#include <algorithm>

void SciFiSpacePointRec::look_for_duplets_npe(SciFiEvent &evt,

					      std::vector<SciFiCluster*> (&clusters)[2][6][3]) const {

  for ( int Tracker = 0; Tracker < 2; Tracker++ ) {  // for each tracker

    for ( int Station = 0; Station < 6; Station++ ) {  // for each station

      // Make a list of all clusters in the station:

      std::vector<SciFiCluster*> station_clusters;

      for ( int a_plane = 0; a_plane < 3; a_plane++ )

	station_clusters.insert(station_clusters.end(),

				clusters[Tracker][Station][a_plane].begin(),

				clusters[Tracker][Station][a_plane].end());

      // Sort clusters in NPE order:

      std::sort(station_clusters.begin(), station_clusters.end(), 

		[](const SciFiCluster* a, const SciFiCluster* b) -> bool{ 

		  return a->get_npe() > b->get_npe(); 

		});

      //debug print statememnt

      //int unused = 0;

      //for (auto c : station_clusters) if (not c->is_used()) unused++;

      //if (unused > 1){

      //

      //	std::cerr << std::endl;

      //	std::cerr << "T:" << Tracker << " S:" << Station << std::endl;

      //	std::cerr << "LY: ";

      //	for (auto c : station_clusters) std::cerr << c->get_npe() << ", ";

      //	std::cerr << std::endl;

      //}

      // Iterate over clusters in NPE order to make duplets:

      for (auto a_it = station_clusters.begin(); a_it != station_clusters.end(); ++a_it){

	SciFiCluster* candidate_A = (*a_it);

	// Inner iteration over other candidates:

	for (auto b_it = station_clusters.begin(); b_it != station_clusters.end(); ++b_it){

	  SciFiCluster* candidate_B = (*b_it);

	  if ( clusters_are_not_used(candidate_A, candidate_B) &&

	       candidate_A->get_plane() != candidate_B->get_plane() &&

	       duplet_within_radius(candidate_A, candidate_B) ) {

	    //std::cerr << "DP: " << candidate_A->get_npe() << ", " << candidate_B->get_npe() << std::endl;

	    SciFiSpacePoint* duplet = new SciFiSpacePoint(candidate_A, candidate_B);

	    build_duplet(duplet);

	    evt.add_spacepoint(duplet);

	    break;

	  }

	}

      }

    }

  }

}