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

namespace Annulus.UnitTests.DiscreteCollisionDetection
{
    public class LinePointTests : UnitTestSharp.TestFixture
    {
        public class FractionAlongLineTests : UnitTestSharp.TestFixture
        {
            public void Basic()
            {
                Vector pt = new Vector(0, 0);

                var line = new Line
                {
                    From = new Vector(-1, 0),
                    To = new Vector(1, 0),
                };

                Scalar t = LinePoint.FractionAlongLine(line, pt);

                CheckEqual(0.5, t);
            }

            public void Perpindicular()
            {
                Vector pt = new Vector(0, 7);

                var line = new Line
                {
                    From = new Vector(-1, 0),
                    To = new Vector(1, 0),
                };

                Scalar t = LinePoint.FractionAlongLine(line, pt);

                CheckEqual(0.5, t);
            }

            public void Infinity_Perp()
            {
                Vector pt = new Vector(0, Scalar.PositiveInfinity);

                var line = new Line
                {
                    From = new Vector(-1, 0),
                    To = new Vector(1, 0),
                };

                Scalar t = LinePoint.FractionAlongLine(line, pt);

                Check(Scalar.IsNaN(t));
            }

            public void Infinity_Parallel()
            {
                Vector pt = new Vector(Scalar.PositiveInfinity, 0);

                var line = new Line
                {
                    From = new Vector(-1, 0),
                    To = new Vector(1, 0),
                };

                Scalar t = LinePoint.FractionAlongLine(line, pt);

                CheckEqual(Scalar.PositiveInfinity, t);
            }

            public void Line_Infinity()
            {
                Vector pt = new Vector(0, 0);

                var line = new Line
                {
                    From = new Vector(Scalar.NegativeInfinity, 0),
                    To = new Vector(Scalar.PositiveInfinity, 0),
                };

                Scalar t = LinePoint.FractionAlongLine(line, pt);

                Check(Scalar.IsNaN(t));
            }
        }

        public class DistanceSquaredTests : TestFixture
        {
            public void Basic()
            {
                Vector point = new Vector(0, 1);

                var line = new Line
                {
                    From = new Vector(-1, 0),
                    To = new Vector(1, 0),
                };

                CheckEqual(1, LinePoint.DistanceSquared(line, point));
            }

            public void LongDistance()
            {
                Vector point = new Vector(0, 3);

                var line = new Line
                {
                    From = new Vector(-1, 0),
                    To = new Vector(1, 0),
                };

                CheckEqual(9, LinePoint.DistanceSquared(line, point));
            }

            public void OnLine()
            {
                Vector point = new Vector(0, 0);

                var line = new Line
                {
                    From = new Vector(-1, 0),
                    To = new Vector(1, 0),
                };

                CheckEqual(0, LinePoint.DistanceSquared(line, point));
            }

            public void DegenerateLine()
            {
                Vector point = new Vector(1, 0);

                var line = new Line
                {
                    From = new Vector(-1, 0),
                    To = new Vector(-1, 0),
                };

                CheckEqual(4, LinePoint.DistanceSquared(line, point));
            }

            public void AllPointsCoincident()
            {
                Vector point = new Vector(-1, 0);

                var line = new Line
                {
                    From = new Vector(-1, 0),
                    To = new Vector(-1, 0),
                };

                CheckEqual(0, LinePoint.DistanceSquared(line, point));
            }
        }
    }
}