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

namespace Annulus.UnitTests.DiscreteCollisionDetection
{
    public class SegmentPointTests : UnitTestSharp.TestFixture
    {
        public class DistanceSquaredTests : UnitTestSharp.TestFixture
        {
            public void Basic()
            {
                Scalar distance = SegmentPoint.DistanceSquared(new Line
                {
                    From = new Vector(-10, 0),
                    To = new Vector(3, 0),
                }, new Vector(0, 3));

                CheckEqual(9, distance);
            }

            public void TooLeft()
            {
                Scalar distance = SegmentPoint.DistanceSquared(new Line
                {
                    From = new Vector(-1, 0),
                    To = new Vector(1, 0),
                }, new Vector(-3, 0));

                CheckEqual(4, distance);
            }

            public void TooRight()
            {
                Scalar distance = SegmentPoint.DistanceSquared(new Line
                {
                    From = new Vector(-1, 0),
                    To = new Vector(1, 0),
                }, new Vector(3, 0));

                CheckEqual(4, distance);
            }

            public void DegenerateLine_SamePoint()
            {
                Scalar distance = SegmentPoint.DistanceSquared(new Line
                {
                    From = new Vector(1, 0),
                    To = new Vector(1, 0),
                }, new Vector(1, 0));

                CheckEqual(0, distance);
            }

            public void DegenerateLine_DifferentPoint()
            {
                Scalar distance = SegmentPoint.DistanceSquared(new Line
                {
                    From = new Vector(1, 0),
                    To = new Vector(1, 0),
                }, new Vector(5, 0));

                CheckEqual(16, distance);
            }

            public void NaNs_Line()
            {
                Scalar distance = SegmentPoint.DistanceSquared(new Line
                {
                    From = new Vector(Scalar.NaN, 0),
                    To = new Vector(1, 0),
                }, new Vector(5, 0));

                Check(Scalar.IsNaN(distance));
            }

            public void NaNs_Point()
            {
                Scalar distance = SegmentPoint.DistanceSquared(new Line
                {
                    From = new Vector(2, 0),
                    To = new Vector(1, 0),
                }, new Vector(Scalar.NaN, 0));

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

        public class DistanceTests : UnitTestSharp.TestFixture
        {
            public void Basic()
            {
                Scalar distance = SegmentPoint.Distance(new Line
                {
                    From = new Vector(-10, 0),
                    To = new Vector(3, 0),
                }, new Vector(0, 3));

                CheckEqual(3, distance);
            }

            public void TooLeft()
            {
                Scalar distance = SegmentPoint.Distance(new Line
                {
                    From = new Vector(-1, 0),
                    To = new Vector(1, 0),
                }, new Vector(-3, 0));

                CheckEqual(2, distance);
            }

            public void TooRight()
            {
                Scalar distance = SegmentPoint.Distance(new Line
                {
                    From = new Vector(-1, 0),
                    To = new Vector(1, 0),
                }, new Vector(3, 0));

                CheckEqual(2, distance);
            }

            public void DegenerateLine_SamePoint()
            {
                Scalar distance = SegmentPoint.Distance(new Line
                {
                    From = new Vector(1, 0),
                    To = new Vector(1, 0),
                }, new Vector(1, 0));

                CheckEqual(0, distance);
            }

            public void DegenerateLine_DifferentPoint()
            {
                Scalar distance = SegmentPoint.Distance(new Line
                {
                    From = new Vector(1, 0),
                    To = new Vector(1, 0),
                }, new Vector(5, 0));

                CheckEqual(4, distance);
            }

            public void NaNs_Line()
            {
                Scalar distance = SegmentPoint.Distance(new Line
                {
                    From = new Vector(Scalar.NaN, 0),
                    To = new Vector(1, 0),
                }, new Vector(5, 0));

                Check(Scalar.IsNaN(distance));
            }

            public void NaNs_Point()
            {
                Scalar distance = SegmentPoint.Distance(new Line
                {
                    From = new Vector(2, 0),
                    To = new Vector(1, 0),
                }, new Vector(Scalar.NaN, 0));

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

        public class ClosestPointOnSegmentToPointTests : 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 = SegmentPoint.ClosestPointOnSegmentToPoint(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 = SegmentPoint.ClosestPointOnSegmentToPoint(line, pt);

                CheckEqual(0.5, t);
            }

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

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

                Scalar t = SegmentPoint.ClosestPointOnSegmentToPoint(line, pt);

                CheckEqual(1, t);
            }

            public void SmallFraction()
            {
                Vector pt = new Vector(-7, 7);

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

                Scalar t = SegmentPoint.ClosestPointOnSegmentToPoint(line, pt);

                CheckEqual(0, 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 = SegmentPoint.ClosestPointOnSegmentToPoint(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 = SegmentPoint.ClosestPointOnSegmentToPoint(line, pt);

                CheckEqual(1, 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 = SegmentPoint.ClosestPointOnSegmentToPoint(line, pt);

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