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

using System.IO;
using System.Numerics;
using SixLabors.ImageSharp.Drawing;
using SixLabors.ImageSharp.Drawing.Pens;
using SixLabors.ImageSharp.PixelFormats;
using SixLabors.ImageSharp.Tests.Drawing;
using SixLabors.Shapes;
using Xunit;

namespace SixLabors.ImageSharp.Tests.Drawing
{
    using SixLabors.ImageSharp.Processing;
    using SixLabors.ImageSharp.Processing.Overlays;

    public class LineComplexPolygonTests : FileTestBase
    {
        [Fact]
        public void ImageShouldBeOverlayedByPolygonOutline()
        {
            string path = TestEnvironment.CreateOutputDirectory("Drawing", "LineComplexPolygon");

            Polygon simplePath = new Polygon(new LinearLineSegment(
                            new Vector2(10, 10),
                            new Vector2(200, 150),
                            new Vector2(50, 300)));

            Polygon hole1 = new Polygon(new LinearLineSegment(
                            new Vector2(37, 85),
                            new Vector2(93, 85),
                            new Vector2(65, 137)));

            using (Image<Rgba32> image = new Image<Rgba32>(500, 500))
            {
                image.Mutate(x => x
                    .BackgroundColor(Rgba32.Blue)
                    .Draw(Rgba32.HotPink, 5, simplePath.Clip(hole1)));
                image.Save($"{path}/Simple.png");

                using (PixelAccessor<Rgba32> sourcePixels = image.Lock())
                {
                    Assert.Equal(Rgba32.HotPink, sourcePixels[10, 10]);

                    Assert.Equal(Rgba32.HotPink, sourcePixels[200, 150]);

                    Assert.Equal(Rgba32.HotPink, sourcePixels[50, 300]);


                    Assert.Equal(Rgba32.HotPink, sourcePixels[37, 85]);

                    Assert.Equal(Rgba32.HotPink, sourcePixels[93, 85]);

                    Assert.Equal(Rgba32.HotPink, sourcePixels[65, 137]);

                    Assert.Equal(Rgba32.Blue, sourcePixels[2, 2]);

                    //inside hole
                    Assert.Equal(Rgba32.Blue, sourcePixels[57, 99]);

                    //inside shape
                    Assert.Equal(Rgba32.Blue, sourcePixels[100, 192]);
                }
            }
        }

        [Fact]
        public void ImageShouldBeOverlayedByPolygonOutlineNoOverlapping()
        {
            string path = TestEnvironment.CreateOutputDirectory("Drawing", "LineComplexPolygon");
            Polygon simplePath = new Polygon(new LinearLineSegment(
                            new Vector2(10, 10),
                            new Vector2(200, 150),
                            new Vector2(50, 300)));

            Polygon hole1 = new Polygon(new LinearLineSegment(
                            new Vector2(207, 25),
                            new Vector2(263, 25),
                            new Vector2(235, 57)));

            using (Image<Rgba32> image = new Image<Rgba32>(500, 500))
            {
                image.Mutate(x => x
                    .BackgroundColor(Rgba32.Blue)
                    .Draw(Rgba32.HotPink, 5, simplePath.Clip(hole1)));
                image.Save($"{path}/SimpleVanishHole.png");

                using (PixelAccessor<Rgba32> sourcePixels = image.Lock())
                {
                    Assert.Equal(Rgba32.HotPink, sourcePixels[10, 10]);

                    Assert.Equal(Rgba32.HotPink, sourcePixels[200, 150]);

                    Assert.Equal(Rgba32.HotPink, sourcePixels[50, 300]);


                    //Assert.Equal(Color.HotPink, sourcePixels[37, 85]);

                    //Assert.Equal(Color.HotPink, sourcePixels[93, 85]);

                    //Assert.Equal(Color.HotPink, sourcePixels[65, 137]);

                    Assert.Equal(Rgba32.Blue, sourcePixels[2, 2]);

                    //inside hole
                    Assert.Equal(Rgba32.Blue, sourcePixels[57, 99]);

                    //inside shape
                    Assert.Equal(Rgba32.Blue, sourcePixels[100, 192]);
                }
            }
        }


        [Fact]
        public void ImageShouldBeOverlayedByPolygonOutlineOverlapping()
        {
            string path = TestEnvironment.CreateOutputDirectory("Drawing", "LineComplexPolygon");
            Polygon simplePath = new Polygon(new LinearLineSegment(
                            new Vector2(10, 10),
                            new Vector2(200, 150),
                            new Vector2(50, 300)));

