using Azimuth;
using Blacklight.Core.Drawables;
using System;
using UnitTestSharp;

namespace Blacklight.Core.UnitTests
{
    public class EntityTests : TestFixture
    {
        static Vector TranslationOf<T>(Entity<T> entity) where T : IDrawable =>
            entity.modelToWorld.TransformPoint(Vector.Zero);

        public class CtorTests : TestFixture
        {
            public void KeepsTheDrawableAndTransform()
            {
                var entity = new Entity<Sprite>(
                    new Sprite { Additiveness = 1 }, AffineMatrix.BuildFromTranslation(new Vector(3, 0)));

                CheckEqual((Scalar)1, entity.drawable.Additiveness);
                CheckEqual(new Vector(3, 0), TranslationOf(entity));
            }

            public void ANullReferenceDrawableThrows()
            {
                CheckThrow<ArgumentNullException>();
                new Entity<Collage>(null, AffineMatrix.Identity);
            }

            public void Rebuild_KeepsTheDrawableButTakesTheNewTransform()
            {
                var original = new Entity<Sprite>(
                    new Sprite { Additiveness = 1 }, AffineMatrix.BuildFromTranslation(new Vector(3, 0)));

                var rebuilt = new Entity<Sprite>(original, AffineMatrix.BuildFromTranslation(new Vector(9, 0)));

                CheckEqual((Scalar)1, rebuilt.drawable.Additiveness);
                CheckEqual(new Vector(9, 0), TranslationOf(rebuilt));
            }
        }
    }
}