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

namespace Annulus.UnitTests.DiscreteCollisionDetection
{
    public class TriangleTriangleTests : UnitTestSharp.TestFixture
    {
        public void Disparate()
        {
            var triangle1 = new Vector[]
            {
                new Vector(0, 0),
                new Vector(1, 0),
                new Vector(0, 1),
            };

            var triangle2 = new Vector[]
            {
                new Vector(3, 0),
                new Vector(4, 0),
                new Vector(3, 1),
            };

            CheckFalse(TriangleTriangle.Intersects(triangle1, triangle2));
            CheckFalse(TriangleTriangle.Intersects(triangle2, triangle1));
        }

        public void SmallerTriangleInsideLargerTriangle()
        {
            var triangle1 = new Vector[]
            {
                new Vector(-1, -1),
                new Vector(1, -1),
                new Vector(0, 1),
            };

            var triangle2 = new Vector[]
            {
                new Vector(0, -.75),
                new Vector(-.25, 0),
                new Vector(.25, 0),
            };

            CheckTrue(TriangleTriangle.Intersects(triangle1, triangle2));
            CheckTrue(TriangleTriangle.Intersects(triangle2, triangle1));
        }

        public void SameTriangle()
        {
            var triangle1 = new Vector[]
            {
                new Vector(-1, -1),
                new Vector(1, -1),
                new Vector(0, 1),
            };

            var triangle2 = new Vector[]
            {
                new Vector(-1, -1),
                new Vector(1, -1),
                new Vector(0, 1),
            };

            CheckTrue(TriangleTriangle.Intersects(triangle1, triangle2));
            CheckTrue(TriangleTriangle.Intersects(triangle2, triangle1));
        }

        public void DisparateColinearEdges()
        {
            var triangle1 = new Vector[]
            {
                new Vector(-1, -1),
                new Vector(1, -1),
                new Vector(0, 1),
            };

            var triangle2 = new Vector[]
            {
                new Vector(2, -1),
                new Vector(4, -1),
                new Vector(2, 1),
            };

            CheckFalse(TriangleTriangle.Intersects(triangle1, triangle2));
            CheckFalse(TriangleTriangle.Intersects(triangle2, triangle1));
        }

        public void SimilarEdgeIntersecting()
        {
            var triangle1 = new Vector[]
            {
                new Vector(-1, -1),
                new Vector(1, -1),
                new Vector(0, 1),
            };

            var triangle2 = new Vector[]
            {
                new Vector(-1, -1),
                new Vector(1, -1),
                new Vector(0, 0),
            };

            CheckTrue(TriangleTriangle.Intersects(triangle1, triangle2));
            CheckTrue(TriangleTriangle.Intersects(triangle2, triangle1));
        }

        public void SimilarEdgeGlancing()
        {
            var triangle1 = new Vector[]
            {
                new Vector(-1, -1),
                new Vector(1, -1),
                new Vector(0, 1),
            };

            var triangle2 = new Vector[]
            {
                new Vector(-1, -1),
                new Vector(1, -1),
                new Vector(0, -1),
            };

            CheckFalse(TriangleTriangle.Intersects(triangle1, triangle2));
            CheckFalse(TriangleTriangle.Intersects(triangle2, triangle1));
        }

        public void SharedEdgeIntersecting()
        {
            var triangle1 = new Vector[]
            {
                new Vector(-1, -1),
                new Vector(1, -1),
                new Vector(0, 1),
            };

            var triangle2 = new Vector[]
            {
                new Vector(-0.5, -1),
                new Vector(0.5, -1),
                new Vector(0, 0),
            };

            CheckTrue(TriangleTriangle.Intersects(triangle1, triangle2));
            CheckTrue(TriangleTriangle.Intersects(triangle2, triangle1));
        }

        public void SharedEdgeGlancing()
        {
            var triangle1 = new Vector[]
            {
                new Vector(-1, -1),
                new Vector(1, -1),
                new Vector(0, 1),
            };

            var triangle2 = new Vector[]
            {
                new Vector(-0.5, -1),
                new Vector(0.5, -1),
                new Vector(0, -1),
            };

            CheckFalse(TriangleTriangle.Intersects(triangle1, triangle2));
            CheckFalse(TriangleTriangle.Intersects(triangle2, triangle1));
        }

        public void TwoOverlapingEdges()
        {
            var triangle1 = new Vector[]
            {
                new Vector(0, 0),
                new Vector(2, 0),
                new Vector(0, 1),
            };

            var triangle2 = new Vector[]
            {
                new Vector(0, 0),
                new Vector(1, 0),
                new Vector(0, 2),
            };

            CheckTrue(TriangleTriangle.Intersects(triangle1, triangle2));
            CheckTrue(TriangleTriangle.Intersects(triangle2, triangle1));
        }

        public void OneVertexInsideTheOther()
        {
            var triangle1 = new Vector[]
            {
                new Vector(-1, 0),
                new Vector(1, 0),
                new Vector(0, 1),
            };

            var triangle2 = new Vector[]
            {
                new Vector(-1, -2),
                new Vector(1, -2),
                new Vector(0, 0.5),
            };

            CheckTrue(TriangleTriangle.Intersects(triangle1, triangle2));
            CheckTrue(TriangleTriangle.Intersects(triangle2, triangle1));
        }

        public void EachContainingAVertex()
        {
            var triangle1 = new Vector[]
            {
                new Vector(-1, 0),
                new Vector(1, 0),
                new Vector(0, 1),
            };

            var triangle2 = new Vector[]
            {
                new Vector(-1, 2),
                new Vector(1, 2),
                new Vector(0, 0.5),
            };

