package test;

import org.openjdk.jmh.annotations.Benchmark;
import org.openjdk.jmh.annotations.BenchmarkMode;
import org.openjdk.jmh.annotations.Mode;
import org.openjdk.jmh.annotations.OutputTimeUnit;
import org.openjdk.jmh.annotations.Scope;
import org.openjdk.jmh.annotations.State;
import org.openjdk.jmh.infra.Blackhole;

import java.util.Random;
import java.util.concurrent.TimeUnit;

import static io.vavr.API.$;
import static io.vavr.API.Case;
import static io.vavr.API.Match;
import static test.MyBenchmark.TestEnum.A;
import static test.MyBenchmark.TestEnum.B;
import static test.MyBenchmark.TestEnum.C;
import static test.MyBenchmark.TestEnum.values;


@BenchmarkMode(Mode.AverageTime)
@OutputTimeUnit(TimeUnit.MICROSECONDS)
public class MyBenchmark {

    public enum TestEnum {A, B, C}

    @State(Scope.Thread)
    public static class MyState {
        public Random r = new Random();
    }

    @Benchmark
    public void ifMethod(Blackhole bh, MyState state) {
        TestEnum sample = TestEnum.values()[state.r.nextInt(values().length)];
        TestEnum result;
        if (sample == A) {
            result = B;
        } else if (sample == B) {
            result = C;
        } else if (sample == C) {
            result = A;
        } else {
            result = A;
        }
        bh.consume(result);
    }

    @Benchmark
    public void switchMethod(Blackhole bh, MyState state) {
        TestEnum sample = TestEnum.values()[state.r.nextInt(values().length)];
        TestEnum result;
        switch (sample) {
            case A:
                result = B;
            case B:
                result = C;
            case C:
                result = A;
            default:
                result = A;
        }
        bh.consume(result);
    }

    @Benchmark
    public void vavrMethod(Blackhole bh, MyState state) {
        TestEnum sample = TestEnum.values()[state.r.nextInt(values().length)];
        bh.consume(Match(sample).of(
                Case($(A), B),
                Case($(B), C),
                Case($(C), A),
                Case($(), A)
        ));
    }

    public static void main(String[] args) throws Exception {
        org.openjdk.jmh.Main.main(args);
    }
}