// Copyright (c) 2023 GeometryFactory Sarl (France).
// All rights reserved.
//
// This file is part of CGAL (www.cgal.org).
//
// $URL$
// $Id$
// SPDX-License-Identifier: GPL-3.0-or-later OR LicenseRef-Commercial
//
//
// Author(s)     : Sven Oesau, Florent Lafarge, Dmitry Anisimov, Simon Giraudot

#ifndef CGAL_KSR_3_GRAPHCUT_H
#define CGAL_KSR_3_GRAPHCUT_H

// #include <CGAL/license/Kinetic_shape_reconstruction.h>

// CGAL includes.
#include <CGAL/assertions.h>
//#define CGAL_DO_NOT_USE_BOYKOV_KOLMOGOROV_MAXFLOW_SOFTWARE
#include <CGAL/boost/graph/alpha_expansion_graphcut.h>
#include <CGAL/boost/graph/Alpha_expansion_MaxFlow_tag.h>
#include <CGAL/Exact_predicates_inexact_constructions_kernel.h>
#include <CGAL/Delaunay_triangulation_2.h>
#include <CGAL/Delaunay_triangulation_3.h>
#include <CGAL/Cartesian_converter.h>

// Internal includes.
#include <CGAL/KSP/utils.h>
#include <CGAL/KSP/debug.h>
#include <CGAL/KSP_3/Data_structure.h>

namespace CGAL {
namespace KSR_3 {

#ifdef DOXYGEN_RUNNING
#else

  template<typename GeomTraits>
  class Graphcut {

  public:
    using Kernel = GeomTraits;

    using FT          = typename Kernel::FT;
    using Point_3    = typename Kernel::Point_3;
    using Triangle_2 = typename Kernel::Triangle_2;
    using Triangle_3 = typename Kernel::Triangle_3;
    using Indices    = std::vector<std::size_t>;

    using Delaunay_2 = CGAL::Delaunay_triangulation_2<Kernel>;
    using Delaunay_3 = CGAL::Delaunay_triangulation_3<Kernel>;

    Graphcut(
      const FT lambda) : m_lambda(lambda) { }

    void solve(const std::vector<std::pair<std::size_t, std::size_t> >& edges, const std::vector<FT>& edge_weights, const std::vector<std::vector<double> > &cost_matrix, std::vector<std::size_t> &labels) {
      assert(edges.size() == edge_weights.size());
      assert(!cost_matrix.empty());
      labels.resize(cost_matrix[0].size());
      for (std::size_t i = 0; i < cost_matrix[0].size(); i++) {
        // Verify quadratic size
        assert(cost_matrix[0].size() == cost_matrix[1].size());
        labels[i] = (cost_matrix[0][i] > cost_matrix[1][0]) ? 1 : 0;
      }
      compute_graphcut(edges, edge_weights, cost_matrix, labels);
    }

  private:
    const FT m_lambda;

    double get_face_cost(
      const FT face_prob, const FT face_weight) const {

      CGAL_assertion(face_prob   >= FT(0) && face_prob   <= FT(1));
      CGAL_assertion(face_weight >= FT(0) && face_weight <= FT(1));

      const double weight = CGAL::to_double(face_weight);
      const double value  = (1.0 - CGAL::to_double(face_prob));
      return weight * value;
    }

    void compute_graphcut(
      const std::vector< std::pair<std::size_t, std::size_t> >& edges,
      const std::vector<FT>& edge_costs,
      const std::vector< std::vector<double> >& cost_matrix,
      std::vector<std::size_t>& labels) const {
      std::vector<std::size_t> tmp = labels;

      std::cout << std::endl << "beta" << m_lambda << std::endl;

      std::vector<FT> edge_costs_lambda(edge_costs.size());
      std::vector<std::vector<double> > cost_matrix_lambda(2);

      for (std::size_t i = 0; i < edge_costs.size(); i++)
        edge_costs_lambda[i] = edge_costs[i] * m_lambda;

      for (std::size_t i = 0; i < cost_matrix.size(); i++) {
        cost_matrix_lambda[i].resize(cost_matrix[i].size());
        for (std::size_t j = 0; j < cost_matrix[i].size(); j++)
          cost_matrix_lambda[i][j] = cost_matrix[i][j] * (1.0 - m_lambda);
      }


      double min = 10000000000;
      double max = -min;
      double edge_sum = 0;
      for (std::size_t i = 0; i < edge_costs.size(); i++) {
        min = (std::min<double>)(edge_costs[i], min);
        max = (std::max<double>)(edge_costs[i], max);
        edge_sum += edge_costs[i] * m_lambda;
      }

      std::cout << "edge costs" << std::endl;
      std::cout << "sum: " << edge_sum << std::endl;
      std::cout << "min: " << min << std::endl;
      std::cout << "max: " << max << std::endl;

      min = 1000000000;
      max = -min;

      std::size_t sum_inside = 0;
      std::size_t sum_outside = 0;

      for (std::size_t i = 6; i < cost_matrix[0].size(); i++) {
        sum_inside += cost_matrix[0][i];
        sum_outside += cost_matrix[1][i];
        min = (std::min<double>)(cost_matrix[0][i], min);
        min = (std::min<double>)(cost_matrix[1][i], min);
        max = (std::max<double>)(cost_matrix[0][i], max);
        max = (std::max<double>)(cost_matrix[1][i], max);
      }

      std::cout << "label costs" << std::endl;
      std::cout << "min: " << min << std::endl;
      std::cout << "max: " << max << std::endl;
      std::cout << "sum inside: " << sum_inside << std::endl;
      std::cout << "sum outside: " << sum_outside << std::endl;

      CGAL::alpha_expansion_graphcut(edges, edge_costs_lambda, cost_matrix_lambda, labels);
      /*
      CGAL::min_cut(
            edges, edge_costs, cost_matrix, labels, CGAL::parameters::implementation_tag(CGAL::Alpha_expansion_MaxFlow_tag()));*/

/*
      bool difference = false;
      for (std::size_t i = 0; i < labels.size(); i++) {
        if (tmp[i] != labels[i]) {
          difference = true;
          break;
        }
      }

      std::cout << "Labels changed: " << difference << std::endl;*/
    }

/*
    void apply_new_labels(
      const std::vector<std::size_t>& labels,
      std::vector<Volume_cell>& volumes) const {

      CGAL_assertion((volumes.size() + 6) == labels.size());
      for (std::size_t i = 0; i < volumes.size(); ++i) {
        const std::size_t label = labels[i + 6];
        auto& volume = volumes[i];

        if (label == 0) {
          volume.visibility = Visibility_label::INSIDE;
        } else {
          volume.visibility = Visibility_label::OUTSIDE;
        }
      }
    }*/
  };

#endif //DOXYGEN_RUNNING

} // KSR_3
} // CGAL

#endif // CGAL_KSR_3_GRAPHCUT_H