#include <Rcpp.h>
// Copyright (c) 2005,2006,2007,2009,2010,2011 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/Arrangement_on_surface_2/include/CGAL/Arr_point_location/Arr_trapezoid_ric_pl_impl.h $
// $Id: include/CGAL/Arr_point_location/Arr_trapezoid_ric_pl_impl.h b26b07a1242 $
// SPDX-License-Identifier: GPL-3.0-or-later OR LicenseRef-Commercial
//
//
// Author(s)     : Idit Haran   <haranidi@post.tau.ac.il>

#ifndef CGAL_ARR_TRAPEZOID_RIC_POINT_LOCATION_FUNCTIONS_H
#define CGAL_ARR_TRAPEZOID_RIC_POINT_LOCATION_FUNCTIONS_H

#include <CGAL/license/Arrangement_on_surface_2.h>


/*! \file
* Member-function definitions for the
* Arr_trapezoid_ric_point_location<Arrangement> class.
*/

#define CGAL_TRAP_DEBUG

#ifdef CGAL_TRG_DEBUG
        #define CGAL_TRAP_PRINT_DEBUG(expr)   Rcpp::Rcout << expr << std::endl
#else
        #define CGAL_TRAP_PRINT_DEBUG(expr)
#endif

namespace CGAL {

//-----------------------------------------------------------------------------
// Locate the arrangement feature containing the given point.
//
template <class Arrangement_2>
typename Arr_trapezoid_ric_point_location<Arrangement_2>::result_type
Arr_trapezoid_ric_point_location<Arrangement_2>::locate(const Point_2& p) const
{
  CGAL_TRAP_PRINT_DEBUG("locate point "<<p);

  //there are different internal compiler errors if we
  // typedef the Locate_type
  typename TD::Locate_type td_lt;

  Td_map_item& tr = td.locate(p,td_lt);

  CGAL_TRAP_PRINT_DEBUG("after td.locate");

  // treat special case, where trapezoid is unbounded.
  //        for then get_parent() is not defined
  if (td_lt==TD::UNBOUNDED_TRAPEZOID) {
    CGAL_TRAP_PRINT_DEBUG("UNBOUNDED_TRAPEZOID");

    Face_const_handle ubf =
      _get_unbounded_face(tr, p, All_sides_oblivious_category());

    //check isolated vertices
      Isolated_vertex_const_iterator   iso_verts_it;
      for (iso_verts_it = ubf->isolated_vertices_begin();
           iso_verts_it != ubf->isolated_vertices_end();
           ++iso_verts_it)
      {
      if (m_traits->equal_2_object()(p, iso_verts_it->point())) {
          Vertex_const_handle  vh = iso_verts_it;
        return make_result(vh);
        }
      }
    return make_result(ubf);
  }

  switch(td_lt)
  {
  case TD::POINT:
    {
      //p is interior so it should fall on Td_active_vertex
      Td_active_vertex& v (std::get<Td_active_vertex>(tr));
      CGAL_TRAP_PRINT_DEBUG("POINT");
      CGAL_assertion(!v.vertex()->is_at_open_boundary());
      return make_result(v.vertex());
    }
    break;

  case TD::CURVE:
    {
      Td_active_edge& e (std::get<Td_active_edge>(tr));
      Halfedge_const_handle h = e.halfedge();
      CGAL_TRAP_PRINT_DEBUG("CURVE");
      if ( m_traits->is_in_x_range_2_object()(h->curve(),p) &&
           m_traits->compare_y_at_x_2_object()(p,h->curve()) == EQUAL)
        return make_result(h);
      else {
        //ixx
        Rcpp::Rcerr << "curve is: "<< h->curve() <<" point is: "<< p <<std::endl;
        CGAL_error();
      }
    }
    break;

  case TD::TRAPEZOID:
    {
      Td_active_trapezoid t (std::get<Td_active_trapezoid>(tr));
      Halfedge_const_handle h = t.top();
      CGAL_TRAP_PRINT_DEBUG("TRAPEZOID");
      bool is_p_above_h = (m_traits->is_in_x_range_2_object()(h->curve(),p))
                       && (m_traits->compare_y_at_x_2_object()
                                          (p, h->curve()) == LARGER) ;
      bool is_h_ltr = (h->direction() == ARR_LEFT_TO_RIGHT);
      if (is_p_above_h != is_h_ltr) //if not, take the twin halfedge
      {
        h = h->twin();
      }

      Face_const_handle fh = h->face();
      //check isolated vertices
      Isolated_vertex_const_iterator   iso_verts_it;
      for (iso_verts_it = fh->isolated_vertices_begin();
          iso_verts_it != fh->isolated_vertices_end(); ++iso_verts_it)
      {
        if (m_traits->equal_2_object()(p, iso_verts_it->point())) {
          Vertex_const_handle  vh = iso_verts_it;
          return make_result(vh);
        }
      }

      return make_result(fh);
    }
    break;
  default:
    CGAL_TRAP_PRINT_DEBUG("DEFAULT");
    CGAL_error();
    break;
  }

