// This file is part of libigl, a simple c++ geometry processing library.
// 
// Copyright (C) 2015 Qingnan Zhou <qnzhou@gmail.com>
// 
// This Source Code Form is subject to the terms of the Mozilla Public License 
// v. 2.0. If a copy of the MPL was not distributed with this file, You can 
// obtain one at http://mozilla.org/MPL/2.0/.
//
#ifndef IGL_COPYLEFT_CGAL_BINARY_WINDING_NUMBER_OPERATIONS_H
#define IGL_COPYLEFT_CGAL_BINARY_WINDING_NUMBER_OPERATIONS_H

#include <stdexcept>
#include "../../igl_inline.h"
#include "../../MeshBooleanType.h"
#include <Eigen/Core>

// TODO: This is not written according to libigl style. These should be
// function handles.
//
// Why is this templated on DerivedW
namespace igl
{
  namespace copyleft
  {
    namespace cgal
    {
      template <igl::MeshBooleanType Op>
      class BinaryWindingNumberOperations {
        public:
          template<typename DerivedW>
            typename DerivedW::Scalar operator()(
                const Eigen::PlainObjectBase<DerivedW>& /*win_nums*/) const {
              throw (std::runtime_error("not implemented!"));
            }
      };

      template <>
      class BinaryWindingNumberOperations<MESH_BOOLEAN_TYPE_UNION> {
        public:
          template<typename DerivedW>
          typename DerivedW::Scalar operator()(
              const Eigen::PlainObjectBase<DerivedW>& win_nums) const {
            return win_nums(0) > 0 || win_nums(1) > 0;
          }
      };

      template <>
      class BinaryWindingNumberOperations<MESH_BOOLEAN_TYPE_INTERSECT> {
        public:
          template<typename DerivedW>
          typename DerivedW::Scalar operator()(
              const Eigen::PlainObjectBase<DerivedW>& win_nums) const {
            return win_nums(0) > 0 && win_nums(1) > 0;
          }
      };

      template <>
      class BinaryWindingNumberOperations<MESH_BOOLEAN_TYPE_MINUS> {
        public:
          template<typename DerivedW>
          typename DerivedW::Scalar operator()(
              const Eigen::PlainObjectBase<DerivedW>& win_nums) const {
            return win_nums(0) > 0 && win_nums(1) <= 0;
          }
      };

      template <>
      class BinaryWindingNumberOperations<MESH_BOOLEAN_TYPE_XOR> {
        public:
          template<typename DerivedW>
          typename DerivedW::Scalar operator()(
              const Eigen::PlainObjectBase<DerivedW>& win_nums) const {
            return (win_nums(0) > 0 && win_nums(1) <= 0) ||
              (win_nums(0) <= 0 && win_nums(1) > 0);
          }
      };

      template <>
      class BinaryWindingNumberOperations<MESH_BOOLEAN_TYPE_RESOLVE> {
        public:
          template<typename DerivedW>
            typename DerivedW::Scalar operator()(
                const Eigen::PlainObjectBase<DerivedW>& /*win_nums*/) const {
              return true;
            }
      };

      typedef BinaryWindingNumberOperations<MESH_BOOLEAN_TYPE_UNION> BinaryUnion;
      typedef BinaryWindingNumberOperations<MESH_BOOLEAN_TYPE_INTERSECT> BinaryIntersect;
      typedef BinaryWindingNumberOperations<MESH_BOOLEAN_TYPE_MINUS> BinaryMinus;
      typedef BinaryWindingNumberOperations<MESH_BOOLEAN_TYPE_XOR> BinaryXor;
      typedef BinaryWindingNumberOperations<MESH_BOOLEAN_TYPE_RESOLVE> BinaryResolve;

      enum KeeperType {
        KEEP_INSIDE,
        KEEP_ALL
      };

      template<KeeperType T>
      class WindingNumberFilter {
        public:
          template<typename DerivedW>
            short operator()(
                const Eigen::PlainObjectBase<DerivedW>& /*win_nums*/) const {
              throw std::runtime_error("Not implemented");
            }
      };

      template<>
      class WindingNumberFilter<KEEP_INSIDE> {
        public:
          template<typename T>
          short operator()(T out_w, T in_w) const {
            if (in_w > 0 && out_w <= 0) return 1;
            else if (in_w <= 0 && out_w > 0) return -1;
            else return 0;
          }
      };

      template<>
      class WindingNumberFilter<KEEP_ALL> {
        public:
          template<typename T>
            short operator()(T /*out_w*/, T /*in_w*/) const {
              return 1;
            }
      };

      typedef WindingNumberFilter<KEEP_INSIDE> KeepInside;
      typedef WindingNumberFilter<KEEP_ALL> KeepAll;
    }
  }
}

#endif