using Azimuth;
using Blacklight.Core.Drawables;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using UnitTestSharp;

namespace Blacklight.Core.UnitTests.Drawables
{
    public class EllipseTests : TestFixture
    {
        public void DefaultPosition_IsOrigin()
        {
            var matrix = Ellipse.ModelToWorld(new Vector(10, 20));
            CheckEqual(new Vector(0, 0), matrix.TransformPoint(Vector.Zero));
        }

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

            CheckEqual(new Vector(100, 200), matrix.TransformPoint(Vector.Zero));
            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 NinetyDegreeRotation_PinsFullMatrix()
        {
            var matrix = Ellipse.ModelToWorld(new Vector(10, 20), position: new Vector(100, 200), angle: Math.PI / 2);

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

        public void PositiveAngle_IsCounterClockwise()
        {
            var matrix = Ellipse.ModelToWorld(new Vector(10, 10), position: new Vector(0, 0), angle: Math.PI / 2);

            CheckEqual(new Vector(0, 5),  matrix.TransformPoint(new Vector(1, 0)));
            CheckEqual(new Vector(-5, 0), matrix.TransformPoint(new Vector(0, 1)));
        }

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

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

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

            CheckEqual(new Vector(100, 200), matrix.TransformPoint(Vector.Zero));
            CheckEqual(new Vector(100 + 6 * cos, 200 + 6 * sin), matrix.TransformPoint(new Vector(1, 0)));
            CheckEqual(new Vector(100 - 4 * sin, 200 + 4 * cos), matrix.TransformPoint(new Vector(0, 1)));
        }
    }
}