/*
 * 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.regionserver.wal;

import static org.junit.jupiter.api.Assertions.assertEquals;
import static org.junit.jupiter.api.Assertions.assertThrows;
import static org.junit.jupiter.api.Assertions.assertTrue;

import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.IOException;
import org.apache.hadoop.hbase.io.util.Dictionary;
import org.apache.hadoop.hbase.io.util.LRUDictionary;
import org.apache.hadoop.hbase.testclassification.RegionServerTests;
import org.apache.hadoop.hbase.testclassification.SmallTests;
import org.apache.hadoop.hbase.util.Bytes;
import org.junit.jupiter.api.BeforeAll;
import org.junit.jupiter.api.Tag;
import org.junit.jupiter.api.Test;

/**
 * Test our compressor class.
 */
@Tag(RegionServerTests.TAG)
@Tag(SmallTests.TAG)
public class TestCompressor {

  @BeforeAll
  public static void setUpBeforeClass() throws Exception {
  }

  @Test
  public void testToShort() {
    short s = 1;
    assertEquals(s, Compressor.toShort((byte) 0, (byte) 1));
    s <<= 8;
    assertEquals(s, Compressor.toShort((byte) 1, (byte) 0));
  }

  @Test
  public void testNegativeToShort() {
    assertThrows(IllegalArgumentException.class,
      () -> Compressor.toShort((byte) 0xff, (byte) 0xff));
  }

  @Test
  public void testCompressingWithNullDictionaries() throws IOException {
    ByteArrayOutputStream baos = new ByteArrayOutputStream();
    DataOutputStream dos = new DataOutputStream(baos);
    byte[] blahBytes = Bytes.toBytes("blah");
    Compressor.writeCompressed(blahBytes, 0, blahBytes.length, dos, null);
    dos.close();
    byte[] dosbytes = baos.toByteArray();
    DataInputStream dis = new DataInputStream(new ByteArrayInputStream(dosbytes));
    byte[] product = Compressor.readCompressed(dis, null);
    assertTrue(Bytes.equals(blahBytes, product));
  }

  @Test
  public void testCompressingWithClearDictionaries() throws IOException {
    ByteArrayOutputStream baos = new ByteArrayOutputStream();
    DataOutputStream dos = new DataOutputStream(baos);
    Dictionary dictionary = new LRUDictionary();
    dictionary.init(Short.MAX_VALUE);
    byte[] blahBytes = Bytes.toBytes("blah");
    Compressor.writeCompressed(blahBytes, 0, blahBytes.length, dos, dictionary);
    dos.close();
    byte[] dosbytes = baos.toByteArray();
    DataInputStream dis = new DataInputStream(new ByteArrayInputStream(dosbytes));
    dictionary = new LRUDictionary();
    dictionary.init(Short.MAX_VALUE);
    byte[] product = Compressor.readCompressed(dis, dictionary);
    assertTrue(Bytes.equals(blahBytes, product));
  }
}