  CGAL_TRAP_PRINT_DEBUG("EMPTY");
  return default_result();
}


/*! gets the unbounded face that contains the point when the trapezoid is unbounded
   */
template <class Arrangement>
typename Arr_trapezoid_ric_point_location<Arrangement>::Face_const_handle
Arr_trapezoid_ric_point_location<Arrangement>::
_get_unbounded_face(const Td_map_item& /* item */, const Point_2& /* p */,
                    Arr_all_sides_oblivious_tag) const
{
  //there's only one unbounded face
  return this->arrangement()->unbounded_faces_begin();
}


/*! gets the unbounded face that contains the point when the trapezoid
 * is unbounded
 */
template <class Arrangement>
typename Arr_trapezoid_ric_point_location<Arrangement>::Face_const_handle
Arr_trapezoid_ric_point_location<Arrangement>::
_get_unbounded_face(const Td_map_item& item,const Point_2& p,
                    Arr_not_all_sides_oblivious_tag) const
{
  Td_active_trapezoid tr (std::get<Td_active_trapezoid>(item));
  // Halfedge_const_handle h = tr.top();
  if (!tr.is_on_top_boundary() || !tr.is_on_bottom_boundary()) {
    //if one of top or bottom edges is defined
    Halfedge_const_handle h =
      (!tr.is_on_top_boundary()) ? tr.top() : tr.bottom();
    bool is_p_above_h = (m_traits->is_in_x_range_2_object()(h->curve(),p)) &&
      (m_traits->compare_y_at_x_2_object()(p, h->curve()) == LARGER);
    bool is_h_ltr = (h->direction() == ARR_LEFT_TO_RIGHT);
    if (is_p_above_h != is_h_ltr) //if not, take the twin halfedge
      h = h->twin();
    return h->face();
  }
  else if (!tr.is_on_left_boundary()) {
    //if top & bottom edges are not defined but the left() curve end is defined

    //there are different internal compiler errors if we
    // typedef the Locate_type
    typename TD::Locate_type td_lt;

    //locate the degenerate trapezoid containing tr.left()
    Td_map_item& left_v_item = td.locate(tr.left(),td_lt);
    CGAL_assertion(td_lt == TD::POINT);
    Halfedge_const_handle he;
    if (std::get_if<Td_active_vertex>(&left_v_item) != nullptr) {
      Td_active_vertex v(std::get<Td_active_vertex>(left_v_item));
      he = v.cw_he();
    }
    else {
      Td_active_fictitious_vertex
        v(std::get<Td_active_fictitious_vertex>(left_v_item));
      he = v.cw_he();
    }
    //cw_he() holds the "smallest" curve clockwise starting from 12 o'clock

    CGAL_assertion_code(Halfedge_const_handle invalid_he);
    CGAL_assertion(he != invalid_he);

    //the Halfedge_handle source is left_ee.
    // this way the face on it's left is the desired one

    //MICHAL: maybe add a verification that the above occurs
    return he->face();
  }
  else if (!tr.is_on_right_boundary()) {
    //if top, bottom, left edges are not defined but the right() curve end
    // is defined

    //there are different internal compiler errors if we
    // typedef the Locate_type
    typename TD::Locate_type td_lt;

    //locate the degenerate trapezoid of tr.right().
    Td_map_item& right_v_item = td.locate(tr.right(),td_lt);
    CGAL_assertion(td_lt == TD::POINT);
    Halfedge_const_handle he;
    if (std::get_if<Td_active_vertex>(&right_v_item)!= nullptr) {
      Td_active_vertex v(std::get<Td_active_vertex>(right_v_item));
      he = v.cw_he();
    }
    else {
      Td_active_fictitious_vertex
        v(std::get<Td_active_fictitious_vertex>(right_v_item));
      he = v.cw_he();
    }
    //its cw_he() holds the "smallest" curve clockwise starting from
    // 12 o'clock

    CGAL_assertion_code(Halfedge_handle invalid_he);
    CGAL_assertion(he != invalid_he);

    //the Halfedge_handle source is right_ee.
    // this way the face on it's left is the desired one

    //MICHAL: maybe add a verification that the above occurs
    return he->face();
  }

  //else, on all boundaries (top, bottom, left, right - are not defined),
  //    this is the only trapezoid in the map
  return this->arrangement()->unbounded_faces_begin();
}


//-----------------------------------------------------------------------------
// Locate the arrangement feature which a vertical ray emanating from the
// given point hits, considering isolated vertices.
//
template <class Arrangement>
typename Arr_trapezoid_ric_point_location<Arrangement>::result_type
Arr_trapezoid_ric_point_location<Arrangement>::
_vertical_ray_shoot(const Point_2& p, bool shoot_up) const
{
  //trying to workaround internal compiler error
  typename TD::Locate_type td_lt;
  Halfedge_const_handle invalid_he;