            CheckTrue(TriangleTriangle.Intersects(triangle1, triangle2));
            CheckTrue(TriangleTriangle.Intersects(triangle2, triangle1));
        }

        public void Hexagram()
        {
            var triangle1 = new Vector[]
            {
                new Vector(-1, 0),
                new Vector(1, 0),
                new Vector(0, 2),
            };

            var triangle2 = new Vector[]
            {
                new Vector(-1, 1),
                new Vector(1, 1),
                new Vector(0, -1),
            };

            CheckTrue(TriangleTriangle.Intersects(triangle1, triangle2));
            CheckTrue(TriangleTriangle.Intersects(triangle2, triangle1));
        }

        public void OneEdgeInsideTheOther()
        {
            var triangle1 = new Vector[]
            {
                new Vector(-1, 0),
                new Vector(1, 0),
                new Vector(0, 2),
            };

            var triangle2 = new Vector[]
            {
                new Vector(-0.1, 0.1),
                new Vector(0.1, 0.2),
                new Vector(3, 3),
            };

            CheckTrue(TriangleTriangle.Intersects(triangle1, triangle2));
            CheckTrue(TriangleTriangle.Intersects(triangle2, triangle1));
        }

        public void OneEdgeInsideTheOther_OneOtherVertexInside()
        {
            var triangle1 = new Vector[]
            {
                new Vector(-1, 0),
                new Vector(1, 0),
                new Vector(0, 2),
            };

            var triangle2 = new Vector[]
            {
                new Vector(-0.1, 0.25),
                new Vector(0.1, 0.25),
                new Vector(0, 3),
            };

            CheckTrue(TriangleTriangle.Intersects(triangle1, triangle2));
            CheckTrue(TriangleTriangle.Intersects(triangle2, triangle1));
        }

        public void BothDegenerateSamePoint()
        {
            var triangle1 = new Vector[]
            {
                new Vector(0, 0),
                new Vector(0, 0),
                new Vector(0, 0),
            };

            var triangle2 = new Vector[]
            {
                new Vector(0, 0),
                new Vector(0, 0),
                new Vector(0, 0),
            };

            CheckFalse(TriangleTriangle.Intersects(triangle1, triangle2));
            CheckFalse(TriangleTriangle.Intersects(triangle2, triangle1));
        }

        public void BothDegenerateDifferentPoints()
        {
            var triangle1 = new Vector[]
            {
                new Vector(0, 0),
                new Vector(0, 0),
                new Vector(0, 0),
            };

            var triangle2 = new Vector[]
            {
                new Vector(1, 1),
                new Vector(1, 1),
                new Vector(1, 1),
            };

            CheckFalse(TriangleTriangle.Intersects(triangle1, triangle2));
            CheckFalse(TriangleTriangle.Intersects(triangle2, triangle1));
        }

        public void OneDegenerateInsideOther()
        {
            var triangle1 = new Vector[]
            {
                new Vector(0, 0),
                new Vector(0, 0),
                new Vector(0, 0),
            };

            var triangle2 = new Vector[]
            {
                new Vector(-1, -1),
                new Vector(1, -1),
                new Vector(0, 2),
            };

            CheckTrue(TriangleTriangle.Intersects(triangle1, triangle2));
            CheckTrue(TriangleTriangle.Intersects(triangle2, triangle1));
        }

        public void OneFlatInsideOther()
        {
            var triangle1 = new Vector[]
            {
                new Vector(-.25, -.75),
                new Vector(0, -.75),
                new Vector(.25, -.75),
            };

            var triangle2 = new Vector[]
            {
                new Vector(-1, -1),
                new Vector(1, -1),
                new Vector(0, 2),
            };

            CheckTrue(TriangleTriangle.Intersects(triangle1, triangle2));
            CheckTrue(TriangleTriangle.Intersects(triangle2, triangle1));
        }

        public void BothFlatSameLine()
        {
            var triangle1 = new Vector[]
            {
                new Vector(-.25, -.75),
                new Vector(0, -.75),
                new Vector(.25, -.75),
            };

            var triangle2 = new Vector[]
            {
                new Vector(-.25, -.75),
                new Vector(0, -.75),
                new Vector(.25, -.75),
            };

            CheckFalse(TriangleTriangle.Intersects(triangle1, triangle2));
            CheckFalse(TriangleTriangle.Intersects(triangle2, triangle1));
        }

        public void OneFlatOutsideOther()
        {
            var triangle1 = new Vector[]
            {
                new Vector(-.25, -.75),
                new Vector(0, -.75),
                new Vector(.25, -.75),
            };

            var triangle2 = new Vector[]
            {
                new Vector(10, 0),
                new Vector(12, 0),
                new Vector(11, 1),
            };

            CheckFalse(TriangleTriangle.Intersects(triangle1, triangle2));
            CheckFalse(TriangleTriangle.Intersects(triangle2, triangle1));
        }

        public void DegeneratePointOnFlatTriangle()
        {
            var triangle1 = new Vector[]
            {
                new Vector(-.25, -.75),
                new Vector(0, -.75),
                new Vector(.25, -.75),
            };

            var triangle2 = new Vector[]
            {
                new Vector(0, -.75),
                new Vector(0, -.75),
                new Vector(0, -.75),
            };

            CheckFalse(TriangleTriangle.Intersects(triangle1, triangle2));
            CheckFalse(TriangleTriangle.Intersects(triangle2, triangle1));
        }
    }
}