#pragma once

#include <pcl/pcl_base.h>

namespace pcl {

namespace tracking {

/** \brief @b PointCoherence is a base class to compute coherence between the
 * two points.
 * \author Ryohei Ueda
 * \ingroup tracking
 */
template <typename PointInT>
class PointCoherence {
public:
  using Ptr = shared_ptr<PointCoherence<PointInT>>;
  using ConstPtr = shared_ptr<const PointCoherence<PointInT>>;

public:
  /** \brief empty constructor */
  PointCoherence() = default;

  /** \brief empty distructor */
  virtual ~PointCoherence() = default;

  /** \brief compute coherence from the source point to the target point.
   * \param source instance of source point.
   * \param target instance of target point.
   */
  inline double
  compute(PointInT& source, PointInT& target);

protected:
  /** \brief The coherence name. */
  std::string coherence_name_;

  /** \brief abstract method to calculate coherence.
   * \param[in] source instance of source point.
   * \param[in] target instance of target point.
   */
  virtual double
  computeCoherence(PointInT& source, PointInT& target) = 0;

  /** \brief Get a string representation of the name of this class. */
  inline const std::string&
  getClassName() const
  {
    return (coherence_name_);
  }
};

/** \brief @b PointCloudCoherence is a base class to compute coherence between
 * the two PointClouds.
 * \author Ryohei Ueda
 * \ingroup tracking
 */
template <typename PointInT>
class PointCloudCoherence {
public:
  using Ptr = shared_ptr<PointCloudCoherence<PointInT>>;
  using ConstPtr = shared_ptr<const PointCloudCoherence<PointInT>>;

  using PointCloudIn = pcl::PointCloud<PointInT>;
  using PointCloudInPtr = typename PointCloudIn::Ptr;
  using PointCloudInConstPtr = typename PointCloudIn::ConstPtr;

  using PointCoherencePtr = typename PointCoherence<PointInT>::Ptr;
  /** \brief Constructor. */
  PointCloudCoherence() : target_input_(), point_coherences_() {}

  /** \brief Destructor. */
  virtual ~PointCloudCoherence() = default;

  /** \brief compute coherence between two pointclouds. */
  inline void
  compute(const PointCloudInConstPtr& cloud,
          const IndicesConstPtr& indices,
          float& w_i);

  /** \brief get a list of pcl::tracking::PointCoherence.*/
  inline std::vector<PointCoherencePtr>
  getPointCoherences()
  {
    return point_coherences_;
  }

  /** \brief set a list of pcl::tracking::PointCoherence.
   * \param coherences a list of pcl::tracking::PointCoherence.
   */
  inline void
  setPointCoherences(std::vector<PointCoherencePtr> coherences)
  {
    point_coherences_ = coherences;
  }

  /** \brief This method should get called before starting the actual
   * computation. */
  virtual bool
  initCompute();

  /** \brief add a PointCoherence to the PointCloudCoherence.
   * \param coherence a pointer to PointCoherence.
   */
  inline void
  addPointCoherence(PointCoherencePtr coherence)
  {
    point_coherences_.push_back(coherence);
  }

  /** \brief add a PointCoherence to the PointCloudCoherence.
   * \param cloud a pointer to PointCoherence.
   */
  virtual inline void
  setTargetCloud(const PointCloudInConstPtr& cloud)
  {
    target_input_ = cloud;
  }

protected:
  /** \brief Abstract method to compute coherence. */
  virtual void
  computeCoherence(const PointCloudInConstPtr& cloud,
                   const IndicesConstPtr& indices,
                   float& w_j) = 0;

  inline double
  calcPointCoherence(PointInT& source, PointInT& target);

  /** \brief Get a string representation of the name of this class. */
  inline const std::string&
  getClassName() const
  {
    return (coherence_name_);
  }

  /** \brief The coherence name. */
  std::string coherence_name_;

  /** \brief a pointer to target point cloud*/
  PointCloudInConstPtr target_input_;

  /** \brief a list of pointers to PointCoherence.*/
  std::vector<PointCoherencePtr> point_coherences_;
};

} // namespace tracking
} // namespace pcl

#include <pcl/tracking/impl/coherence.hpp>
