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package org.openjdk.bench.jdk.incubator.foreign;

import jdk.incubator.foreign.ResourceScope;
import org.openjdk.jmh.annotations.Benchmark;
import org.openjdk.jmh.annotations.BenchmarkMode;
import org.openjdk.jmh.annotations.CompilerControl;
import org.openjdk.jmh.annotations.Fork;
import org.openjdk.jmh.annotations.Measurement;
import org.openjdk.jmh.annotations.Mode;
import org.openjdk.jmh.annotations.OutputTimeUnit;
import org.openjdk.jmh.annotations.Setup;
import org.openjdk.jmh.annotations.State;
import org.openjdk.jmh.annotations.TearDown;
import org.openjdk.jmh.annotations.Warmup;
import sun.misc.Unsafe;

import jdk.incubator.foreign.MemorySegment;
import java.nio.ByteBuffer;
import java.nio.IntBuffer;
import java.util.concurrent.TimeUnit;

import static jdk.incubator.foreign.ValueLayout.JAVA_INT;

@BenchmarkMode(Mode.AverageTime)
@Warmup(iterations = 5, time = 500, timeUnit = TimeUnit.MILLISECONDS)
@Measurement(iterations = 10, time = 500, timeUnit = TimeUnit.MILLISECONDS)
@State(org.openjdk.jmh.annotations.Scope.Thread)
@OutputTimeUnit(TimeUnit.MILLISECONDS)
@Fork(value = 3, jvmArgsAppend = { "--add-modules=jdk.incubator.foreign" })
public class BulkOps {

    static final Unsafe unsafe = Utils.unsafe;

    static final int ELEM_SIZE = 1_000_000;
    static final int CARRIER_SIZE = (int)JAVA_INT.byteSize();
    static final int ALLOC_SIZE = ELEM_SIZE * CARRIER_SIZE;

    final ResourceScope scope = ResourceScope.newConfinedScope();

    final long unsafe_addr = unsafe.allocateMemory(ALLOC_SIZE);
    final MemorySegment segment = MemorySegment.allocateNative(ALLOC_SIZE, ResourceScope.newConfinedScope());
    final IntBuffer buffer = IntBuffer.allocate(ELEM_SIZE);

    final int[] bytes = new int[ELEM_SIZE];
    final MemorySegment bytesSegment = MemorySegment.ofArray(bytes);
    final int UNSAFE_INT_OFFSET = unsafe.arrayBaseOffset(int[].class);

    // large(ish) segments/buffers with same content, 0, for mismatch, non-multiple-of-8 sized
    static final int SIZE_WITH_TAIL = (1024 * 1024) + 7;
    final MemorySegment mismatchSegmentLarge1 = MemorySegment.allocateNative(SIZE_WITH_TAIL, scope);
    final MemorySegment mismatchSegmentLarge2 = MemorySegment.allocateNative(SIZE_WITH_TAIL, scope);
    final ByteBuffer mismatchBufferLarge1 = ByteBuffer.allocateDirect(SIZE_WITH_TAIL);
    final ByteBuffer mismatchBufferLarge2 = ByteBuffer.allocateDirect(SIZE_WITH_TAIL);

    // mismatch at first byte
    final MemorySegment mismatchSegmentSmall1 = MemorySegment.allocateNative(7, scope);
    final MemorySegment mismatchSegmentSmall2 = MemorySegment.allocateNative(7, scope);
    final ByteBuffer mismatchBufferSmall1 = ByteBuffer.allocateDirect(7);
    final ByteBuffer mismatchBufferSmall2 = ByteBuffer.allocateDirect(7);

