#ifndef IGL_FAST_WINDING_NUMBER
#define IGL_FAST_WINDING_NUMBER
#include "igl_inline.h"
#include "FastWindingNumberForSoups.h"
#include <Eigen/Core>
#include <vector>
namespace igl
{
  /// Generate the precomputation for the fast winding number for point data
  /// [Barill et. al 2018].
  ///
  /// Given a set of 3D points P, with normals N, areas A, along with octree
  /// data, and an expansion order, we define a taylor series expansion at each
  /// octree cell.
  ///
  /// The octree data is designed to come from igl::octree, and the areas (if not
  /// obtained at scan time), may be calculated using
  /// igl::copyleft::cgal::point_areas.
  ///
  /// @param[in] P  #P by 3 list of point locations
  /// @param[in] N  #P by 3 list of point normals
  /// @param[in] A  #P by 1 list of point areas
  /// @param[in] point_indices  a vector of vectors, where the ith entry is a vector of
  ///                  the indices into P that are the ith octree cell's points
  /// @param[in] CH             #OctreeCells by 8, where the ith row is the indices of
  ///                  the ith octree cell's children
  /// @param[in] expansion_order    the order of the taylor expansion. We support 0,1,2.
  /// @param[out] CM  #OctreeCells by 3 list of each cell's center of mass
  /// @param[out] R   #OctreeCells by 1 list of each cell's maximum distance of any point
  ///       to the center of mass
  /// @param[out] EC  #OctreeCells by #TaylorCoefficients list of expansion coefficients.
  ///       (Note that #TaylorCoefficients = ∑_{i=1}^{expansion_order} 3^i)
  ///
  /// \see copyleft::cgal::point_areas, knn
  template <
    typename DerivedP, 
    typename DerivedA, 
    typename DerivedN,
    typename Index, 
    typename DerivedCH, 
    typename DerivedCM, 
    typename DerivedR,
    typename DerivedEC>
  IGL_INLINE void fast_winding_number(
    const Eigen::MatrixBase<DerivedP>& P,
    const Eigen::MatrixBase<DerivedN>& N,
    const Eigen::MatrixBase<DerivedA>& A,
    const std::vector<std::vector<Index> > & point_indices,
    const Eigen::MatrixBase<DerivedCH>& CH,
    const int expansion_order,
    Eigen::PlainObjectBase<DerivedCM>& CM,
    Eigen::PlainObjectBase<DerivedR>& R,
    Eigen::PlainObjectBase<DerivedEC>& EC);
  /// Evaluate the fast winding number for point data, having already done the
  /// the precomputation
  ///
  /// @param[in] P  #P by 3 list of point locations
  /// @param[in] N  #P by 3 list of point normals
  /// @param[in] A  #P by 1 list of point areas
  /// @param[in] point_indices  a vector of vectors, where the ith entry is a vector of
  ///                  the indices into P that are the ith octree cell's points
  /// @param[in] CH  #OctreeCells by 8, where the ith row is the indices of
  ///       the ith octree cell's children
  /// @param[in] CM  #OctreeCells by 3 list of each cell's center of mass
  /// @param[in] R   #OctreeCells by 1 list of each cell's maximum distance of any point
  ///       to the center of mass
  /// @param[in] EC  #OctreeCells by #TaylorCoefficients list of expansion coefficients.
  ///        (Note that #TaylorCoefficients = ∑_{i=1}^{expansion_order} 3^i)
  /// @param[in] Q  #Q by 3 list of query points for the winding number
  /// @param[in] beta  This is a Barnes-Hut style accuracy term that separates near feild
  ///         from far field. The higher the beta, the more accurate and slower
  ///         the evaluation. We reccommend using a beta value of 2. Note that
  ///         for a beta value ≤ 0, we use the direct evaluation, rather than
  ///         the fast approximation
  /// @param[out] WN  #Q by 1 list of windinng number values at each query point
  template <
    typename DerivedP, 
    typename DerivedA, 
    typename DerivedN,
    typename Index, 
    typename DerivedCH, 
    typename DerivedCM, 
    typename DerivedR,
    typename DerivedEC, 
    typename DerivedQ, 
    typename BetaType,
    typename DerivedWN>
  IGL_INLINE void fast_winding_number(
    const Eigen::MatrixBase<DerivedP>& P,
    const Eigen::MatrixBase<DerivedN>& N,
    const Eigen::MatrixBase<DerivedA>& A,
    const std::vector<std::vector<Index> > & point_indices,
    const Eigen::MatrixBase<DerivedCH>& CH,
    const Eigen::MatrixBase<DerivedCM>& CM,
    const Eigen::MatrixBase<DerivedR>& R,
    const Eigen::MatrixBase<DerivedEC>& EC,
    const Eigen::MatrixBase<DerivedQ>& Q,
    const BetaType beta,
    Eigen::PlainObjectBase<DerivedWN>& WN);
  /// \overload
  ///
  /// \brief Evaluate the fast winding number for point data without caching the
  /// precomputation.