  Td_map_item& item = td.vertical_ray_shoot(p, td_lt, shoot_up);

  // treat special case, where trapezoid is unbounded.
  if (td_lt==TD::UNBOUNDED_TRAPEZOID)
  {
    return (_check_isolated_for_vertical_ray_shoot(invalid_he, p, shoot_up, item));
  }

  switch(td_lt)
  {
  case TD::POINT:
    {
      //p fell on Td_active_vertex
      Td_active_vertex& v (std::get<Td_active_vertex>(item));
      return (make_result(v.vertex()));
    }
    break;
 case TD::CURVE:
    {
      Td_active_edge& e (std::get<Td_active_edge>(item));
      Halfedge_const_handle h = e.halfedge();

      if ((shoot_up && h->direction() == ARR_LEFT_TO_RIGHT) ||
        (!shoot_up && h->direction() == ARR_RIGHT_TO_LEFT))
      {
        h=h->twin();
      }
      return make_result(h);
    }
    break;
  case TD::TRAPEZOID:
    {
      Td_active_trapezoid trpz (std::get<Td_active_trapezoid>(item));
      Halfedge_const_handle h = (shoot_up) ? trpz.top() : trpz.bottom();

      bool is_p_above_h = (m_traits->is_in_x_range_2_object()(h->curve(),p))
                       && (m_traits->compare_y_at_x_2_object()
                                          (p, h->curve()) == LARGER) ;
      bool is_h_ltr = (h->direction() == ARR_LEFT_TO_RIGHT);
      if (is_p_above_h != is_h_ltr) //if not, take the twin halfedge
        h = h->twin();
      return (_check_isolated_for_vertical_ray_shoot(h, p, shoot_up, item));
    }
    break;
  default:
    {
    CGAL_error();
    }
    break;
  }

  return (_check_isolated_for_vertical_ray_shoot(invalid_he, p, shoot_up, item));
}

//-----------------------------------------------------------------------------
// In vertical ray shoot, when the closest halfedge is found (or unbounded
// face) we check the isolated vertices inside the face to check whether there
// is an isolated vertex right above/below the query point.
//
template <typename Arrangement>
typename Arr_trapezoid_ric_point_location<Arrangement>::result_type
Arr_trapezoid_ric_point_location<Arrangement>::
_check_isolated_for_vertical_ray_shoot (Halfedge_const_handle halfedge_found,
                                        const Point_2& p,
                                        bool shoot_up,
                                        const Td_map_item& tr) const
{
  const auto* gt = this->arrangement()->geometry_traits();
  const Comparison_result point_above_under = (shoot_up ? SMALLER : LARGER);
  auto compare_x = gt->compare_x_2_object();
  auto compare_xy = gt->compare_xy_2_object();
  auto compare_y_at_x = gt->compare_y_at_x_2_object();

  Vertex_const_handle closest_iso_v;
  const Vertex_const_handle invalid_v;
  const Halfedge_const_handle invalid_he;

  // If the closest feature is a valid halfedge, take its incident face.
  // Otherwise, take the unbounded face.
  Face_const_handle face = (halfedge_found == invalid_he) ?
    _get_unbounded_face(tr, p, All_sides_oblivious_category()) :
    halfedge_found->face();

  // Go over the isolated vertices in the face.
  // The following statement pacifies MSVC. Without it the implicit conversion
  // from the iterator to the corresponding handle fails!
  Isolated_vertex_const_iterator iso_verts_it;
  for (iso_verts_it = face->isolated_vertices_begin();
       iso_verts_it != face->isolated_vertices_end(); ++iso_verts_it)
  {
    // The current isolated vertex should have the same x-coordinate as the
    // query point in order to be below or above it.
    if (compare_x (p, iso_verts_it->point()) != EQUAL) continue;

    // Make sure the isolated vertex is above the query point (if we shoot up)
    // or below it (if we shoot down).
    if (compare_xy (p, iso_verts_it->point()) != point_above_under) continue;

    // Check if the current isolated vertex lies closer to the query point than
    // the closest feature so far.
    if (closest_iso_v == invalid_v) {
      // Compare the current isolated vertex with the closest halfedge.
      if (halfedge_found == invalid_he ||
          compare_y_at_x (iso_verts_it->point(),
                          halfedge_found->curve()) == point_above_under)
      {
        closest_iso_v = iso_verts_it;
      }
    }
    else if (compare_xy (iso_verts_it->point(),
                         closest_iso_v->point()) == point_above_under)
    {
      closest_iso_v = iso_verts_it;
    }
  }

  // If we found an isolated vertex above (or under) the query point, return
  // a handle to this vertex.
  if (closest_iso_v != invalid_v) return make_result(closest_iso_v);

  // If we are inside the unbounded face, return this face.
  if (halfedge_found == invalid_he) return make_result(face);

  // Return the halfedge lying above (or below) the query point.
  return make_result(halfedge_found);
}

} //namespace CGAL

#endif

