// Copyright (c) Six Labors and contributors.
// Licensed under the Apache License, Version 2.0.

using System;
using System.Collections.Generic;
using System.Text;
using SixLabors.ImageSharp.PixelFormats;
using SixLabors.ImageSharp.PixelFormats.PixelBlenders;
using SixLabors.ImageSharp.Tests.TestUtilities;
using Xunit;

namespace SixLabors.ImageSharp.Tests.PixelFormats
{
    public class PixelBlenderTests
    {
        public static TheoryData<object, Type, PixelColorBlendingMode> BlenderMappings = new TheoryData<object, Type, PixelColorBlendingMode>()
        {
            { new TestPixel<Rgba32>(), typeof(DefaultPixelBlenders<Rgba32>.NormalSrcOver), PixelColorBlendingMode.Normal },
            { new TestPixel<Rgba32>(), typeof(DefaultPixelBlenders<Rgba32>.ScreenSrcOver), PixelColorBlendingMode.Screen },
            { new TestPixel<Rgba32>(), typeof(DefaultPixelBlenders<Rgba32>.HardLightSrcOver), PixelColorBlendingMode.HardLight },
            { new TestPixel<Rgba32>(), typeof(DefaultPixelBlenders<Rgba32>.OverlaySrcOver), PixelColorBlendingMode.Overlay },
            { new TestPixel<Rgba32>(), typeof(DefaultPixelBlenders<Rgba32>.DarkenSrcOver), PixelColorBlendingMode.Darken },
            { new TestPixel<Rgba32>(), typeof(DefaultPixelBlenders<Rgba32>.LightenSrcOver), PixelColorBlendingMode.Lighten },
            { new TestPixel<Rgba32>(), typeof(DefaultPixelBlenders<Rgba32>.AddSrcOver), PixelColorBlendingMode.Add },
            { new TestPixel<Rgba32>(), typeof(DefaultPixelBlenders<Rgba32>.SubtractSrcOver), PixelColorBlendingMode.Subtract },
            { new TestPixel<Rgba32>(), typeof(DefaultPixelBlenders<Rgba32>.MultiplySrcOver), PixelColorBlendingMode.Multiply },            

            { new TestPixel<RgbaVector>(), typeof(DefaultPixelBlenders<RgbaVector>.NormalSrcOver), PixelColorBlendingMode.Normal },
            { new TestPixel<RgbaVector>(), typeof(DefaultPixelBlenders<RgbaVector>.ScreenSrcOver), PixelColorBlendingMode.Screen },
            { new TestPixel<RgbaVector>(), typeof(DefaultPixelBlenders<RgbaVector>.HardLightSrcOver), PixelColorBlendingMode.HardLight },
            { new TestPixel<RgbaVector>(), typeof(DefaultPixelBlenders<RgbaVector>.OverlaySrcOver), PixelColorBlendingMode.Overlay },
            { new TestPixel<RgbaVector>(), typeof(DefaultPixelBlenders<RgbaVector>.DarkenSrcOver), PixelColorBlendingMode.Darken },
            { new TestPixel<RgbaVector>(), typeof(DefaultPixelBlenders<RgbaVector>.LightenSrcOver), PixelColorBlendingMode.Lighten },
            { new TestPixel<RgbaVector>(), typeof(DefaultPixelBlenders<RgbaVector>.AddSrcOver), PixelColorBlendingMode.Add },
            { new TestPixel<RgbaVector>(), typeof(DefaultPixelBlenders<RgbaVector>.SubtractSrcOver), PixelColorBlendingMode.Subtract },
            { new TestPixel<RgbaVector>(), typeof(DefaultPixelBlenders<RgbaVector>.MultiplySrcOver), PixelColorBlendingMode.Multiply },
        };

        [Theory]
        [MemberData(nameof(BlenderMappings))]
        public void ReturnsCorrectBlender<TPixel>(TestPixel<TPixel> pixel, Type type, PixelColorBlendingMode mode)
            where TPixel : struct, IPixel<TPixel>
        {
            PixelBlender<TPixel> blender = PixelOperations<TPixel>.Instance.GetPixelBlender(mode, PixelAlphaCompositionMode.SrcOver);
            Assert.IsType(type, blender);
        }
    }
}