// Copyright (c) 2005,2006,2007,2008,2009,2010,2011 Tel-Aviv University (Israel).
// All rights reserved.
//
// This file is part of CGAL (www.cgal.org).
//
// $URL: https://github.com/CGAL/cgal/blob/v6.1.1/Arrangement_on_surface_2/include/CGAL/Arr_point_location/Arr_lm_middle_edges_generator.h $
// $Id: include/CGAL/Arr_point_location/Arr_lm_middle_edges_generator.h 08b27d3db14 $
// SPDX-License-Identifier: GPL-3.0-or-later OR LicenseRef-Commercial
//
//
// Author(s)     : Idit Haran   <haranidi@post.tau.ac.il>

#ifndef CGAL_ARR_LANDMARKS_MIDDLE_EDGES_GENERATOR_H
#define CGAL_ARR_LANDMARKS_MIDDLE_EDGES_GENERATOR_H

#include <CGAL/license/Arrangement_on_surface_2.h>


/*! \file
* Definition of the Arr_middle_edges_landmarks_generator<Arrangement> template.
*/

#include <CGAL/Arr_point_location/Arr_lm_generator_base.h>

namespace CGAL {

/*! \class
* This class is related to the Landmarks point location, and given as
* a parameter (or template parameter) to it.
* It inherites from Arr_lm_generator and  implements the
* function called "void _create_point_list(Point_list &)"
* to creates the set of landmarks, which are the middle points of the
* arrangement edges, which must be segments !
* IMPORTANT: THIS ALGORITHM WORKS ONLY FOR SEGMENTS !!!
*/
template <typename Arrangement_,
          typename Nearest_neighbor_ =
            Arr_landmarks_nearest_neighbor<Arrangement_> >
class Arr_middle_edges_landmarks_generator :
    public Arr_landmarks_generator_base<Arrangement_, Nearest_neighbor_>
{
public:
  typedef Arrangement_                                        Arrangement_2;
  typedef Nearest_neighbor_                             Nearest_neighbor;

private:
  typedef Arr_middle_edges_landmarks_generator<Arrangement_2, Nearest_neighbor>
                                                        Self;
  typedef Arr_landmarks_generator_base<Arrangement_2, Nearest_neighbor>
                                                        Base;

public:
  typedef typename Arrangement_2::Geometry_traits_2     Geometry_traits_2;
  typedef typename Arrangement_2::Edge_const_iterator        Edge_const_iterator;
  typedef typename Arrangement_2::Vertex_const_handle   Vertex_const_handle;
  typedef typename Arrangement_2::Halfedge_const_handle Halfedge_const_handle;
  typedef typename Arrangement_2::Face_const_handle     Face_const_handle;
  typedef typename Arrangement_2::Vertex_handle                Vertex_handle;
  typedef typename Arrangement_2::Halfedge_handle        Halfedge_handle;
  typedef typename Arrangement_2::Face_handle                Face_handle;
  typedef typename Arrangement_2::Vertex_const_iterator Vertex_const_iterator;
  typedef typename Arrangement_2::Ccb_halfedge_circulator
                                                        Ccb_halfedge_circulator;
  typedef typename Base::NN_Points_set                  NN_Points_set;
  typedef typename Base::NN_Point_2                     NN_Point_2;

  typedef typename Geometry_traits_2::Point_2                Point_2;
  typedef std::vector<Point_2>                                Points_set;

  typedef typename Base::PL_result_type                 PL_result_type;

private:
  /*! Copy constructor - not supported. */
  Arr_middle_edges_landmarks_generator(const Self&);

  /*! Assignment operator - not supported. */
  Self& operator=(const Self&);

public:
  /*! Constructor from an arrangement.
   * \param arr(in) The arrangement.
   * \param lm_num(in)
   */
  Arr_middle_edges_landmarks_generator(const Arrangement_2& arr,
                                       int /* lm_num */ = -1) :
    Base(arr)
  {
    //CGAL_PRINT_DEBUG("Arr_middle_edges_landmarks_generator constructor.");
    this->build_landmark_set();
  }

  // Observer functions that should be empty, because they
  // got nothing to do with middle edges
  //-------------------------------------------------
  virtual void after_create_vertex(Vertex_handle /* v */) {}
  virtual void after_split_face(Face_handle /* f */,
                                Face_handle /* new_f */, bool /* is_hole */)
  {}
  virtual void after_add_hole(Ccb_halfedge_circulator /* h */) {}

  virtual void after_merge_face(Face_handle /* f */) {}
  virtual void after_move_hole(Ccb_halfedge_circulator /* h */) {}
  virtual void after_remove_vertex() {}
  virtual void after_remove_hole(Face_handle /* f */) {}

protected:
  /*! Create a set of middle_edges points
   * the number of points is equal to the number of edges in the arrangement.
   */
  virtual void _create_nn_points_set(NN_Points_set& nn_points)
  {
    //CGAL_PRINT_DEBUG("create_middle_edges_points_list");
    Edge_const_iterator    eit;
    Halfedge_const_handle  hh;
    Arrangement_2* arr = this->arrangement();

    if (arr->number_of_vertices() == 1) {
      //special treatment for arrangement with one isolated verrtex
      Vertex_const_iterator vit = arr->vertices_begin();
      PL_result_type obj = this->pl_make_result(vit);
      Point_2 p(vit->point());
      NN_Point_2 np(p, obj);
      nn_points.push_back(np);

      return;
    }
    for (eit=arr->edges_begin(); eit != arr->edges_end(); ++eit) {
      //get 2 endpoints of edge
      hh = eit;
      const Point_2& p1 = hh->source()->point();
      const Point_2& p2 = hh->target()->point();
      Point_2 p((p1.x()+p2.x())/2, (p1.y()+p2.y())/2);

      //CGAL_PRINT_DEBUG("mid point is= " << p);

      PL_result_type obj = this->pl_make_result(hh);
      NN_Point_2 np(p, obj);
      nn_points.push_back(np);
    }
  }

  virtual void _create_points_set(Points_set& /* points */)
  {
    std::cerr << "should not reach here!" << std::endl;
    CGAL_error();
  }
};

} //namespace CGAL

#endif
