#pragma once

#ifdef _WIN32
    #define INTERSECTION_API __declspec(dllexport)
#else
    #define INTERSECTION_API
#endif

#include "Geometry.h"
#include <numeric>
#include <algorithm>
#include <vector>
#include <cstddef>
#include <iostream>       // std::cerr
#include <stdexcept>      // std::length_error

extern "C" struct INTERSECTION_API TriangleSegmentIntersectRes
{
    bool hit;
    float t;
    TriangleSegmentIntersectRes(bool h, float tt);
};

INTERSECTION_API
TriangleSegmentIntersectRes triangleSegmentIntersection(const LineSegment &segment, const Vec3f &a, const Vec3f &b, const Vec3f &c);

extern "C" class INTERSECTION_API BVHNode
{
public:
    size_t left;
    size_t right;
    size_t parent;
    AABB boundingBox;

    BVHNode(size_t l, size_t r, size_t p, const AABB &aabb);
    BVHNode();
};

extern "C" class INTERSECTION_API BVH_intersection
{
public:
    const Mesh &mesh;
    std::vector<Vec3f> faceCenters;
    std::vector<BVHNode> nodes;

    BVH_intersection(const Mesh &mesh_);

    size_t
    dfsBuild(std::vector<size_t> &indicesList, AABB aabb, size_t &nowIdx);
    bool intersectWithLineSegment(const LineSegment &lineSegment) const;

private:
    AABB computeAABB(const std::vector<size_t> &indices);
    bool recursiveLineSegIntersection(const LineSegment &lineSegment, size_t nodeIdx) const;

    void nth(std::vector<size_t> &indicesList, size_t kth, int longAxis);
    void recursiveChoose(std::vector<size_t> &indicesList, size_t begin, size_t end, size_t kth, int longAxis);
};