using System.Reflection;
using Annulus;
using Blacklight.Core;
using UnitTestSharp;
using DrawingPoint = System.Drawing.Point;
using DrawingSize = System.Drawing.Size;

namespace Glass.Blacklight.UnitTests
{
    // CursorSheet.png is 8 by 4, red in its left four columns and blue in its right four.
    public class SpriteCursorTests : TestFixture
    {
        private const string Sheet = "Glass.Blacklight.UnitTests.CursorSheet.png";

        [SpriteSheet(spriteSizeX: 4, spriteSizeY: 4, borderSize: 0, Sheet)]
        public sealed class FlatSheet
        {
        }

        [SpriteSheet(spriteSizeX: 4, spriteSizeY: 4, borderSize: 0, Sheet, gridOriginX: 4)]
        public sealed class OffsetSheet
        {
        }

        [SpriteSheet(spriteSizeX: 2, spriteSizeY: 4, borderSize: 2, Sheet)]
        public sealed class BorderedSheet
        {
        }

        private static readonly Assembly Art = typeof(SpriteCursorTests).Assembly;

        [IgnoreTest]
        private static DrawingPoint FirstPixel(CursorImage image)
        {
            return new DrawingPoint(image.Rgba[0], image.Rgba[2]);
        }

        public class ImageForTests : TestFixture
        {
            public void ACellOfAFlatSheet_CropsThatCell()
            {
                SpriteMaterial sprite = MaterialLibrary<FlatSheet>.CreateSprite(new Point(1, 0));

                CursorImage image = SpriteCursor.ImageFor(sprite, new Point(1, 2), scale: 1, Art);

                CheckEqual(new DrawingSize(4, 4), image.Size);
                CheckEqual(new DrawingPoint(0, 255), FirstPixel(image));
            }

            public void AGridOrigin_ShiftsTheCropIntoTheSheet()
            {
                SpriteMaterial sprite = MaterialLibrary<OffsetSheet>.CreateSprite(new Point(0, 0));

                CursorImage image = SpriteCursor.ImageFor(sprite, new Point(0, 0), scale: 1, Art);

                CheckEqual(new DrawingPoint(0, 255), FirstPixel(image));
            }

            public void ABorderBetweenCells_PushesLaterCellsAlongByItsWidth()
            {
                SpriteMaterial first = MaterialLibrary<BorderedSheet>.CreateSprite(new Point(0, 0));
                SpriteMaterial second = MaterialLibrary<BorderedSheet>.CreateSprite(new Point(1, 0));

                CheckEqual(
                    new DrawingPoint(255, 0), FirstPixel(SpriteCursor.ImageFor(first, new Point(0, 0), 1, Art)));
                CheckEqual(
                    new DrawingPoint(0, 255), FirstPixel(SpriteCursor.ImageFor(second, new Point(0, 0), 1, Art)));
            }

            public void AScale_EnlargesThePixelsAndTheHotspot()
            {
                SpriteMaterial sprite = MaterialLibrary<FlatSheet>.CreateSprite(new Point(0, 0));

                CursorImage image = SpriteCursor.ImageFor(sprite, new Point(1, 2), scale: 3, Art);

                CheckEqual(new DrawingSize(12, 12), image.Size);
                CheckEqual(new DrawingPoint(3, 6), image.Hotspot);
            }
        }

        public class InstanceImageForTests : TestFixture
        {
            public void UsesTheCursorsOwnSpriteAndHotspot()
            {
                SpriteMaterial sprite = MaterialLibrary<FlatSheet>.CreateSprite(new Point(1, 0));
                var cursor = new SpriteCursor(sprite, new Point(1, 2));

                CursorImage image = cursor.ImageFor(scale: 2, Art);

                CheckEqual(new DrawingSize(8, 8), image.Size);
                CheckEqual(new DrawingPoint(2, 4), image.Hotspot);
                CheckEqual(new DrawingPoint(0, 255), FirstPixel(image));
            }
        }

        public class CtorTests : TestFixture
        {
            public void KeepsTheSpriteAndHotspot()
            {
                SpriteMaterial sprite = MaterialLibrary<FlatSheet>.CreateSprite(new Point(0, 0));
                var cursor = new SpriteCursor(sprite, new Point(5, 6));

                CheckEqual(sprite, cursor.Sprite);
                CheckEqual(new Point(5, 6), cursor.Hotspot);
            }
        }
    }
}