using System.Collections.Generic;
using Chernobyl.Mathematics.Vectors;
using NUnit.Framework;

namespace Chernobyl.Mathematics.Movement
{
    [TestFixture, Description("A set of tests for verifying that the " + 
        "MatrixTransform works as expected.")]
    public class MatrixTransformTests : TransformTests
    {
        [Test, Description("Tests the MatrixTransform.MatrixTransform() " + 
            "constructor to ensure it sets the proper ITransform.LocalMatrix " + 
            "value.")]
        public void DefaultConstructorTest()
        {
            MatrixTransform transform = new MatrixTransform();

            Assert.AreEqual(Matrix4.Identity, transform.LocalMatrix,
                "ITransform.LocalMatrix was not set to the expected value.");
        }

        [Test, Description("Tests the MatrixTransform.MatrixTransform(ref Matrix4) " + 
            "constructor to ensure it sets the proper ITransform.LocalMatrix value.")]
        public void ConstructorMatrix4Test()
        {
            Matrix4 matrix = new Matrix4(Vector4.UnitZ, Vector4.UnitX, Vector4.UnitW, Vector4.UnitX);
            MatrixTransform transform = new MatrixTransform(ref matrix);

            Assert.AreEqual(matrix, transform.LocalMatrix,
                "ITransform.LocalMatrix was not set to the expected value.");
        }

        [Test, Description("Tests the MatrixTransform.MatrixTransform(IList<ITransform>) " +
            "constructor to ensure it sets the proper ITransform.TransformChildren " +
            "value.")]
        public void ConstructorIListTest()
        {
            IList<ITransform> children = new List<ITransform>(new[] {new MatrixTransform()});
            MatrixTransform transform = new MatrixTransform(children);

            Assert.AreEqual(children, transform.TransformChildren,
                "ITransform.TransformChildren was not set to the expected value.");
        }

        [Test, Description("Tests the MatrixTransform.MatrixTransform(ref Matrix4, IList<ITransform>) " +
            "constructor to ensure it sets the proper ITransform.LocalMatrix and " +
            "ITransform.TransformChildren values.")]
        public void ConstructorMatrix4IListTest()
        {
            Matrix4 matrix = new Matrix4(Vector4.UnitZ, Vector4.UnitX, Vector4.UnitW, Vector4.UnitX);
            IList<ITransform> children = new List<ITransform>(new[] { new MatrixTransform() });
            MatrixTransform transform = new MatrixTransform(ref matrix, children);

            Assert.AreEqual(matrix, transform.LocalMatrix,
                "ITransform.LocalMatrix was not set to the expected value.");
            Assert.AreEqual(children, transform.TransformChildren,
                "ITransform.TransformChildren was not set to the expected value.");
        }

        protected override ITransform CreateTransform()
        {
            return new MatrixTransform();
        }
    }
}