#pragma once

#include <J3ML/Geometry/Common.h>
#include <J3ML/LinearAlgebra.h>

namespace J3ML::Geometry
{
    class Triangle
    {
    public:
        Vector3 V0;
        Vector3 V1;
        Vector3 V2;

        bool Intersects(const AABB& aabb) const;
        bool Intersects(const Capsule& capsule) const;
        AABB BoundingAABB() const;

        bool Contains(const Vector3&) const;

        void ProjectToAxis(const Vector3 &axis, float &dMin, float &dMax) const;


        static float IntersectLineTri(const Vector3 &linePos, const Vector3 &lineDir, const Vector3 &v0, const Vector3 &v1,
                               const Vector3 &v2, float &u, float &v);

        /// Computes the closest point on the edge of this triangle to the given object.
        /** @param outU [out] If specified, receives the barycentric U coordinate of the returned point (in the UV convention).
                This pointer may be null.
            @param outV [out] If specified, receives the barycentric V coordinate of the returned point (in the UV convention).
                This pointer may be null.
            @param outD [out] If specified, receives the distance along the line of the closest point on the line to the edge of this triangle.
            @return The closest point on the edge of this triangle to the given object.
            @todo Add ClosestPointToTriangleEdge(Point/Ray/Triangle/Plane/Polygon/Circle/Disk/AABB/OBB/Sphere/Capsule/Frustum/Polyhedron).
            @see Distance(), Contains(), Intersects(), ClosestPointToTriangleEdge(), Line::GetPoint. */
        Vector3 ClosestPointToTriangleEdge(const Line &line, float *outU, float *outV, float *outD) const;
        Vector3 ClosestPointToTriangleEdge(const LineSegment &lineSegment, float *outU, float *outV, float *outD) const;

        Vector3 ClosestPoint(const LineSegment &lineSegment, Vector3 *otherPt = 0) const;
        /// Returns the point at the given barycentric coordinates.
        /** This function computes the vector space point at the given barycentric coordinates.
            @param uvw The barycentric UVW coordinate triplet. The condition u+v+w == 1 should hold for the input coordinate.
                If 0 <= u,v,w <= 1, the returned point lies inside this triangle.
            @return u*a + v*b + w*c. */
        Vector3 Point(const Vector3 &uvw) const;
        Vector3 Point(float u, float v, float w) const;
        /** These functions are an alternate form of Point(u,v,w) for the case when the barycentric coordinates are
		represented as a (u,v) pair and not as a (u,v,w) triplet. This function is provided for convenience
		and effectively just computes Point(1-u-v, u, v).
		@param uv The barycentric UV coordinates. If 0 <= u,v <= 1 and u+v <= 1, then the returned point lies inside
			this triangle.
		@return a + (b-a)*u + (c-a)*v.
		@see BarycentricUV(), BarycentricUVW(), BarycentricInsideTriangle(). */
        Vector3 Point(const Vector2 &uv) const;
        Vector3 Point(float u, float v) const;

        /// Expresses the given point in barycentric (u,v,w) coordinates.
        /** @note There are two different conventions for representing barycentric coordinates. One uses
                a (u,v,w) triplet with the equation pt == u*a + v*b + w*c, and the other uses a (u,v) pair
                with the equation pt == a + u*(b-a) + v*(c-a). These two are equivalent. Use the mappings
                (u,v) -> (1-u-v, u, v) and (u,v,w)->(v,w) to convert between these two representations.
            @param point The point of the vector space to express in barycentric coordinates. This point should
                lie in the plane formed by this triangle.
            @return The factors (u,v,w) that satisfy the weighted sum equation point == u*a + v*b + w*c.
            @see BarycentricUV(), BarycentricInsideTriangle(), Point(), http://mathworld.wolfram.com/BarycentricCoordinates.html */
        Vector3 BarycentricUVW(const Vector3 &point) const;

        /// Expresses the given point in barycentric (u,v) coordinates.
        /** @note There are two different conventions for representing barycentric coordinates. One uses
                a (u,v,w) triplet with the equation pt == u*a + v*b + w*c, and the other uses a (u,v) pair
                with the equation pt == a + u*(b-a) + v*(c-a). These two are equivalent. Use the mappings
                (u,v) -> (1-u-v, u, v) and (u,v,w)->(v,w) to convert between these two representations.
            @param point The point to express in barycentric coordinates. This point should lie in the plane
                formed by this triangle.
            @return The factors (u,v) that satisfy the weighted sum equation point == a + u*(b-a) + v*(c-a).
            @see BarycentricUVW(), BarycentricInsideTriangle(), Point(). */
        Vector2 BarycentricUV(const Vector3 &point) const;


        Vector3 ClosestPoint(const Vector3 &p) const;

        Plane PlaneCCW() const;

        Plane PlaneCW() const;

        Vector3 Vertex(int i) const;

        LineSegment Edge(int i) const;
    };


}