/**
 * 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.io.hfile;

import static org.junit.Assert.assertEquals;

import java.io.IOException;
import java.util.ArrayList;
import java.util.Collection;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Set;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.hbase.Cell;
import org.apache.hadoop.hbase.HBaseClassTestRule;
import org.apache.hadoop.hbase.HBaseTestingUtility;
import org.apache.hadoop.hbase.HColumnDescriptor;
import org.apache.hadoop.hbase.HRegionInfo;
import org.apache.hadoop.hbase.HTableDescriptor;
import org.apache.hadoop.hbase.TableName;
import org.apache.hadoop.hbase.client.Put;
import org.apache.hadoop.hbase.client.Scan;
import org.apache.hadoop.hbase.regionserver.BloomType;
import org.apache.hadoop.hbase.regionserver.HRegion;
import org.apache.hadoop.hbase.regionserver.InternalScanner;
import org.apache.hadoop.hbase.testclassification.IOTests;
import org.apache.hadoop.hbase.testclassification.SmallTests;
import org.apache.hadoop.hbase.util.Bytes;
import org.junit.AfterClass;
import org.junit.ClassRule;
import org.junit.Test;
import org.junit.experimental.categories.Category;
import org.junit.runner.RunWith;
import org.junit.runners.Parameterized;
import org.junit.runners.Parameterized.Parameters;

/**
 * Test the optimization that does not scan files where all key ranges are excluded.
 */
@RunWith(Parameterized.class)
@Category({IOTests.class, SmallTests.class})
public class TestScannerSelectionUsingKeyRange {

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

  private static final HBaseTestingUtility TEST_UTIL = HBaseTestingUtility.createLocalHTU();
  private static TableName TABLE = TableName.valueOf("myTable");
  private static String FAMILY = "myCF";
  private static byte[] FAMILY_BYTES = Bytes.toBytes(FAMILY);
  private static final int NUM_ROWS = 8;
  private static final int NUM_COLS_PER_ROW = 5;
  private static final int NUM_FILES = 2;
  private static final Map<Object, Integer> TYPE_COUNT = new HashMap<>(3);
  static {
    TYPE_COUNT.put(BloomType.ROWCOL, 0);
    TYPE_COUNT.put(BloomType.ROW, 0);
    TYPE_COUNT.put(BloomType.NONE, 0);
  }

  private BloomType bloomType;
  private int expectedCount;

  @Parameters
  public static Collection<Object[]> parameters() {
    List<Object[]> params = new ArrayList<>();
    for (Object type : TYPE_COUNT.keySet()) {
      params.add(new Object[] { type, TYPE_COUNT.get(type) });
    }
    return params;
  }

  public TestScannerSelectionUsingKeyRange(Object type, Object count) {
    bloomType = (BloomType)type;
    expectedCount = (Integer) count;
  }

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

  @Test
  public void testScannerSelection() throws IOException {
    Configuration conf = TEST_UTIL.getConfiguration();
    conf.setInt("hbase.hstore.compactionThreshold", 10000);
    HColumnDescriptor hcd = new HColumnDescriptor(FAMILY_BYTES).setBlockCacheEnabled(true)
        .setBloomFilterType(bloomType);
    HTableDescriptor htd = new HTableDescriptor(TABLE);
    htd.addFamily(hcd);
    HRegionInfo info = new HRegionInfo(TABLE);
    HRegion region = HBaseTestingUtility.createRegionAndWAL(info, TEST_UTIL.getDataTestDir(), conf,
        htd);

    for (int iFile = 0; iFile < NUM_FILES; ++iFile) {
      for (int iRow = 0; iRow < NUM_ROWS; ++iRow) {
        Put put = new Put(Bytes.toBytes("row" + iRow));
        for (int iCol = 0; iCol < NUM_COLS_PER_ROW; ++iCol) {
          put.addColumn(FAMILY_BYTES, Bytes.toBytes("col" + iCol),
                  Bytes.toBytes("value" + iFile + "_" + iRow + "_" + iCol));
        }
        region.put(put);
      }
      region.flush(true);
    }

    Scan scan = new Scan(Bytes.toBytes("aaa"), Bytes.toBytes("aaz"));
    BlockCache cache = BlockCacheFactory.createBlockCache(conf);
    InternalScanner scanner = region.getScanner(scan);
    List<Cell> results = new ArrayList<>();
    while (scanner.next(results)) {
    }
    scanner.close();
    assertEquals(0, results.size());
    if (cache instanceof LruBlockCache) {
      Set<String> accessedFiles = ((LruBlockCache)cache).getCachedFileNamesForTest();
      assertEquals(expectedCount, accessedFiles.size());
    }
    HBaseTestingUtility.closeRegionAndWAL(region);
  }
}
