// 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/v5.6.2/Arrangement_on_surface_2/include/CGAL/Arr_point_location/Arr_lm_random_generator.h $
// $Id: Arr_lm_random_generator.h 014c06fd19a 2022-11-14T15:32:47+01:00 albert-github
// SPDX-License-Identifier: GPL-3.0-or-later OR LicenseRef-Commercial
//
// Author(s)     : Idit Haran   <haranidi@post.tau.ac.il>
//                 Ron Wein     <wein@post.tau.ac.il>

#ifndef CGAL_ARR_LANDMARKS_RANDOM_GENERATOR_H
#define CGAL_ARR_LANDMARKS_RANDOM_GENERATOR_H

#include <CGAL/license/Arrangement_on_surface_2.h>


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

#include <CGAL/Arr_point_location/Arr_lm_generator_base.h>
#include <CGAL/Random.h>

namespace CGAL {

/*! \class Arr_random_landmarks_generator
 * A generator for the landmarks point-locatoion class, which uses a
 * random set of points as its set of landmarks.
*/
template <typename Arrangement_,
          typename Nearest_neighbor_ =
            Arr_landmarks_nearest_neighbor<Arrangement_> >
class Arr_random_landmarks_generator :
    public Arr_landmarks_generator_base<Arrangement_, Nearest_neighbor_>
{
public:
  typedef Arrangement_                                  Arrangement_2;
  typedef Nearest_neighbor_                             Nearest_neighbor;

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

public:
  typedef typename Arrangement_2::Geometry_traits_2     Geometry_traits_2;
  typedef typename Arrangement_2::Point_2               Point_2;
  typedef typename Base::Points_set                     Points_set;
  typedef typename Arrangement_2::Vertex_const_iterator Vertex_const_iterator;

protected:
  // Data members:
  unsigned int num_landmarks;

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

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

public:
  /*! Constructor from an arrangement.
   * \param arr (in) The arrangement.
   */
  Arr_random_landmarks_generator(const Arrangement_2& arr,
                                 unsigned int n_landmarks = 0) :
    Base(arr),
    num_landmarks(n_landmarks)
  { this->build_landmark_set(); }

protected:
  /*! Create a set of random points (the number of points is given as a
   * parameter to the constructor, or is taken from the arrangement size).
   * The coordinates of the landmarks are selected randomly in the
   * bounding rectangle of the Arrangement's vertices
   */
  virtual void _create_points_set(Points_set& points)
  {
    points.clear();

    // Go over the arrangement vertices and construct their bounding box.
    const Arrangement_2* arr = this->arrangement();
    Vertex_const_iterator vit;
    double x_min = 0, x_max = 1, y_min = 0, y_max = 1;
    double x, y;
    bool first = true;

    for (vit=arr->vertices_begin(); vit != arr->vertices_end(); ++vit) {
      x = CGAL::to_double(vit->point().x());
      y = CGAL::to_double(vit->point().y());

      if (first) {
        x_min = x_max = x;
        y_min = y_max = y;
        first = false;
      }
      else {
        if (x < x_min) x_min = x;
        else if (x > x_max) x_max = x;

        if (y < y_min) y_min = y;
        else if (y > y_max) y_max = y;
      }
    }

    // Create N random landmarks. If N was not given to the constructor,
    // set it to be the number of vertices in the arrangement.
    if (num_landmarks == 0)
      num_landmarks = static_cast<unsigned int>(arr->number_of_vertices());

    CGAL::Random random;
    for (unsigned int i = 0; i < num_landmarks; ++i) {
      double px = (x_min == x_max) ? x_min : random.get_double(x_min, x_max);
      double py = (y_min == y_max) ? y_min : random.get_double(y_min, y_max);
      points.push_back(Point_2(px, py));
    }
  }
};

} //namespace CGAL


#endif
