#include <retrieveHitTruthInfo.hxx>
#include <IMCDigit.hxx>
#include <IMCHit.hxx>
#include <IComboHit.hxx>
#include <IReconHit.hxx>
#include <IMultiHit.hxx>
#include <algorithm>
#include <iterator>
#include <set>

std::vector<COMET::IG4VHit*> HitTruthInfo::GetHitTruthInfo(COMET::IHandle<COMET::IHit> hit){

  // Check if we have MC-digit information.
  if(hit->GetDigitCount()){
    COMET::IDigitProxy proxy = hit->GetDigit();
    COMET::IMCDigit *mcDigit = proxy.As<COMET::IMCDigit>();  

    if(mcDigit){
      return mcDigit->GetContributors();
    }
  }

  // Check if this is a IMCHit.
  COMET::IHandle<COMET::IMCHit> mcchit = hit;
  if(mcchit){
    return mcchit->GetContributors();
  }
  
  // Unpack multihits and use a unique set of contributors
  COMET::IHandle<COMET::IMultiHit> multihit = hit;
  if (multihit) {
    std::set<COMET::IG4VHit*> contrset;
    COMET::IMultiHit::iterator hit2 = multihit->begin();
    std::vector<COMET::IG4VHit*> contr = GetHitTruthInfo(*hit2);
    for (std::vector<COMET::IG4VHit*>::iterator c = contr.begin(); c != contr.end(); c++)
       contrset.insert(*c);
    std::vector<COMET::IG4VHit*> result;
    std::copy(contrset.begin(), contrset.end(), std::back_inserter(result));
    return result;
  }

  // Now check if it is a IComboHit and expand
  COMET::IHandle<COMET::IComboHit> combohit(hit);
  if (combohit) {
    std::vector<COMET::IG4VHit*> result;
    for (COMET::IHitSelection::const_iterator hit2 = combohit->GetHits().begin();
	 hit2 != combohit->GetHits().end(); hit2++) {
      // use a recursive call to get the constituents of the combo hit
      std::vector<COMET::IG4VHit*> constituents = GetHitTruthInfo(*hit2);
      std::copy(constituents.begin(), constituents.end(), std::back_inserter(result));
    }
    return result;
  }

  // Now check if it is a IReconHit and expand
  COMET::IHandle<COMET::IReconHit> recohit(hit);
  if (recohit) {
    std::vector<COMET::IG4VHit*> result;
    for ( int i=0; i < hit->GetContributorCount(); i++){
      std::vector<COMET::IG4VHit*> constituents = GetHitTruthInfo(hit->GetContributor(i));
      std::copy(constituents.begin(), constituents.end(), std::back_inserter(result));
    }
    return result;
  }



  return std::vector<COMET::IG4VHit*>();


};