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

namespace Blacklight.Core.UnitTests.Drawables
{
    public class ModelToWorldTests : TestFixture
    {
        public void DefaultAnchor_IsCenter()
        {
            AffineMatrix matrix = Rectangle.ModelToWorld(new Vector(10, 20), position: new Vector(100, 200));
            CheckEqual(new Vector(100, 200), matrix.TransformPoint(Rectangle.Center));
        }

        public void ZeroAngle_CenterAnchor_PinsFullMatrix()
        {
            var matrix = Rectangle.ModelToWorld(
                size: new Vector(10, 20), position: new Vector(100, 200));

            CheckEqual(new Vector(100, 200), matrix.TransformPoint(Rectangle.Center));
            CheckEqual(new Vector(105, 200), matrix.TransformPoint(new Vector(1, 0)));
            CheckEqual(new Vector(95,  200), matrix.TransformPoint(new Vector(-1, 0)));
            CheckEqual(new Vector(100, 210), matrix.TransformPoint(new Vector(0, 1)));
            CheckEqual(new Vector(100, 190), matrix.TransformPoint(new Vector(0, -1)));
        }

        public void ZeroAngle_TopLeftAnchor_CornersMapCorrectly()
        {
            var matrix = Rectangle.ModelToWorld(
                new Vector(10, 20), position: new Vector(100, 200), anchor: Rectangle.TopLeft);

            CheckEqual(new Vector(100, 200), matrix.TransformPoint(Rectangle.TopLeft));
            CheckEqual(new Vector(110, 200), matrix.TransformPoint(Rectangle.TopRight));
            CheckEqual(new Vector(110, 220), matrix.TransformPoint(Rectangle.BottomRight));            
            CheckEqual(new Vector(100, 220), matrix.TransformPoint(Rectangle.BottomLeft));
        }

        public void NinetyDegreeRotation_CenterAnchor_PinsFullMatrix()
        {
            var matrix = Rectangle.ModelToWorld(
                new Vector(10, 20), position: new Vector(100, 200), angle: Math.PI / 2);

            CheckEqual(new Vector(100, 200), matrix.TransformPoint(Rectangle.Center));
            CheckEqual(new Vector(100, 205), matrix.TransformPoint(new Vector(1, 0)));
            CheckEqual(new Vector(90,  200), matrix.TransformPoint(new Vector(0, 1)));
        }

        public void NinetyDegreeRotation_TopLeftAnchor_AnchorMapsToPosition()
        {
            var matrix = Rectangle.ModelToWorld(
                new Vector(10, 20), position: new Vector(100, 200),
                angle: Math.PI / 2, anchor: Rectangle.TopLeft);

            CheckEqual(new Vector(100, 200), matrix.TransformPoint(Rectangle.TopLeft));
        }

        public void FortyFiveDegreeRotation_NonSquare_PinsOffAxisTerms()
        {
            Scalar angle = Math.PI / 4;
            Scalar cos = Math.Cos(angle);
            Scalar sin = Math.Sin(angle);
            var matrix = Rectangle.ModelToWorld(
                new Vector(12, 8), position: new Vector(0, 0), angle: angle);

            CheckEqual(new Vector(6 * cos,  6 * sin), matrix.TransformPoint(new Vector(1, 0)));
            CheckEqual(new Vector(-4 * sin, 4 * cos), matrix.TransformPoint(new Vector(0, 1)));
        }

        public void NegativeWidth_FlipsXAxis()
        {
            var matrix = Rectangle.ModelToWorld(new Vector(-10, 20), position: new Vector(100, 200));

            CheckEqual(new Vector(100, 200), matrix.TransformPoint(Rectangle.Center));
            CheckEqual(new Vector(95,  200), matrix.TransformPoint(new Vector(1, 0)));
            CheckEqual(new Vector(105, 200), matrix.TransformPoint(new Vector(-1, 0)));
        }

        public void AllNonDefaultValues()
        {
            Scalar angle = Math.PI / 4;
            Scalar cos = Math.Cos(angle);
            Scalar sin = Math.Sin(angle);
            var matrix = Rectangle.ModelToWorld(
                new Vector(12, 8), position: new Vector(100, 200),
                angle: angle, anchor: Rectangle.TopLeft);

            CheckEqual(new Vector(100, 200), matrix.TransformPoint(Rectangle.TopLeft));
            CheckEqual(new Vector(100 + 12 * cos, 200 + 12 * sin), matrix.TransformPoint(new Vector(1, -1)));
            CheckEqual(new Vector(100 - 8 * sin,  200 + 8 * cos), matrix.TransformPoint(new Vector(-1, 1)));
        }
    }
}