#include <CGAL/Installation/internal/disable_deprecation_warnings_and_errors.h>
#include <CGAL/Exact_predicates_exact_constructions_kernel.h>
#include <CGAL/Barycentric_coordinates_2/triangle_coordinates_2.h>
#include <CGAL/Barycentric_coordinates_2/Discrete_harmonic_2.h>
#include <CGAL/Barycentric_coordinates_2/Generalized_barycentric_coordinates_2.h>
#include <CGAL/Barycentric_coordinates_2/Discrete_harmonic_coordinates_2.h>

typedef CGAL::Exact_predicates_exact_constructions_kernel Kernel;

typedef Kernel::FT      Scalar;
typedef Kernel::Point_2 Point;

typedef std::vector<Scalar> Coordinate_vector;
typedef std::vector<Point>  Point_vector;

typedef std::back_insert_iterator<Coordinate_vector> Vector_insert_iterator;

typedef CGAL::Barycentric_coordinates::Triangle_coordinates_2<Kernel> Triangle_coordinates;
typedef CGAL::Barycentric_coordinates::Discrete_harmonic_2<Kernel> Discrete_harmonic;
typedef CGAL::Barycentric_coordinates::Generalized_barycentric_coordinates_2<Discrete_harmonic, Kernel> Discrete_harmonic_coordinates;

typedef std::optional<Vector_insert_iterator> Output_type;

using std::cout; using std::endl; using std::string;

int main()
{
  const Point first_vertex  = Point(0, 0);
  const Point second_vertex = Point(1, 0);
  const Point third_vertex  = Point(0, 1);

  Triangle_coordinates triangle_coordinates(first_vertex, second_vertex, third_vertex);

  Point_vector vertices(3);
  vertices[0] = first_vertex; vertices[1] = second_vertex; vertices[2] = third_vertex;

  Discrete_harmonic_coordinates discrete_harmonic_coordinates(vertices.begin(), vertices.end());

  Coordinate_vector tri_coordinates;
  Coordinate_vector old_coordinates;
  Coordinate_vector new_coordinates;

  const Scalar step  = Scalar(1) / Scalar(100);
  const Scalar scale = Scalar(50);

  int count = 0;
  const Scalar limit = scale * step;

  for (Scalar x = step; x < limit; x += step) {
    for (Scalar y = step; y < limit; y += step) {
      const Point point(x, y);

      /* const Output_type tri_result =  */triangle_coordinates(point, tri_coordinates);
      /* const Output_type  dh_result =  */discrete_harmonic_coordinates(point, old_coordinates);
      CGAL::Barycentric_coordinates::discrete_harmonic_coordinates_2(
        vertices, point, std::back_inserter(new_coordinates));

      assert(
        tri_coordinates[count + 0] - old_coordinates[count + 0] == Scalar(0) &&
        tri_coordinates[count + 1] - old_coordinates[count + 1] == Scalar(0) &&
        tri_coordinates[count + 2] - old_coordinates[count + 2] == Scalar(0) );

      assert(
        old_coordinates[count + 0] - new_coordinates[count + 0] == Scalar(0) &&
        old_coordinates[count + 1] - new_coordinates[count + 1] == Scalar(0) &&
        old_coordinates[count + 2] - new_coordinates[count + 2] == Scalar(0) );

      if (
        tri_coordinates[count + 0] - old_coordinates[count + 0] != Scalar(0) ||
        tri_coordinates[count + 1] - old_coordinates[count + 1] != Scalar(0) ||
        tri_coordinates[count + 2] - old_coordinates[count + 2] != Scalar(0)  )
      {
        cout << endl << "DH_deprecated_api_test: FAILED." << endl << endl;
        exit(EXIT_FAILURE);
      }
      count += 3;
    }
  }

  cout << endl << "DH_deprecated_api_test: PASSED." << endl << endl;
  return EXIT_SUCCESS;
}
