// Copyright (c) 2006 Foundation for Research and Technology-Hellas (Greece).
// All rights reserved.
//
// This file is part of CGAL (www.cgal.org).
//
// $URL: https://github.com/CGAL/cgal/blob/v6.0.2/Voronoi_diagram_2/include/CGAL/Voronoi_diagram_2/Cached_degeneracy_testers.h $
// $Id: include/CGAL/Voronoi_diagram_2/Cached_degeneracy_testers.h e13ef800cb7 $
// SPDX-License-Identifier: GPL-3.0-or-later OR LicenseRef-Commercial
//
//
// Author(s)     : Menelaos Karavelas <mkaravel@iacm.forth.gr>

#ifndef CGAL_VORONOI_DIAGRAM_2_CACHED_DEGENERACY_TESTERS_H
#define CGAL_VORONOI_DIAGRAM_2_CACHED_DEGENERACY_TESTERS_H 1

#include <CGAL/license/Voronoi_diagram_2.h>


#include <CGAL/Voronoi_diagram_2/basic.h>

#include <CGAL/Voronoi_diagram_2/Edge_less.h>
#include <map>

#include <CGAL/Unique_hash_map.h>
#include <CGAL/TDS_2/internal/Edge_hash_function.h>


namespace CGAL {

namespace VoronoiDiagram_2 { namespace Internal {

//=========================================================================
//=========================================================================

template<class Edge_rejector_t, class Use_std_map = Tag_false>
class Cached_edge_rejector;

template<class Face_rejector_t, class Use_std_map = Tag_false>
class Cached_face_rejector;

//=========================================================================
//=========================================================================

template<class Edge_rejector_t>
class Cached_edge_rejector<Edge_rejector_t,Tag_true>
{
private:
  typedef Cached_edge_rejector<Edge_rejector_t,Tag_true>  Self;

public:
  typedef Edge_rejector_t                                Edge_rejector;
  typedef typename Edge_rejector::Delaunay_graph         Delaunay_graph;
  typedef typename Edge_rejector::Edge                   Edge;
  typedef typename Edge_rejector::Face_handle            Face_handle;
  typedef typename Edge_rejector::Edge_circulator        Edge_circulator;
  typedef typename Edge_rejector::All_edges_iterator     All_edges_iterator;
  typedef typename Edge_rejector::Finite_edges_iterator  Finite_edges_iterator;
  typedef typename Edge_rejector::result_type            result_type;

private:
  typedef std::map<Edge,bool,Edge_less<Edge> >   Edge_map;

  Edge opposite(const Delaunay_graph& dual, const Edge& e) const {
    int i_mirror = dual.tds().mirror_index(e.first, e.second);
    return Edge( e.first->neighbor(e.second), i_mirror );
  }

public:
  Cached_edge_rejector() {}
  Cached_edge_rejector(const Self& other) {
    e_rejector = other.e_rejector;
  }

  Self& operator=(const Self& other) {
    clear();
    e_rejector = other.e_rejector;
    return *this;
  }

  bool operator()(const Delaunay_graph& dual, const Edge& e) const {
    if ( dual.dimension() < 2 ) { return false; }

    typename Edge_map::iterator it = emap.find(e);
    if ( it != emap.end() ) { return it->second; }

    bool b = e_rejector(dual, e);

    Edge e_opp = opposite(dual, e);
    std::pair<Edge,bool> p = std::make_pair(e,b);
    emap.insert(p);
    p.first = e_opp;
    emap.insert(p);

    return b;
  }

  bool operator()(const Delaunay_graph& dual,
                  const Face_handle& f,        int i) const {
    return operator()(dual, Edge(f,i));
  }

  template <typename EdgeIterator>
  bool operator()(const Delaunay_graph& dual,
                  const EdgeIterator eit) const {
    return operator()(dual, *eit);
  }

  bool erase(const Edge& e) const {
    typename Edge_map::iterator it = emap.find(e);
    if ( it == emap.end() ) { return false; }

    // erase the edge from the map
    emap.erase(it);
    return true;
  }

  void clear() {
    emap.clear();
  }

  void swap(Self& /* other */) {
    // doing a real swap is not ready yet
#if 1
    clear();
#else
    e_rejector.swap(other.e_rejector);
    std::swap(emap, other.emap);
#endif
  }

  bool is_valid() const { return true; }

  bool is_valid(const Delaunay_graph& dual) const {
    bool valid = true;
    typename Edge_map::iterator it;
    for (it = emap.begin(); it != emap.end(); ++it) {
      valid = valid && dual.tds().is_edge(it->first.first,
                                          it->first.second);
    }
    return valid;
  }

private:
  Edge_rejector e_rejector;
  mutable Edge_map emap;
};

