// Copyright (c) 2002,2011 Utrecht University (The Netherlands).
// All rights reserved.
//
// This file is part of CGAL (www.cgal.org).
//
// $URL: https://github.com/CGAL/cgal/blob/v6.0.1/Spatial_searching/include/CGAL/Euclidean_distance_sphere_point.h $
// $Id: include/CGAL/Euclidean_distance_sphere_point.h 50cfbde3b84 $
// SPDX-License-Identifier: GPL-3.0-or-later OR LicenseRef-Commercial
//
//
// Author(s)     : Hans Tangelder (<hanst@cs.uu.nl>)


#ifndef CGAL_EUCLIDEAN_DISTANCE_SPHERE_POINT_H
#define CGAL_EUCLIDEAN_DISTANCE_SPHERE_POINT_H

#include <CGAL/license/Spatial_searching.h>


#include <CGAL/Kd_tree_rectangle.h>
#include <CGAL/number_utils.h>
#include <CGAL/Spatial_searching/internal/Get_dimension_tag.h>
#include <vector>

namespace CGAL {

  template <class SearchTraits>
  class Euclidean_distance_sphere_point {


    SearchTraits traits;

    public:

    typedef typename SearchTraits::Point_d Point_d;
    typedef typename SearchTraits::Sphere_d Sphere_d;
    typedef typename SearchTraits::FT    FT;
    typedef typename SearchTraits::Construct_center_d Construct_center_d;
    typedef typename SearchTraits::Compute_squared_radius_d Compute_squared_radius_d;
    typedef typename SearchTraits::Construct_cartesian_const_iterator_d Construct_cartesian_const_iterator_d;
    typedef typename SearchTraits::Cartesian_const_iterator_d Cartesian_const_iterator_d;
    typedef Sphere_d Query_item;
    typedef typename internal::Get_dimension_tag<SearchTraits>::Dimension Dimension;
    public:

            // default constructor
            Euclidean_distance_sphere_point(const SearchTraits& traits_=SearchTraits()):traits(traits_) {}


        inline FT transformed_distance(const Sphere_d& q, const Point_d& p) const {
                Point_d c= Construct_center_d()(q);
                FT distance = FT(0);
                Construct_cartesian_const_iterator_d construct_it=traits.construct_cartesian_const_iterator_d_object();
                Cartesian_const_iterator_d cit = construct_it(c),
                  ce = construct_it(c,1), pit = construct_it(p);
                for(; cit != ce; cit++, pit++){
                  distance += ((*cit)-(*pit))*((*cit)-(*pit));
                }
                distance += - Compute_squared_radius_d()(q);
                if (distance<0) distance=FT(0);
                return distance;
        }


        inline FT min_distance_to_rectangle(const Sphere_d& q,
                                             const Kd_tree_rectangle<FT,Dimension>& r) const {
                Point_d c= Construct_center_d()(q);
                FT distance = FT(0);
                Construct_cartesian_const_iterator_d construct_it=traits.construct_cartesian_const_iterator_d_object();
                Cartesian_const_iterator_d cit = construct_it(c),
                  ce = construct_it(c,1);
                for (unsigned int i = 0; cit != ce; ++i, ++cit) {
                        if ((*cit) < r.min_coord(i))
                                distance +=
                                (r.min_coord(i)-(*cit))*(r.min_coord(i)-(*cit));
                        else if ((*cit) > r.max_coord(i))
                                distance +=
                                ((*cit)-r.max_coord(i))*((*cit)-r.max_coord(i));

                };
                distance += - Compute_squared_radius_d()(q);
                if (distance<0) distance=FT(0);
                return distance;
        }

        inline FT min_distance_to_rectangle(const Sphere_d& q,
                                             const Kd_tree_rectangle<FT,Dimension>& r,std::vector<FT>& dists) const {
                Point_d c= Construct_center_d()(q);
                FT distance = FT(0);
                Construct_cartesian_const_iterator_d construct_it=traits.construct_cartesian_const_iterator_d_object();
                Cartesian_const_iterator_d cit = construct_it(c),
                  ce = construct_it(c,1);
                for (unsigned int i = 0; cit != ce; ++i, ++cit) {
                        if ((*cit) < r.min_coord(i)){
                                dists[i] =(r.min_coord(i)-(*cit));
                                distance += dists[i] * dists[i];
                        }
                        else if ((*cit) > r.max_coord(i)){
                                dists[i] = ((*cit)-r.max_coord(i));
                                distance +=  dists[i] * dists[i];
                        }
                };
                distance += - Compute_squared_radius_d()(q);
                if (distance<0) distance=FT(0);
                return distance;
        }

        inline FT max_distance_to_rectangle(const Sphere_d& q,
                                              const Kd_tree_rectangle<FT,Dimension>& r) const {
          Construct_center_d construct_center_d;
                Point_d c = construct_center_d(q);
                FT distance=FT(0);
                Construct_cartesian_const_iterator_d construct_it=traits.construct_cartesian_const_iterator_d_object();
                Cartesian_const_iterator_d cit = construct_it(c),
                  ce = construct_it(c,1);
                for (unsigned int i = 0; cit != ce; ++i, ++cit) {
                                if ((*cit) <= (r.min_coord(i)+r.max_coord(i))/FT(2.0))
                                        distance += (r.max_coord(i)-(*cit))*(r.max_coord(i)-(*cit));
                                else
                                        distance += ((*cit)-r.min_coord(i))*((*cit)-r.min_coord(i));
                };
                distance += - Compute_squared_radius_d()(q);
                if (distance<0) distance=FT(0);
                return distance;
        }

        inline FT max_distance_to_rectangle(const Sphere_d& q,
                                              const Kd_tree_rectangle<FT,Dimension>& r,std::vector<FT>& dists) const {
          Construct_center_d construct_center_d;
                Point_d c = construct_center_d(q);
                FT distance=FT(0);
                Construct_cartesian_const_iterator_d construct_it=traits.construct_cartesian_const_iterator_d_object();
                Cartesian_const_iterator_d cit = construct_it(c),
                  ce = construct_it(c,1);
                for (unsigned int i = 0; cit != ce; ++i, ++cit) {
                                if ((*cit) <= (r.min_coord(i)+r.max_coord(i))/FT(2.0)){
                                        dists[i] = (r.max_coord(i)-(*cit));
                                        distance += dists[i] * dists[i];
                                }
                                else{
                                        dists[i] = ((*cit)-r.min_coord(i));
                                        distance += dists[i] * dists[i];
                                }
                };
                distance += - Compute_squared_radius_d()(q);
                if (distance<0) distance=FT(0);
                return distance;
        }



  inline FT transformed_distance(FT d) const {
                return d*d;
        }

  inline FT inverse_of_transformed_distance(FT d) const {
                return CGAL::sqrt(d);
        }

  }; // class Euclidean_distance_sphere_point

} // namespace CGAL
#endif // EUCLIDEAN_DISTANCE_SPHERE_POINT_H