  template <
    typename DerivedP, 
    typename DerivedA, 
    typename DerivedN,
    typename DerivedQ, 
    typename BetaType, 
    typename DerivedWN>
  IGL_INLINE void fast_winding_number(
    const Eigen::MatrixBase<DerivedP>& P,
    const Eigen::MatrixBase<DerivedN>& N,
    const Eigen::MatrixBase<DerivedA>& A,
    const Eigen::MatrixBase<DerivedQ>& Q,
    const int expansion_order,
    const BetaType beta,
    Eigen::PlainObjectBase<DerivedWN>& WN);
  /// \overload
  template <
    typename DerivedP, 
    typename DerivedA, 
    typename DerivedN,
    typename DerivedQ, 
    typename DerivedWN>
  IGL_INLINE void fast_winding_number(
    const Eigen::MatrixBase<DerivedP>& P,
    const Eigen::MatrixBase<DerivedN>& N,
    const Eigen::MatrixBase<DerivedA>& A,
    const Eigen::MatrixBase<DerivedQ>& Q,
    Eigen::PlainObjectBase<DerivedWN>& WN);
  /// @private
  namespace FastWindingNumber { 
    /// @private
    namespace HDK_Sample{ 
      /// @private
      template <typename T1, typename T2> class UT_SolidAngle;} }
  /// Structure for caching precomputation for fast winding number for triangle
  /// soups
  struct FastWindingNumberBVH {
    /// @private
    FastWindingNumber::HDK_Sample::UT_SolidAngle<float,float> ut_solid_angle;
    // Need copies of these so they stay alive between calls.
    /// @private
    std::vector<FastWindingNumber::HDK_Sample::UT_Vector3T<float> > U;
    std::vector<int> F;
  };
  /// Compute approximate winding number of a triangle soup mesh according to
  /// "Fast Winding Numbers for Soups and Clouds" [Barill et al. 2018].
  ///
  /// @param[in] V  #V by 3 list of mesh vertex positions
  /// @param[in] F  #F by 3 list of triangle mesh indices into rows of V
  /// @param[in] Q  #Q by 3 list of query positions
  /// @param[out] W  #Q list of winding number values
  template <
    typename DerivedV,
    typename DerivedF,
    typename DerivedQ,
    typename DerivedW>
  IGL_INLINE void fast_winding_number(
    const Eigen::MatrixBase<DerivedV> & V,
    const Eigen::MatrixBase<DerivedF> & F,
    const Eigen::MatrixBase<DerivedQ> & Q,
    Eigen::PlainObjectBase<DerivedW> & W);
  /// Precomputation for computing approximate winding numbers of a triangle
  /// soup.
  ///
  /// @param[in] V  #V by 3 list of mesh vertex positions
  /// @param[in] F  #F by 3 list of triangle mesh indices into rows of V
  /// @param[in] order  Taylor series expansion order to use (e.g., 2)
  /// @param[out] fwn_bvh  Precomputed bounding volume hierarchy
  ///   
  template <
    typename DerivedV,
    typename DerivedF>
  IGL_INLINE void fast_winding_number(
    const Eigen::MatrixBase<DerivedV> & V,
    const Eigen::MatrixBase<DerivedF> & F,
    const int order,
    FastWindingNumberBVH & fwn_bvh);
  /// After precomputation, compute winding number at a each of many points in a
  /// list.
  ///
  /// @param[in] fwn_bvh  Precomputed bounding volume hierarchy
  /// @param[in] accuracy_scale  parameter controlling accuracy (e.g., 2)
  /// @param[in] Q  #Q by 3 list of query positions
  /// @param[out] W  #Q list of winding number values
  template <
    typename DerivedQ,
    typename DerivedW>
  IGL_INLINE void fast_winding_number(
    const FastWindingNumberBVH & fwn_bvh,
    const float accuracy_scale,
    const Eigen::MatrixBase<DerivedQ> & Q,
    Eigen::PlainObjectBase<DerivedW> & W);
  /// After precomputation, compute winding number at a single point
  ///
  /// @param[in] fwn_bvh  Precomputed bounding volume hierarchy
  /// @param[in] accuracy_scale  parameter controlling accuracy (e.g., 2)
  /// @param[in] p single position
  /// @return w  winding number of this point
  template <typename Derivedp>
  IGL_INLINE typename Derivedp::Scalar fast_winding_number(
    const FastWindingNumberBVH & fwn_bvh,
    const float accuracy_scale,
    const Eigen::MatrixBase<Derivedp> & p);
}
#ifndef IGL_STATIC_LIBRARY
#  include "fast_winding_number.cpp"
#endif

#endif