package jmhmath;

import org.openjdk.jmh.annotations.*;
import org.openjdk.jmh.infra.Blackhole;
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 java.io.IOException;
import java.math.BigDecimal;
import java.math.MathContext;
import java.util.Locale;
import java.util.Random;
import java.util.concurrent.TimeUnit;

@Fork(value = 0, warmups = 0)
@OutputTimeUnit(TimeUnit.NANOSECONDS)
@BenchmarkMode(Mode.AverageTime)
@State(Scope.Benchmark)
public class BigDecimalBenchmark {

    private Blackhole blackhole;
    private Random random;

    @Setup(Level.Trial)
    public void init(Blackhole blackhole){
        this.blackhole = blackhole;
        this.random = new Random();
    }


    @Benchmark
    public void testDoubleMath(){
        double d = (random.nextDouble()+random.nextDouble())/20;
        blackhole.consume(d);
    }


    @Benchmark
    public void testBigDecimalMath(){
        BigDecimal d = (BigDecimal.valueOf(random.nextDouble()).add(BigDecimal.valueOf(random.nextDouble()))).divide(BigDecimal.valueOf(20));
        blackhole.consume(d);
    }

    @Benchmark
    public void testBigDecimalMathWithEval(){
        double d = (BigDecimal.valueOf(random.nextDouble()).add(BigDecimal.valueOf(random.nextDouble()))).divide(BigDecimal.valueOf(20)).doubleValue();
        blackhole.consume(d);
    }

    @Benchmark
    public void testQuadruple(){
        double d = new Quadruple(random.nextDouble()).add(random.nextDouble()).divide(20).doubleValue();
        blackhole.consume(d);
    }


    private void run(String... args) throws IOException, RunnerException {
        Locale.setDefault(Locale.US);
        final Options opt = new OptionsBuilder()
                .include(BigDecimalBenchmark.class.getSimpleName())
                .forks(1)
                .build();
        new Runner(opt).run();
    }

    public static void main(String... args) throws IOException, RunnerException {
        new BigDecimalBenchmark().run(args);
    }
}