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

namespace Glass.Blacklight.UnitTests
{
    public class PageTextureCacheTests : TestFixture
    {
        private static readonly Assembly ThisAssembly = typeof(PageTextureCacheTests).Assembly;
        private static readonly Assembly OtherAssembly = typeof(string).Assembly;

        private static Texture NewTexture()
        {
            return new FontRendererTests.SizedTexture(new DrawingSize(64, 64));
        }

        public class GetOrCreateTests : TestFixture
        {
            public void FirstRequest_ReturnsWhatCreateMakes()
            {
                var cache = new PageTextureCache();
                Texture made = NewTexture();

                Texture returned = cache.GetOrCreate(ThisAssembly, "Fonts.Page_0.png", () => made);

                CheckTrue(ReferenceEquals(made, returned));
                CheckEqual(1, cache.Count);
            }

            public void RepeatRequest_ReturnsTheSameTextureWithoutCreatingAnother()
            {
                var cache = new PageTextureCache();
                Texture first = cache.GetOrCreate(ThisAssembly, "Fonts.Page_0.png", NewTexture);
                int created = 0;

                Texture second = cache.GetOrCreate(ThisAssembly, "Fonts.Page_0.png", () =>
                {
                    ++created;
                    return NewTexture();
                });

                CheckTrue(ReferenceEquals(first, second));
                CheckEqual(0, created);
                CheckEqual(1, cache.Count);
            }

            public void DifferentResources_GetTheirOwnTextures()
            {
                var cache = new PageTextureCache();

                Texture first = cache.GetOrCreate(ThisAssembly, "Fonts.Sans-16px_0.png", NewTexture);
                Texture second = cache.GetOrCreate(ThisAssembly, "Fonts.Sans-32px_0.png", NewTexture);

                CheckFalse(ReferenceEquals(first, second));
                CheckEqual(2, cache.Count);
            }

            public void SameResourceInDifferentAssemblies_GetsItsOwnTexturePerAssembly()
            {
                var cache = new PageTextureCache();

                Texture first = cache.GetOrCreate(ThisAssembly, "Fonts.Page_0.png", NewTexture);
                Texture second = cache.GetOrCreate(OtherAssembly, "Fonts.Page_0.png", NewTexture);

                CheckFalse(ReferenceEquals(first, second));
                CheckEqual(2, cache.Count);
            }

            public void NullAssembly_Throws()
            {
                var cache = new PageTextureCache();

                CheckThrow(typeof(ArgumentNullException));
                cache.GetOrCreate(null, "Fonts.Page_0.png", NewTexture);
            }

            public void NullResource_Throws()
            {
                var cache = new PageTextureCache();

                CheckThrow(typeof(ArgumentNullException));
                cache.GetOrCreate(ThisAssembly, null, NewTexture);
            }

            public void NullCreate_Throws()
            {
                var cache = new PageTextureCache();

                CheckThrow(typeof(ArgumentNullException));
                cache.GetOrCreate(ThisAssembly, "Fonts.Page_0.png", null);
            }

            public void ACreateThatThrows_LeavesNothingCached()
            {
                var cache = new PageTextureCache();

                try
                {
                    cache.GetOrCreate(ThisAssembly, "Fonts.Page_0.png", () => throw new InvalidOperationException());
                }
                catch (InvalidOperationException)
                {
                }

                CheckEqual(0, cache.Count);
            }
        }
    }
}