using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using Azimuth;
using Annulus;
using Annulus.DiscreteCollisionDetection;

namespace Annulus.UnitTests.DiscreteCollisionDetection
{
    public class LineRayTests : UnitTestSharp.TestFixture
    {
        public void Basic()
        {
            var A = new Line
            {
                From = new Vector(0, -1),
                To = new Vector(0, 1),
            };

            var B = new Ray
            {
                From = new Vector(-1, 0),
                Direction = new Vector(2, 0),
            };

            Scalar t1;
            var result = LineRay.FindIntersection(A, B, out t1);

            CheckEqual(0.5, t1);
            CheckEqual(LineLine.Result.Intersecting, result);
        }

        public void OneDegenerate_First()
        {
            var A = new Line
            {
                From = new Vector(1, 0),
                To = new Vector(1, 0),
            };

            var B = new Ray
            {
                From = new Vector(-1, 0),
                Direction = new Vector(2, 0),
            };

            Scalar t1;
            var result = LineRay.FindIntersection(A, B, out t1);

            Check(Scalar.IsNaN(t1));
            CheckEqual(LineLine.Result.Degenerate, result);
        }

        public void OneDegenerate_Second()
        {
            var A = new Line
            {
                From = new Vector(0, -1),
                To = new Vector(0, 1),
            };

            var B = new Ray
            {
                From = new Vector(0, 0),
                Direction = new Vector(0, 0),
            };

            Scalar t1;
            var result = LineRay.FindIntersection(A, B, out t1);

            Check(Scalar.IsNaN(t1));
            CheckEqual(LineLine.Result.Degenerate, result);
        }

        public void Parallel_Identical()
        {
            var A = new Line
            {
                From = new Vector(0, -1),
                To = new Vector(0, 1),
            };

            var B = new Ray
            {
                From = new Vector(0, -1),
                Direction = new Vector(0, 1),
            };

            Scalar t1;
            var result = LineRay.FindIntersection(A, B, out t1);

            Check(Scalar.IsNaN(t1));
            CheckEqual(LineLine.Result.Parallel, result);
        }

        public void Parallel_NonIdentical()
        {
            var A = new Line
            {
                From = new Vector(1, -2),
                To = new Vector(1, 2),
            };

            var B = new Ray
            {
                From = new Vector(0, -1),
                Direction = new Vector(0, 2),
            };

            Scalar t1;
            var result = LineRay.FindIntersection(A, B, out t1);

            Check(Scalar.IsNaN(t1));
            CheckEqual(LineLine.Result.Parallel, result);
        }

        public void DoubleDegenerate()
        {
            var A = new Line
            {
                From = new Vector(1, 1),
                To = new Vector(1, 1),
            };

            var B = new Ray
            {
                From = new Vector(1, 1),
                Direction = new Vector(1, 1),
            };

            Scalar t1;
            var result = LineRay.FindIntersection(A, B, out t1);

            Check(Scalar.IsNaN(t1));
            CheckEqual(LineLine.Result.Degenerate, result);
        }

        public void Infinity_Parallel()
        {
            var A = new Line
            {
                From = new Vector(1, 0),
                To = new Vector(1, Scalar.PositiveInfinity),
            };

            var B = new Ray
            {
                From = new Vector(0, 1),
                Direction = new Vector(0, Scalar.PositiveInfinity),
            };

            Scalar t1;
            var result = LineRay.FindIntersection(A, B, out t1);

            Check(Scalar.IsNaN(t1));
            CheckEqual(LineLine.Result.Degenerate, result);
        }

        public void Infinity_Intersection()
        {
            var A = new Line
            {
                From = new Vector(1, 0),
                To = new Vector(1, Scalar.PositiveInfinity),
            };

            var B = new Ray
            {
                From = new Vector(0, 1),
                Direction = new Vector(Scalar.PositiveInfinity, 1),
            };

            Scalar t1;
            var result = LineRay.FindIntersection(A, B, out t1);

            Check(Scalar.IsNaN(t1));
            CheckEqual(LineLine.Result.Degenerate, result);
        }

        public void LineBehindRay()
        {
            var A = new Line
            {
                From = new Vector(1, 0),
                To = new Vector(1, -1),
            };

            var B = new Ray
            {
                From = new Vector(2, 0),
                Direction = new Vector(1, 0),
            };

            Scalar t1;
            var result = LineRay.FindIntersection(A, B, out t1);

            Check(Scalar.IsNaN(t1));
            CheckEqual(LineLine.Result.NonParallelNoIntersection, result);
        }
    }
}