#ifndef RAYTRYCPP_KDTREE_H
#define RAYTRYCPP_KDTREE_H

#include "AABB.h"
#include "KDAxis.h"
#include "KDLeaf.h"
#include "KDNode.h"
#include "Triangle.h"
#include <random>
#include <vector>


namespace raytry::KD {

    typedef std::vector<std::pair<float, const Triangle *>> triangleValueVector;

    struct AxisData {
        AxisData() = default;
        ~AxisData() = default;

        AABB boundaries{};
        std::array<triangleValueVector, Z + 1> mins{triangleValueVector{}, triangleValueVector{}, triangleValueVector{}};
        std::array<triangleValueVector, Z + 1> maxs{triangleValueVector{}, triangleValueVector{}, triangleValueVector{}};
    };

    class Tree {
    public:
        Tree() = default;
        Tree(const Tree &);
        ~Tree() = default;
        Tree &operator=(Tree other);

        static Tree build(const std::vector<Triangle> &triangles);

        const std::vector<KD::Node> &getNodes();
        const std::vector<KD::Leaf> &getLeafs();
        const AABB &getBounds();

    private:
        static constexpr unsigned int maxDepth{7};
        static constexpr size_t randomSamples{101};
        static constexpr float traversalCost{5};

        static void insertSorted(triangleValueVector &sortedTriangles, float value, const Triangle &triangle);
        static void insertSortedReversed(triangleValueVector &sortedTriangles, float value, const Triangle &triangle);
        static float calculateCost(float costConstant, float bndMin, float bndMax, unsigned int count);
        static void separateAxisData(AxisData &data, std::array<triangleValueVector, Z + 1> &separatingData, std::array<triangleValueVector, Z + 1> &otherData, Axis axis, float tVal, bool separatorIsEnd);
        float probeBestT(const Axis &axis, const AxisData &data);
        unsigned int recursiveNodeBuild(unsigned int depthLeft, Axis axis, const AxisData &axisData);

        std::vector<KD::Node> nodes{};
        std::vector<KD::Leaf> leafs{};
        AABB boundaries{};
        std::random_device randomDevice{};
        std::mt19937 randomGenerator{randomDevice()};
        unsigned int randomProbes{0};
    };

}// namespace raytry::KD

#endif//RAYTRYCPP_KDTREE_H