore store = region.getStores().iterator().next();
      CacheConfig cacheConf = store.getCacheConfig();
      cacheConf.setCacheDataOnWrite(true);
      cacheConf.setEvictOnClose(true);
      final BlockCache cache = cacheConf.getBlockCache().get();
      // insert data. 5 Rows are added
      Put put = new Put(ROW);
      put.addColumn(FAMILY, QUALIFIER, data);
      table.put(put);
      put = new Put(ROW);
      put.addColumn(FAMILY, QUALIFIER1, data);
      table.put(put);
      put = new Put(ROW1);
      put.addColumn(FAMILY, QUALIFIER, data);
      table.put(put);
      put = new Put(ROW1);
      put.addColumn(FAMILY, QUALIFIER1, data);
      table.put(put);
      put = new Put(ROW2);
      put.addColumn(FAMILY, QUALIFIER, data);
      table.put(put);
      put = new Put(ROW2);
      put.addColumn(FAMILY, QUALIFIER1, data);
      table.put(put);
      put = new Put(ROW3);
      put.addColumn(FAMILY, QUALIFIER, data);
      table.put(put);
      put = new Put(ROW3);
      put.addColumn(FAMILY, QUALIFIER1, data);
      table.put(put);
      put = new Put(ROW4);
      put.addColumn(FAMILY, QUALIFIER, data);
      table.put(put);
      put = new Put(ROW4);
      put.addColumn(FAMILY, QUALIFIER1, data);
      table.put(put);
      put = new Put(ROW5);
      put.addColumn(FAMILY, QUALIFIER, data);
      table.put(put);
      put = new Put(ROW5);
      put.addColumn(FAMILY, QUALIFIER1, data);
      table.put(put);
      // data was in memstore so don't expect any changes
      region.flush(true);
      // Load cache
      Scan s = new Scan();
      s.setMaxResultSize(1000);
      int count;
      try (ResultScanner scanner = table.getScanner(s)) {
        count = Iterables.size(scanner);
      }
      assertEquals("Count all the rows ", 6, count);

      // Scan from cache
      s = new Scan();
      // Start a scan from row3
      s.setCaching(1);
      s.withStartRow(ROW1);
      // set partial as true so that the scan can send partial columns also
      s.setAllowPartialResults(true);
      s.setMaxResultSize(1000);
      try (ResultScanner scanner = table.getScanner(s)) {
        Thread evictorThread = new Thread() {
          @Override
          public void run() {
            List<BlockCacheKey> cacheList = new ArrayList<>();
            Iterator<CachedBlock> iterator = cache.iterator();
            // evict all the blocks
            while (iterator.hasNext()) {
              CachedBlock next = iterator.next();
              BlockCacheKey cacheKey = new BlockCacheKey(next.getFilename(), next.getOffset());
              cacheList.add(cacheKey);
              /**
               * There is only one Block referenced by rpc,here we evict blocks which have no rpc
               * referenced.
               */
              evictBlock(cache, cacheKey);
            }
            try {
              Thread.sleep(1);
            } catch (InterruptedException e1) {
            }
            iterator = cache.iterator();
            int refBlockCount = 0;
            while (iterator.hasNext()) {
              iterator.next();
              refBlockCount++;
            }
            assertEquals("One block should be there ", 1, refBlockCount);
            // Rescan to prepopulate the data
            // cache this row.
            Scan s1 = new Scan();
            // This scan will start from ROW1 and it will populate the cache with a
            // row that is lower than ROW3.
            s1.withStartRow(ROW3);
            s1.withStopRow(ROW5);
            s1.setCaching(1);
            ResultScanner scanner;
            try {
              scanner = table.getScanner(s1);
              int count = Iterables.size(scanner);
              assertEquals("Count the rows", 2, count);
              int newBlockRefCount = 0;
              List<BlockCacheKey> newCacheList = new ArrayList<>();
              while (true) {
                newBlockRefCount = 0;
                newCacheList.clear();
                iterator = cache.iterator();
                while (iterator.hasNext()) {
                  CachedBlock next = iterator.next();
                  BlockCacheKey cacheKey = new BlockCacheKey(next.getFilename(), next.getOffset());
                  newCacheList.add(cacheKey);
                }
                for (BlockCacheKey key : cacheList) {
                  if (newCacheList.contains(key)) {
                    newBlockRefCount++;
                  }
                }
                if (newBlockRefCount == 6) {
                  break;
                }
              }
              latch.countDown();
            } catch (IOException e) {
            }
          }
        };
        count = 0;
        while (scanner.next() != null) {
          count++;
          if (count == 2) {
            evictorThread.start();
            latch.await();
          }
        }
      }
      assertEquals("Count should give all rows ", 10, count);
    } finally {
      table.close();
    }
  }

  /**
   * For {@link BucketCache},we only evict Block if there is no rpc referenced.
   */
  private void evictBlock(BlockCache blockCache, BlockCacheKey blockCacheKey) {
    assertTrue(blockCache instanceof CombinedBlockCache);
    BlockCache[] blockCaches = blockCache.getBlockCaches();
    for (BlockCache currentBlockCache : blockCaches) {
      if (currentBlockCache instanceof BucketCache) {
        ((BucketCache) currentBlockCache).evictBlockIfNoRpcReferenced(blockCacheKey);
      } else {
        currentBlockCache.evictBlock(blockCacheKey);
      }
    }

  }
}