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#ifndef PCL_REGISTRATION_IMPL_CORRESPONDENCE_ESTIMATION_H_
#define PCL_REGISTRATION_IMPL_CORRESPONDENCE_ESTIMATION_H_

#include <pcl/common/copy_point.h>
#include <pcl/common/io.h>

namespace pcl {

namespace registration {

template <typename PointSource, typename PointTarget, typename Scalar>
void
CorrespondenceEstimationBase<PointSource, PointTarget, Scalar>::setInputTarget(
    const PointCloudTargetConstPtr& cloud)
{
  if (cloud->points.empty()) {
    PCL_ERROR("[pcl::registration::%s::setInputTarget] Invalid or empty point cloud "
              "dataset given!\n",
              getClassName().c_str());
    return;
  }
  target_ = cloud;

  // Set the internal point representation of choice
  if (point_representation_)
    tree_->setPointRepresentation(point_representation_);

  target_cloud_updated_ = true;
}

template <typename PointSource, typename PointTarget, typename Scalar>
bool
CorrespondenceEstimationBase<PointSource, PointTarget, Scalar>::initCompute()
{
  if (!target_) {
    PCL_ERROR("[pcl::registration::%s::compute] No input target dataset was given!\n",
              getClassName().c_str());
    return (false);
  }

  // Only update target kd-tree if a new target cloud was set
  if (target_cloud_updated_ && !force_no_recompute_) {
    // If the target indices have been given via setIndicesTarget
    if (target_indices_)
      tree_->setInputCloud(target_, target_indices_);
    else
      tree_->setInputCloud(target_);

    target_cloud_updated_ = false;
  }

  return (PCLBase<PointSource>::initCompute());
}

template <typename PointSource, typename PointTarget, typename Scalar>
bool
CorrespondenceEstimationBase<PointSource, PointTarget, Scalar>::initComputeReciprocal()
{
  // Only update source kd-tree if a new target cloud was set
  if (source_cloud_updated_ && !force_no_recompute_reciprocal_) {
    if (point_representation_reciprocal_)
      tree_reciprocal_->setPointRepresentation(point_representation_reciprocal_);
    // If the target indices have been given via setIndicesTarget
    if (indices_)
      tree_reciprocal_->setInputCloud(getInputSource(), getIndicesSource());
    else
      tree_reciprocal_->setInputCloud(getInputSource());

    source_cloud_updated_ = false;
  }

  return (true);
}

namespace detail {

template <
    typename PointTarget,
    typename PointSource,
    typename Index,
    typename std::enable_if_t<isSamePointType<PointSource, PointTarget>()>* = nullptr>
const PointSource&
pointCopyOrRef(typename pcl::PointCloud<PointSource>::ConstPtr& input, const Index& idx)
{
  return (*input)[idx];
}

template <
    typename PointTarget,
    typename PointSource,
    typename Index,
    typename std::enable_if_t<!isSamePointType<PointSource, PointTarget>()>* = nullptr>
PointTarget
pointCopyOrRef(typename pcl::PointCloud<PointSource>::ConstPtr& input, const Index& idx)
{
  // Copy the source data to a target PointTarget format so we can search in the tree
  PointTarget pt;
  copyPoint((*input)[idx], pt);
  return pt;
}

} // namespace detail

template <typename PointSource, typename PointTarget, typename Scalar>
void
CorrespondenceEstimation<PointSource, PointTarget, Scalar>::determineCorrespondences(
    pcl::Correspondences& correspondences, double max_distance)
{
  if (!initCompute())
    return;

  correspondences.resize(indices_->size());

  pcl::Indices index(1);
  std::vector<float> distance(1);
  pcl::Correspondence corr;
  unsigned int nr_valid_correspondences = 0;
  double max_dist_sqr = max_distance * max_distance;

  // Iterate over the input set of source indices
  for (const auto& idx : (*indices_)) {
    // Check if the template types are the same. If true, avoid a copy.
    // Both point types MUST be registered using the POINT_CLOUD_REGISTER_POINT_STRUCT
    // macro!
    const auto& pt = detail::pointCopyOrRef<PointTarget, PointSource>(input_, idx);
    tree_->nearestKSearch(pt, 1, index, distance);
    if (distance[0] > max_dist_sqr)
      continue;

    corr.index_query = idx;
    corr.index_match = index[0];
    corr.distance = distance[0];
    correspondences[nr_valid_correspondences++] = corr;
  }

  correspondences.resize(nr_valid_correspondences);
  deinitCompute();
}

template <typename PointSource, typename PointTarget, typename Scalar>
void
CorrespondenceEstimation<PointSource, PointTarget, Scalar>::
    determineReciprocalCorrespondences(pcl::Correspondences& correspondences,
                                       double max_distance)
{
  if (!initCompute())
    return;

  // setup tree for reciprocal search
  // Set the internal point representation of choice
  if (!initComputeReciprocal())
    return;
  double max_dist_sqr = max_distance * max_distance;

  correspondences.resize(indices_->size());
  pcl::Indices index(1);
  std::vector<float> distance(1);
  pcl::Indices index_reciprocal(1);
  std::vector<float> distance_reciprocal(1);
  pcl::Correspondence corr;
  unsigned int nr_valid_correspondences = 0;
  int target_idx = 0;

  // Iterate over the input set of source indices
  for (const auto& idx : (*indices_)) {
    // Check if the template types are the same. If true, avoid a copy.
    // Both point types MUST be registered using the POINT_CLOUD_REGISTER_POINT_STRUCT
    // macro!

    const auto& pt_src = detail::pointCopyOrRef<PointTarget, PointSource>(input_, idx);

    tree_->nearestKSearch(pt_src, 1, index, distance);
    if (distance[0] > max_dist_sqr)
      continue;

    target_idx = index[0];
    const auto& pt_tgt =
        detail::pointCopyOrRef<PointSource, PointTarget>(target_, target_idx);

    tree_reciprocal_->nearestKSearch(pt_tgt, 1, index_reciprocal, distance_reciprocal);
    if (distance_reciprocal[0] > max_dist_sqr || idx != index_reciprocal[0])
      continue;

    corr.index_query = idx;
    corr.index_match = index[0];
    corr.distance = distance[0];
    correspondences[nr_valid_correspondences++] = corr;
  }
  correspondences.resize(nr_valid_correspondences);
  deinitCompute();
}

} // namespace registration
} // namespace pcl

//#define PCL_INSTANTIATE_CorrespondenceEstimation(T,U) template class PCL_EXPORTS
// pcl::registration::CorrespondenceEstimation<T,U>;

#endif /* PCL_REGISTRATION_IMPL_CORRESPONDENCE_ESTIMATION_H_ */
