/* Copyright (c) 2018 PaddlePaddle Authors. All Rights Reserved.

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License. */

#ifndef POLY_UTIL_CC_
#define POLY_UTIL_CC_

#include "paddle/fluid/operators/detection/poly_util.h"
#include "paddle/fluid/framework/op_registry.h"

namespace paddle {
namespace operators {

using gpc::gpc_polygon_clip;
using gpc::gpc_free_polygon;

template <class T>
void Array2PointVec(const T*& box, const size_t box_size,
                    std::vector<Point_<T>>& vec) {
  size_t pts_num = box_size / 2;
  vec.resize(pts_num);
  for (size_t i = 0; i < pts_num; i++) {
    vec.at(i).x = box[2 * i];
    vec.at(i).y = box[2 * i + 1];
  }
}

template <class T>
void Array2Poly(const T*& box, const size_t box_size, gpc::gpc_polygon& poly) {
  size_t pts_num = box_size / 2;
  poly.num_contours = 1;
  poly.hole = (int*)malloc(sizeof(int));
  poly.hole[0] = 0;
  poly.contour = (gpc::gpc_vertex_list*)malloc(sizeof(gpc::gpc_vertex_list));
  poly.contour->num_vertices = pts_num;
  poly.contour->vertex =
      (gpc::gpc_vertex*)malloc(sizeof(gpc::gpc_vertex) * pts_num);
  for (size_t i = 0; i < pts_num; ++i) {
    poly.contour->vertex[i].x = box[2 * i];
    poly.contour->vertex[i].y = box[2 * i + 1];
  }
}

template <class T>
void PointVec2Poly(const std::vector<Point_<T>>& vec, gpc::gpc_polygon& poly) {
  int pts_num = vec.size();
  poly.num_contours = 1;
  poly.hole = (int*)malloc(sizeof(int));
  poly.hole[0] = 0;
  poly.contour = (gpc::gpc_vertex_list*)malloc(sizeof(gpc::gpc_vertex_list));
  poly.contour->num_vertices = pts_num;
  poly.contour->vertex =
      (gpc::gpc_vertex*)malloc(sizeof(gpc::gpc_vertex) * pts_num);
  for (size_t i = 0; i < pts_num; ++i) {
    poly.contour->vertex[i].x = vec[i].x;
    poly.contour->vertex[i].y = vec[i].y;
  }
}

template <class T>
void Poly2PointVec(const gpc::gpc_vertex_list& contour,
                   std::vector<Point_<T>>& vec) {
  int pts_num = contour.num_vertices;
  vec.resize(pts_num);
  for (int i = 0; i < pts_num; i++) {
    vec.at(i).x = contour.vertex[i].x;
    vec.at(i).y = contour.vertex[i].y;
  }
}

template <class T>
T GetContourArea(std::vector<Point_<T>>& vec) {
  size_t pts_num = vec.size();
  if (pts_num < 3) return T(0.);
  T area = T(0.);
  for (size_t i = 0; i < pts_num; ++i) {
    area += vec[i].x * vec[(i + 1) % pts_num].y -
            vec[i].y * vec[(i + 1) % pts_num].x;
  }
  return std::fabs(area / 2.0);
}

template <class T>
T PolyArea(const T* box, const size_t box_size, const bool normalized) {
  // If coordinate values are is invalid
  // if area size <= 0,  return 0.
  std::vector<Point_<T>> vec;
  Array2PointVec<T>(box, box_size, vec);
  return GetContourArea<T>(vec);
}

template <class T>
T PolyOverlapArea(const T* box1, const T* box2, const size_t box_size,
                  const bool normalized) {
  gpc::gpc_polygon poly1;
  gpc::gpc_polygon poly2;
  Array2Poly<T>(box1, box_size, poly1);
  Array2Poly<T>(box2, box_size, poly2);
  gpc::gpc_polygon respoly;
  gpc::gpc_op op = gpc::GPC_INT;
  gpc::gpc_polygon_clip(op, &poly2, &poly1, &respoly);

  T inter_area = T(0.);
  int contour_num = respoly.num_contours;
  for (int i = 0; i < contour_num; ++i) {
    std::vector<Point_<T>> resvec;
    Poly2PointVec<T>(respoly.contour[i], resvec);
    // inter_area += std::fabs(cv::contourArea(resvec)) + 0.5f *
    // (cv::arcLength(resvec, true));
    inter_area += GetContourArea<T>(resvec);
  }

  gpc::gpc_free_polygon(&poly1);
  gpc::gpc_free_polygon(&poly2);
  gpc::gpc_free_polygon(&respoly);
  return inter_area;
}

}  // namespace operators
}  // namespace paddle

#endif