//=========================================================================

template<class Edge_rejector_t>
class Cached_edge_rejector<Edge_rejector_t,Tag_false>
{
private:
  typedef Cached_edge_rejector<Edge_rejector_t,Tag_false>  Self;

public:
  typedef Edge_rejector_t                                Edge_rejector;
  typedef typename Edge_rejector::Delaunay_graph         Delaunay_graph;
  typedef typename Edge_rejector::Edge                   Edge;
  typedef typename Edge_rejector::Face_handle            Face_handle;
  typedef typename Edge_rejector::Edge_circulator        Edge_circulator;
  typedef typename Edge_rejector::All_edges_iterator     All_edges_iterator;
  typedef typename Edge_rejector::Finite_edges_iterator  Finite_edges_iterator;
  typedef typename Edge_rejector::result_type            result_type;

private:
  enum Three_valued { UNDEFINED = -1, False, True };

  typedef Unique_hash_map<Edge,Three_valued,Edge_hash_function>
  Edge_map;

  Edge opposite(const Delaunay_graph& dual, const Edge& e) const {
    int i_mirror = dual.tds().mirror_index(e.first, e.second);
    return Edge( e.first->neighbor(e.second), i_mirror );
  }

public:
  Cached_edge_rejector() {}
  Cached_edge_rejector(const Self& other) {
    e_rejector = other.e_rejector;
  }

  Self& operator=(const Self& other) {
    clear();
    e_rejector = other.e_rejector;
    return *this;
  }

  bool operator()(const Delaunay_graph& dual, const Edge& e) const {
    if ( dual.dimension() < 2 ) { return false; }
    if ( emap.is_defined(e) && emap[e] != UNDEFINED ) {
      return (emap[e] == True);
    }

    bool b = e_rejector(dual, e);
    Three_valued b3 = (b ? True : False);
    emap[e] = b3;
    emap[opposite(dual, e)] = b3;

    return b;
  }

  bool operator()(const Delaunay_graph& dual,
                  const Face_handle& f,        int i) const {
    return operator()(dual, Edge(f,i));
  }

  template <typename EdgeIterator>
  bool operator()(const Delaunay_graph& dual,
                  const EdgeIterator eit) const {
    return operator()(dual, *eit);
  }

  bool erase(const Edge& e) const {
    if ( emap.is_defined(e) ) { emap[e] = UNDEFINED; }
    return true;
  }

  void clear() {
    emap.clear(UNDEFINED);
  }

  void swap(Self& /* other */) {
    // doing a real swap is not ready yet
#if 1
    clear();
#else
    e_rejector.swap(other.e_rejector);
    std::swap(emap, other.emap);
#endif
  }

  bool is_valid() const { return true; }

  bool is_valid(const Delaunay_graph& dual) const
  {
    bool valid = true;
    for (auto eit = dual.all_edges_begin(); eit != dual.all_edges_end(); ++eit) {
      const Edge& e = *eit;
      bool b = !emap.is_defined(e) || (emap[e] != UNDEFINED);
      valid = valid && b;
    }
    return valid;
  }

private:
  Edge_rejector e_rejector;
  mutable Edge_map emap;
};


//=========================================================================
//=========================================================================


template<class Face_rejector_t>
class Cached_face_rejector<Face_rejector_t,Tag_true>
{
  // tests whether a face has zero area
public:
  typedef Face_rejector_t                         Face_rejector;
  typedef typename Face_rejector::Delaunay_graph  Delaunay_graph;
  typedef typename Face_rejector::Vertex_handle   Vertex_handle;
  typedef typename Face_rejector::result_type     result_type;

private:
  typedef Cached_face_rejector<Face_rejector,Tag_true>  Self;

  typedef std::map<Vertex_handle,bool>  Vertex_map;

public:
  Cached_face_rejector() {}
  Cached_face_rejector(const Self& other) {
    f_rejector = other.f_rejector;
  }

