/*
 * 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.arrow.memory.util;

import java.util.concurrent.TimeUnit;

import org.apache.arrow.memory.BufferAllocator;
import org.apache.arrow.memory.RootAllocator;
import org.openjdk.jmh.annotations.Benchmark;
import org.openjdk.jmh.annotations.BenchmarkMode;
import org.openjdk.jmh.annotations.Level;
import org.openjdk.jmh.annotations.Mode;
import org.openjdk.jmh.annotations.OutputTimeUnit;
import org.openjdk.jmh.annotations.Scope;
import org.openjdk.jmh.annotations.Setup;
import org.openjdk.jmh.annotations.State;
import org.openjdk.jmh.annotations.TearDown;
import org.openjdk.jmh.runner.Runner;
import org.openjdk.jmh.runner.RunnerException;
import org.openjdk.jmh.runner.options.Options;
import org.openjdk.jmh.runner.options.OptionsBuilder;

import io.netty.buffer.ArrowBuf;

/**
 * Benchmarks for {@link ByteFunctionHelpers}.
 */
public class ByteFunctionHelpersBenchmarks {

  private static final int ALLOCATOR_CAPACITY = 1024 * 1024;

  /**
   * State object for the {@link ByteFunctionHelpersBenchmarks#arrowBufEquals(ArrowEqualState)} benchmark.
   */
  @State(Scope.Benchmark)
  public static class ArrowEqualState {

    private static final int BUFFER_CAPACITY = 7;

    private BufferAllocator allocator;

    private ArrowBuf buffer1;

    private ArrowBuf buffer2;

    @Setup(Level.Trial)
    public void prepare() {
      allocator = new RootAllocator(ALLOCATOR_CAPACITY);
      buffer1 = allocator.buffer(BUFFER_CAPACITY);
      buffer2 = allocator.buffer(BUFFER_CAPACITY);

      for (int i = 0; i < BUFFER_CAPACITY; i++) {
        buffer1.setByte(i, i);
        buffer2.setByte(i, i);
      }
    }

    @TearDown(Level.Trial)
    public void tearDown() {
      buffer1.close();
      buffer2.close();
      allocator.close();
    }
  }

  @Benchmark
  @BenchmarkMode(Mode.AverageTime)
  @OutputTimeUnit(TimeUnit.NANOSECONDS)
  public void arrowBufEquals(ArrowEqualState state) {
    ByteFunctionHelpers.equal(state.buffer1, 0, ArrowEqualState.BUFFER_CAPACITY - 1,
            state.buffer2, 0, ArrowEqualState.BUFFER_CAPACITY - 1);
  }

  /**
   * State object for the {@link ByteFunctionHelpersBenchmarks#arrowBufArrayEquals(ArrowArrayEqualState)} benchmark.
   */
  @State(Scope.Benchmark)
  public static class ArrowArrayEqualState {

    private static final int BUFFER_CAPACITY = 1024;

    private BufferAllocator allocator;

    private ArrowBuf buffer1;

    private byte[] buffer2;

    @Setup(Level.Trial)
    public void prepare() {
      allocator = new RootAllocator(ALLOCATOR_CAPACITY);
      buffer1 = allocator.buffer(BUFFER_CAPACITY);
      buffer2 = new byte[BUFFER_CAPACITY];

      for (int i = 0; i < BUFFER_CAPACITY; i++) {
        buffer1.setByte(i, i);
        buffer2[i] = (byte) i;
      }
    }

    @TearDown(Level.Trial)
    public void tearDown() {
      buffer1.close();
      allocator.close();
    }
  }

  @Benchmark
  @BenchmarkMode(Mode.AverageTime)
  @OutputTimeUnit(TimeUnit.NANOSECONDS)
  public int arrowBufArrayEquals(ArrowArrayEqualState state) {
    return ByteFunctionHelpers.compare(
            state.buffer1, 0, ArrowArrayEqualState.BUFFER_CAPACITY,
            state.buffer2, 0, ArrowArrayEqualState.BUFFER_CAPACITY);
  }

  public static void main(String[] args) throws RunnerException {
    Options opt = new OptionsBuilder()
        .include(ByteFunctionHelpersBenchmarks.class.getSimpleName())
        .forks(1)
        .build();

    new Runner(opt).run();
  }
}