            Polygon hole1 = new Polygon(new LinearLineSegment(
                            new Vector2(37, 85),
                            new Vector2(130, 40),
                            new Vector2(65, 137)));

            using (Image<Rgba32> image = new Image<Rgba32>(500, 500))
            {
                image.Mutate(x => x
                    .BackgroundColor(Rgba32.Blue)
                    .Draw(Rgba32.HotPink, 5, simplePath.Clip(hole1)));
                image.Save($"{path}/SimpleOverlapping.png");

                using (PixelAccessor<Rgba32> sourcePixels = image.Lock())
                {
                    Assert.Equal(Rgba32.HotPink, sourcePixels[10, 10]);

                    Assert.Equal(Rgba32.HotPink, sourcePixels[200, 150]);

                    Assert.Equal(Rgba32.HotPink, sourcePixels[50, 300]);

                    Assert.Equal(Rgba32.Blue, sourcePixels[130, 41]);

                    Assert.Equal(Rgba32.Blue, sourcePixels[2, 2]);

                    //inside hole
                    Assert.Equal(Rgba32.Blue, sourcePixels[57, 99]);

                    //inside shape
                    Assert.Equal(Rgba32.Blue, sourcePixels[100, 192]);
                }
            }
        }


        [Fact]
        public void ImageShouldBeOverlayedByPolygonOutlineDashed()
        {
            string path = TestEnvironment.CreateOutputDirectory("Drawing", "LineComplexPolygon");
            Polygon simplePath = new Polygon(new LinearLineSegment(
                            new Vector2(10, 10),
                            new Vector2(200, 150),
                            new Vector2(50, 300)));

            Polygon hole1 = new Polygon(new LinearLineSegment(
                            new Vector2(37, 85),
                            new Vector2(93, 85),
                            new Vector2(65, 137)));

            using (Image<Rgba32> image = new Image<Rgba32>(500, 500))
            {
                image.Mutate(x => x
                    .BackgroundColor(Rgba32.Blue)
                    .Draw(Pens.Dash(Rgba32.HotPink, 5), simplePath.Clip(hole1)));
                image.Save($"{path}/Dashed.png");
            }
        }


        [Fact]
        public void ImageShouldBeOverlayedPolygonOutlineWithOpacity()
        {
            string path = TestEnvironment.CreateOutputDirectory("Drawing", "LineComplexPolygon");
            Polygon simplePath = new Polygon(new LinearLineSegment(
                            new Vector2(10, 10),
                            new Vector2(200, 150),
                            new Vector2(50, 300)));

            Polygon hole1 = new Polygon(new LinearLineSegment(
                            new Vector2(37, 85),
                            new Vector2(93, 85),
                            new Vector2(65, 137)));
            Rgba32 color = new Rgba32(Rgba32.HotPink.R, Rgba32.HotPink.G, Rgba32.HotPink.B, 150);

            using (Image<Rgba32> image = new Image<Rgba32>(500, 500))
            {
                image.Mutate(x => x
                    .BackgroundColor(Rgba32.Blue)
                    .Draw(color, 5, simplePath.Clip(hole1)));
                image.Save($"{path}/Opacity.png");

                //shift background color towards forground color by the opacity amount
                Rgba32 mergedColor = new Rgba32(Vector4.Lerp(Rgba32.Blue.ToVector4(), Rgba32.HotPink.ToVector4(), 150f / 255f));

                using (PixelAccessor<Rgba32> sourcePixels = image.Lock())
                {
                    Assert.Equal(mergedColor, sourcePixels[10, 10]);

                    Assert.Equal(mergedColor, sourcePixels[200, 150]);

                    Assert.Equal(mergedColor, sourcePixels[50, 300]);


                    Assert.Equal(mergedColor, sourcePixels[37, 85]);

                    Assert.Equal(mergedColor, sourcePixels[93, 85]);

                    Assert.Equal(mergedColor, sourcePixels[65, 137]);

                    Assert.Equal(Rgba32.Blue, sourcePixels[2, 2]);

                    //inside hole
                    Assert.Equal(Rgba32.Blue, sourcePixels[57, 99]);


                    //inside shape
                    Assert.Equal(Rgba32.Blue, sourcePixels[100, 192]);
                }
            }
        }
    }
}