  Self& operator=(const Self& other) {
    clear();
    f_rejector = other.f_rejector;
    return *this;
  }

  bool operator()(const Delaunay_graph& dual, const Vertex_handle& v) const {
    if ( dual.dimension() < 2 ) { return false; }

    typename Vertex_map::iterator it = vmap.find(v);
    if ( it != vmap.end() ) { return it->second; }

    bool b = f_rejector(dual, v);
    vmap.insert( std::make_pair(v,b) );
    return b;
  }

  bool erase(const Vertex_handle& v) const {
    typename Vertex_map::iterator it = vmap.find(v);
    if ( it == vmap.end() ) { return false; }

    // erase the edge from the map
    vmap.erase(it);
    return true;
  }


  void clear() {
    vmap.clear();
  }

  void swap(Self& /* other */) {
    // doing a real swap is not ready yet
#if 1
    clear();
#else
    f_rejector.swap(other.f_rejector);
    std::swap(vmap, other.vmap);
#endif
  }

  bool is_valid() const { return true; }

  bool is_valid(const Delaunay_graph& dual) const {
    bool valid = true;
    typename Vertex_map::iterator it;
    for (it = vmap.begin(); it != vmap.end(); ++it) {
      valid = valid && dual.tds().is_vertex(it->first);
    }
    return valid;
  }

private:
  Face_rejector f_rejector;
  mutable Vertex_map vmap;
};

//=========================================================================

template<class Face_rejector_t>
class Cached_face_rejector<Face_rejector_t,Tag_false>
{
  // tests whether a face has zero area
public:
  typedef Face_rejector_t                         Face_rejector;
  typedef typename Face_rejector::Delaunay_graph  Delaunay_graph;
  typedef typename Face_rejector::Vertex_handle   Vertex_handle;
  typedef typename Face_rejector::result_type     result_type;

private:
  typedef Cached_face_rejector<Face_rejector,Tag_false> Self;

  enum Three_valued { UNDEFINED = -1, False, True };
  typedef Unique_hash_map<Vertex_handle,Three_valued>   Vertex_map;

public:
  Cached_face_rejector() {}
  Cached_face_rejector(const Self& other) {
    f_rejector = other.f_rejector;
  }

  Self& operator=(const Self& other) {
    clear();
    f_rejector = other.f_rejector;
    return *this;
  }

  bool operator()(const Delaunay_graph& dual, const Vertex_handle& v) const {
    if ( dual.dimension() < 2 ) { return false; }
    if ( vmap.is_defined(v) && vmap[v] != UNDEFINED ) { return (vmap[v] == True); }

    bool b = f_rejector(dual, v);
    Three_valued b3 = (b ? True : False);
    vmap[v] = b3;
    return b;
  }

  bool erase(const Vertex_handle& v) const {
    if ( vmap.is_defined(v) ) { vmap[v] = UNDEFINED; }
    return true;
  }


  void clear() {
    vmap.clear(UNDEFINED);
  }

  void swap(Self& /* other */) {
    // doing a real swap is not ready yet
#if 1
    clear();
#else
    f_rejector.swap(other.f_rejector);
    std::swap(vmap, other.vmap);
#endif
  }

  bool is_valid() const { return true; }

  bool is_valid(const Delaunay_graph& dual) const {
    bool valid = true;
    typename Delaunay_graph::All_vertices_iterator vit;
    for (vit = dual.all_vertices_begin();
         vit != dual.all_vertices_end(); ++vit) {
      bool b = !vmap.is_defined(vit) || (vmap[vit] != UNDEFINED);
      valid = valid && b;
    }
    return valid;
  }

private:
  Face_rejector f_rejector;
  mutable Vertex_map vmap;
};

//=========================================================================
//=========================================================================

// Specialization for the identity face degeneracy tester

template<class DG> struct Identity_face_rejector;

template<class DG>
class Cached_face_rejector<Identity_face_rejector<DG>,Tag_false>
  : public Identity_face_rejector<DG>
{
 private:
  typedef Identity_face_rejector<DG>            Base;
  typedef Cached_face_rejector<Base,Tag_false>  Self;

 public:
  bool erase(const typename Base::Vertex_handle&) const { return true; }

  bool is_valid() const { return true; }

  bool is_valid(const typename Base::Delaunay_graph&) const { return true; }
};

template<class DG>
class Cached_face_rejector<Identity_face_rejector<DG>,Tag_true>
  : public Cached_face_rejector<Identity_face_rejector<DG>,Tag_false>
{};

//=========================================================================
//=========================================================================

} } //namespace VoronoiDiagram_2::Internal

} //namespace CGAL

#endif // CGAL_VORONOI_DIAGRAM_2_CACHED_DEGENERACY_TESTERS_H