    @Setup
    public void setup() {
        mismatchSegmentSmall1.fill((byte) 0xFF);
        mismatchBufferSmall1.put((byte) 0xFF).clear();
        // verify expected mismatch indices
        long si = mismatchSegmentLarge1.mismatch(mismatchSegmentLarge2);
        if (si != -1)
            throw new AssertionError("Unexpected mismatch index:" + si);
        int bi = mismatchBufferLarge1.mismatch(mismatchBufferLarge2);
        if (bi != -1)
            throw new AssertionError("Unexpected mismatch index:" + bi);
        si = mismatchSegmentSmall1.mismatch(mismatchSegmentSmall2);
        if (si != 0)
            throw new AssertionError("Unexpected mismatch index:" + si);
        bi = mismatchBufferSmall1.mismatch(mismatchBufferSmall2);
        if (bi != 0)
            throw new AssertionError("Unexpected mismatch index:" + bi);

        for (int i = 0 ; i < bytes.length ; i++) {
            bytes[i] = i;
        }
    }

    @TearDown
    public void tearDown() {
        scope.close();
    }

    @Benchmark
    @OutputTimeUnit(TimeUnit.NANOSECONDS)
    public void unsafe_fill() {
        unsafe.setMemory(unsafe_addr, ALLOC_SIZE, (byte)42);
    }

    @Benchmark
    @OutputTimeUnit(TimeUnit.NANOSECONDS)
    public void segment_fill() {
        segment.fill((byte)42);
    }

    @Benchmark
    @OutputTimeUnit(TimeUnit.NANOSECONDS)
    public void unsafe_copy() {
        unsafe.copyMemory(bytes, UNSAFE_INT_OFFSET, null, unsafe_addr, ALLOC_SIZE);
    }

    @Benchmark
    @OutputTimeUnit(TimeUnit.NANOSECONDS)
    public void segment_copy() {
        segment.copyFrom(bytesSegment);
    }

    @Benchmark
    @OutputTimeUnit(TimeUnit.NANOSECONDS)
    public void segment_copy_static() {
        MemorySegment.copy(bytes, 0, segment, JAVA_INT, 0, bytes.length);
    }

    @Benchmark
    @OutputTimeUnit(TimeUnit.NANOSECONDS)
    public void segment_copy_static_small() {
        MemorySegment.copy(bytes, 0, segment, JAVA_INT, 0, 10);
    }

    @Benchmark
    @CompilerControl(CompilerControl.Mode.DONT_INLINE)
    @OutputTimeUnit(TimeUnit.NANOSECONDS)
    public void segment_copy_static_small_dontinline() {
        MemorySegment.copy(bytes, 0, segment, JAVA_INT, 0, 10);
    }

    @Benchmark
    @OutputTimeUnit(TimeUnit.NANOSECONDS)
    public void unsafe_copy_small() {
        unsafe.copyMemory(bytes, UNSAFE_INT_OFFSET, null, unsafe_addr, 10 * CARRIER_SIZE);
    }

    @Benchmark
    @OutputTimeUnit(TimeUnit.NANOSECONDS)
    public void buffer_copy_small() {
        buffer.put(0, bytes, 0, 10);
    }

    @Benchmark
    @OutputTimeUnit(TimeUnit.NANOSECONDS)
    public void buffer_copy() {
        buffer.put(0, bytes, 0, bytes.length);
    }

    @Benchmark
    @CompilerControl(CompilerControl.Mode.DONT_INLINE)
    @OutputTimeUnit(TimeUnit.NANOSECONDS)
    public void segment_copy_static_dontinline() {
        MemorySegment.copy(bytes, 0, segment, JAVA_INT, 0, bytes.length);
    }

    @Benchmark
    @OutputTimeUnit(TimeUnit.NANOSECONDS)
    public long mismatch_large_segment() {
        return mismatchSegmentLarge1.mismatch(mismatchSegmentLarge2);
    }

    @Benchmark
    @OutputTimeUnit(TimeUnit.NANOSECONDS)
    public int mismatch_large_bytebuffer() {
        return mismatchBufferLarge1.mismatch(mismatchBufferLarge2);
    }

    @Benchmark
    @OutputTimeUnit(TimeUnit.NANOSECONDS)
    public long mismatch_small_segment() {
        return mismatchSegmentSmall1.mismatch(mismatchSegmentSmall2);
    }

    @Benchmark
    @OutputTimeUnit(TimeUnit.NANOSECONDS)
    public int mismatch_small_bytebuffer() {
        return mismatchBufferSmall1.mismatch(mismatchBufferSmall2);
    }
}
