#include <CGAL/Exact_predicates_inexact_constructions_kernel.h>
#include <CGAL/algorithm.h>
#include <cstdio>
#include <cstring>
#include <iostream>
#include <fstream>
#include <vector>
#include <list>

#include <CGAL/Alpha_shape_2.h>
#include <CGAL/Alpha_shape_face_base_2.h>
#include <CGAL/Alpha_shape_vertex_base_2.h>
#include <CGAL/Delaunay_triangulation_2.h>

typedef double coord_type;

typedef CGAL::Exact_predicates_inexact_constructions_kernel K;

typedef K::Point_2  Point;
typedef K::Segment_2  Segment;
typedef K::Line_2  Line;
typedef K::Triangle_2  Triangle;

//ExactAlphaComparisonTag is false
typedef K Gt;
typedef CGAL::Alpha_shape_vertex_base_2<Gt> Vb;
typedef CGAL::Alpha_shape_face_base_2<Gt>  Fb;
typedef CGAL::Triangulation_data_structure_2<Vb,Fb> Tds;
typedef CGAL::Delaunay_triangulation_2<Gt,Tds> Triangulation_2;
typedef CGAL::Alpha_shape_2<Triangulation_2>  Alpha_shape_2;

//ExactAlphaComparisonTag is true
typedef K Gt;
typedef CGAL::Alpha_shape_vertex_base_2<Gt,CGAL::Default,CGAL::Tag_true> Vb_TT;
typedef CGAL::Alpha_shape_face_base_2<Gt,CGAL::Default,CGAL::Tag_true>  Fb_TT;
typedef CGAL::Triangulation_data_structure_2<Vb_TT,Fb_TT> Tds_TT;
typedef CGAL::Delaunay_triangulation_2<Gt,Tds_TT> Triangulation_2_TT;
typedef CGAL::Alpha_shape_2<Triangulation_2_TT,CGAL::Tag_true>  Alpha_shape_2_TT;

typedef Alpha_shape_2::Face  Face;
typedef Alpha_shape_2::Vertex Vertex;
typedef Alpha_shape_2::Edge Edge;
typedef Alpha_shape_2::Face_handle  Face_handle;
typedef Alpha_shape_2::Vertex_handle Vertex_handle;

typedef Alpha_shape_2::Face_circulator  Face_circulator;
typedef Alpha_shape_2::Vertex_circulator  Vertex_circulator;

typedef Alpha_shape_2::Locate_type Locate_type;

typedef Alpha_shape_2::Face_iterator  Face_iterator;
typedef Alpha_shape_2::Vertex_iterator  Vertex_iterator;
typedef Alpha_shape_2::Edge_iterator  Edge_iterator;
typedef Alpha_shape_2::Edge_circulator  Edge_circulator;

typedef Alpha_shape_2::Alpha_iterator Alpha_iterator;

//---------------------------------------------------------------------

template <class Alpha_shape,class InputIterator, class OutputIterator>
void
alpha_edges(InputIterator begin, InputIterator end,
	    const typename Alpha_shape::FT &Alpha,
	    bool mode,
	    OutputIterator out)
{ 
  typedef typename Alpha_shape::Alpha_shape_edges_iterator Alpha_shape_edges_iterator;
  typename Alpha_shape::Triangulation dt;
  dt.insert(begin,end);
  Alpha_shape A(dt);
  
  if (mode) 
    { A.set_mode(Alpha_shape::GENERAL); } 
  else 
    { A.set_mode(Alpha_shape::REGULARIZED); };
  A.set_alpha(Alpha);

  for(Alpha_shape_edges_iterator it =  A.alpha_shape_edges_begin();
      it != A.alpha_shape_edges_end();
      ++it){
    *out++ = A.segment(*it);
  }
}
//---------------------------------------------------------------------

template <class OutputIterator>
bool
file_input(OutputIterator out)
{
  std::ifstream is("./data/fin", std::ios::in);

  if(is.fail()){
    std::cerr << "unable to open file for input" << std::endl;
    return false;
  }

  int n;
  is >> n;
  std::cout << "Reading " << n << " points from file" << std::endl;
  CGAL::cpp11::copy_n(std::istream_iterator<Point>(is), n, out);

  return true;
}
    
//------------------ main -------------------------------------------

int main()
{
  std::list<Point> points;
  if(! file_input(std::back_inserter(points))){
    return -1;
  }
  
  //ExactAlphaComparisonTag is False
  {
    std::vector<Segment> segments;
    alpha_edges<Alpha_shape_2>(points.begin(), points.end(),
          10000.,Alpha_shape_2::GENERAL, 
          std::back_inserter(segments));

    std::cout << segments.size() << " alpha shape edges" << std::endl;
    std::cout << "Alpha Shape computed" << std::endl;
  }

  //ExactAlphaComparisonTag is True
  {
    std::vector<Segment> segments;
    alpha_edges<Alpha_shape_2_TT>(points.begin(), points.end(),
          10000.,Alpha_shape_2_TT::GENERAL, 
          std::back_inserter(segments));

    std::cout << segments.size() << " alpha shape edges" << std::endl;
    std::cout << "Alpha Shape computed" << std::endl;
  }
  
  
  return 0;
}
