#include "TriangulateWall.hpp"
#include "MTUtils.hpp"

namespace Slic3r {

//class Ring {
//    size_t idx = 0, nextidx = 1, startidx = 0, begin = 0, end = 0;
    
//public:
//    explicit Ring(size_t from, size_t to) : begin(from), end(to) { init(begin); }

//    size_t size() const { return end - begin; }
//    std::pair<size_t, size_t> pos() const { return {idx, nextidx}; }
//    bool is_lower() const { return idx < size(); }
    
//    void inc()
//    {
//        if (nextidx != startidx) nextidx++;
//        if (nextidx == end) nextidx = begin;
//        idx ++;
//        if (idx == end) idx = begin;
//    }
    
//    void init(size_t pos)
//    {
//        startidx = begin + (pos - begin) % size();
//        idx = startidx;
//        nextidx = begin + (idx + 1 - begin) % size();
//    }
    
//    bool is_finished() const { return nextidx == idx; }
//};

//template<class Sc>
//static Sc sq_dst(const Vec<3, Sc> &v1, const Vec<3, Sc>& v2)
//{
//    Vec<3, Sc> v = v1 - v2;
//    return v.x() * v.x() + v.y() * v.y() /*+ v.z() * v.z()*/;
//}

//template<class Sc>
//static Sc trscore(const Ring &                   onring,
//                  const Ring &                   offring,
//                  const std::vector<Vec<3, Sc>> &pts)
//{
//    Sc a = sq_dst(pts[onring.pos().first], pts[offring.pos().first]);
//    Sc b = sq_dst(pts[onring.pos().second], pts[offring.pos().first]);
//    return (std::abs(a) + std::abs(b)) / 2.;
//}

//template<class Sc>
//class Triangulator {
//    const std::vector<Vec<3, Sc>> *pts;
//    Ring *onring, *offring;
    
//    double calc_score() const
//    {
//        return trscore(*onring, *offring, *pts);
//    }
    
//    void synchronize_rings()
//    {
//        Ring lring = *offring;
//        auto minsc = trscore(*onring, lring, *pts);
//        size_t imin = lring.pos().first;
        
//        lring.inc();
        
//        while(!lring.is_finished()) {
//            double score = trscore(*onring, lring, *pts);
//            if (score < minsc) { minsc = score; imin = lring.pos().first; }
//            lring.inc();
//        }
        
//        offring->init(imin);
//    }
    
//    void emplace_indices(std::vector<Vec3i32> &indices)
//    {
//        Vec3i32 tr{int(onring->pos().first), int(onring->pos().second),
//                 int(offring->pos().first)};
//        if (onring->is_lower()) std::swap(tr(0), tr(1));
//        indices.emplace_back(tr);
//    }
    
//public:
//    void run(std::vector<Vec3i32> &indices)
//    {
//        synchronize_rings();
        
//        double score = 0, prev_score = 0;
//        while (!onring->is_finished() || !offring->is_finished()) {
//            prev_score = score;
//            if (onring->is_finished() || (score = calc_score()) > prev_score) {
//                std::swap(onring, offring);
//            } else {
//                emplace_indices(indices);
//                onring->inc();
//            }
//        }
//    }

//    explicit Triangulator(const std::vector<Vec<3, Sc>> *points,
//                          Ring &                    lower,
//                          Ring &                    upper)
//        : pts{points}, onring{&upper}, offring{&lower}
//    {}
//};

//template<class Sc, class I>
//void triangulate_wall(std::vector<Vec<3, Sc>> &pts,
//                      std::vector<Vec<3, I>> & ind,
//                      const Polygon &          lower,
//                      const Polygon &          upper,
//                      double                   lower_z_mm,
//                      double                   upper_z_mm)
//{
//    if (upper.points.size() < 3 || lower.points.size() < 3) return;

//    pts.reserve(lower.points.size() + upper.points.size());
//    for (auto &p : lower.points)
//        pts.emplace_back(unscaled(p.x()), unscaled(p.y()), lower_z_mm);
//    for (auto &p : upper.points)
//        pts.emplace_back(unscaled(p.x()), unscaled(p.y()), upper_z_mm);

//    ind.reserve(2 * (lower.size() + upper.size()));

//    Ring lring{0, lower.points.size()}, uring{lower.points.size(), pts.size()};
//    Triangulator t{&pts, lring, uring};
//    t.run(ind);
//}

//Wall triangulate_wall(const Polygon &lower,
//                      const Polygon &upper,
//                      double         lower_z_mm,
//                      double         upper_z_mm)
//{
//    if (upper.points.size() < 3 || lower.points.size() < 3) return {};
    
//    Wall wall;
//    auto &pts = wall.first;
//    auto &ind = wall.second;

//    pts.reserve(lower.points.size() + upper.points.size());
//    for (auto &p : lower.points)
//        wall.first.emplace_back(unscaled(p.x()), unscaled(p.y()), lower_z_mm);
//    for (auto &p : upper.points)
//        wall.first.emplace_back(unscaled(p.x()), unscaled(p.y()), upper_z_mm);
    
//    ind.reserve(2 * (lower.size() + upper.size()));
    
//    Ring lring{0, lower.points.size()}, uring{lower.points.size(), pts.size()};
//    Triangulator t{&pts, lring, uring};
//    t.run(ind);
    
//    return wall;
//}

} // namespace Slic3r