// Copyright (c) Six Labors.
// Licensed under the Six Labors Split License.

using System.Buffers;
using BenchmarkDotNet.Attributes;

using SixLabors.ImageSharp.Memory;
using SixLabors.ImageSharp.PixelFormats;

// ReSharper disable InconsistentNaming
namespace SixLabors.ImageSharp.Benchmarks.Bulk;

public abstract class FromRgba32Bytes<TPixel>
    where TPixel : unmanaged, IPixel<TPixel>
{
    private IMemoryOwner<TPixel> destination;

    private IMemoryOwner<byte> source;

    private Configuration configuration;

    [Params(
        128,
        1024,
        2048)]
    public int Count { get; set; }

    [GlobalSetup]
    public void Setup()
    {
        this.configuration = Configuration.Default;
        this.destination = this.configuration.MemoryAllocator.Allocate<TPixel>(this.Count);
        this.source = this.configuration.MemoryAllocator.Allocate<byte>(this.Count * 4);
    }

    [GlobalCleanup]
    public void Cleanup()
    {
        this.destination.Dispose();
        this.source.Dispose();
    }

    // [Benchmark]
    public void Naive()
    {
        Span<byte> s = this.source.GetSpan();
        Span<TPixel> d = this.destination.GetSpan();

        for (int i = 0; i < this.Count; i++)
        {
            int i4 = i * 4;
            d[i] = TPixel.FromRgba32(new Rgba32(s[i4], s[i4 + 1], s[i4 + 2], s[i4 + 3]));
        }
    }

    [Benchmark(Baseline = true)]
    public void CommonBulk()
        => new PixelOperations<TPixel>().FromRgba32Bytes(this.configuration, this.source.GetSpan(), this.destination.GetSpan(), this.Count);

    [Benchmark]
    public void OptimizedBulk()
        => PixelOperations<TPixel>.Instance.FromRgba32Bytes(this.configuration, this.source.GetSpan(), this.destination.GetSpan(), this.Count);
}

public class FromRgba32Bytes_ToRgba32 : FromRgba32Bytes<Rgba32>;

public class FromRgba32Bytes_ToBgra32 : FromRgba32Bytes<Bgra32>
{
    // RESULTS:
    //         Method | Count |       Mean |     Error |    StdDev | Scaled |
    // -------------- |------ |-----------:|----------:|----------:|-------:|
    //     CommonBulk |   128 |   207.1 ns |  3.723 ns |  3.300 ns |   1.00 |
    //  OptimizedBulk |   128 |   166.5 ns |  1.204 ns |  1.005 ns |   0.80 |
    //                |       |            |           |           |        |
    //     CommonBulk |  1024 | 1,333.9 ns | 12.426 ns | 11.624 ns |   1.00 |
    //  OptimizedBulk |  1024 |   974.1 ns | 18.803 ns | 16.669 ns |   0.73 |
    //                |       |            |           |           |        |
    //     CommonBulk |  2048 | 2,625.4 ns | 30.143 ns | 26.721 ns |   1.00 |
    //  OptimizedBulk |  2048 | 1,843.0 ns | 20.505 ns | 18.177 ns |   0.70 |
}