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#ifndef PCL_RECOGNITION_CORRESPONDENCE_GROUPING_H_
#define PCL_RECOGNITION_CORRESPONDENCE_GROUPING_H_

#include <pcl/pcl_base.h>
#include <pcl/correspondence.h>
#include <pcl/console/print.h>

namespace pcl
{
  /** \brief Abstract base class for Correspondence Grouping algorithms.
    *
    * \author Tommaso Cavallari, Federico Tombari, Aitor Aldoma
    * \ingroup recognition
    */
  template <typename PointModelT, typename PointSceneT>
  class CorrespondenceGrouping : public PCLBase<PointModelT>
  {
    public:
      typedef pcl::PointCloud<PointSceneT> SceneCloud;
      typedef typename SceneCloud::Ptr SceneCloudPtr;
      typedef typename SceneCloud::ConstPtr SceneCloudConstPtr;

      /** \brief Empty constructor. */
      CorrespondenceGrouping () : scene_ (), model_scene_corrs_ () {}

      /** \brief destructor. */
      virtual ~CorrespondenceGrouping() 
      {
        scene_.reset ();
        model_scene_corrs_.reset ();
      }

      /** \brief Provide a pointer to the scene dataset.
        * 
        * \param[in] scene the const boost shared pointer to a PointCloud message.
        */
      virtual inline void
      setSceneCloud (const SceneCloudConstPtr &scene)
      {
        scene_ = scene;
      }

      /** \brief Getter for the scene dataset.
        * 
        * \return the const boost shared pointer to a PointCloud message.
        */
      inline SceneCloudConstPtr
      getSceneCloud () const
      {
        return (scene_);
      }

      /** \brief Provide a pointer to the precomputed correspondences between points in the input dataset and 
        * points in the scene dataset. The correspondences are going to be clustered into different model hypotheses
        * by the algorithm.
        * 
        * \param[in] corrs the correspondences between the model and the scene.
        */
      virtual inline void
      setModelSceneCorrespondences (const CorrespondencesConstPtr &corrs)
      {
        model_scene_corrs_ = corrs;
      }

      /** \brief Getter for the precomputed correspondences between points in the input dataset and 
        * points in the scene dataset. 
        * 
        * \return the correspondences between the model and the scene.
        */
      inline CorrespondencesConstPtr
      getModelSceneCorrespondences () const
      {
        return (model_scene_corrs_);
      }

	   /** \brief Getter for the vector of characteristic scales associated to each cluster
        * 
        * \return the vector of characteristic scales (assuming scale = model / scene)
        */
      inline std::vector<double>
      getCharacteristicScales () const
      {
        return (corr_group_scale_);
      }

      /** \brief Clusters the input correspondences belonging to different model instances.
        *
        * \param[out] clustered_corrs a vector containing the correspondences for each instance of the model found within the input data.
        */
      void
      cluster (std::vector<Correspondences> &clustered_corrs);

    protected:
      /** \brief The scene cloud. */
      SceneCloudConstPtr scene_;

      using PCLBase<PointModelT>::input_;

      /** \brief The correspondences between points in the input and the scene datasets. */
      CorrespondencesConstPtr model_scene_corrs_;

	  /** \brief characteristic scale associated to each correspondence subset; 
		* if the cg algorithm can not handle scale invariance, the size of the vector will be 0. */
	  std::vector <double> corr_group_scale_;

      /** \brief The actual clustering method, should be implemented by each subclass.
        *
        * \param[out] clustered_corrs a vector containing the correspondences for each instance of the model found within the input data.
        */
      virtual void
      clusterCorrespondences (std::vector<Correspondences> &clustered_corrs) = 0;

      /** \brief This method should get called before starting the actual computation. 
        *
        * Internally, initCompute() does the following:
        *   - checks if an input dataset is given, and returns false otherwise
        *   - checks if a scene dataset is given, and returns false otherwise
        *   - checks if the model-scene correspondences have been given, and returns false otherwise
        */
      inline bool
      initCompute ()
      {
        if (!PCLBase<PointModelT>::initCompute ())
        {
          return (false);
        }

        if (!scene_)
        {
          PCL_ERROR ("[initCompute] Scene not set.\n");
          return (false);
        }

        if (!input_)
        {
          PCL_ERROR ("[initCompute] Input not set.\n");
          return (false);
        }

        if (!model_scene_corrs_)
        {
          PCL_ERROR ("[initCompute] Model-Scene Correspondences not set.\n");
          return (false);
        }

        return (true);
      }

      /** \brief This method should get called after finishing the actual computation. 
        *
        */
      inline bool
      deinitCompute ()
      {
        return (true);
      }

  };
}

#include <pcl/recognition/impl/cg/correspondence_grouping.hpp>

#endif // PCL_RECOGNITION_CORRESPONDENCE_GROUPING_H_
