////////////////////////////////////////////////////////////////////
/// \file geoprint.cc
///
/// \brief Extracts step lengths from tracking
///
/// \author P G Jones <p.g.jones@qmul.ac.uk>
///
/// REVISION HISTORY:\n
///     2014-05-29 : P G Jones - Added header information.\n
///     2016-10-19 : M Stringer - Changes to how MCTracks are accessed (PR #1508).
//      2018-02-10 : R Lane - change to function arguments necessary for ROOT 6 compatibility
///
/// \details The step lengths are dependent on the geometry.
///
////////////////////////////////////////////////////////////////////

#include <RAT/DU/DSReader.hh>
#include <RAT/DS/Entry.hh>
#include <RAT/DS/MC.hh>
#include <RAT/DS/MCPMT.hh>
#include <RAT/DS/MCPE.hh>

#include <TH1D.h>
#include <TFile.h>

void geoprint(std::string event_file, std::string outfile)
{
  RAT::DU::DSReader* dsReader = new RAT::DU::DSReader(event_file);
  TFile *outtfile = new TFile(outfile.c_str(),"RECREATE");

  TH1D* stepSize = new TH1D("hStepSize", "Distance between volume boundaries for isotropic particle tracks", 1000, 0, 3500);
  stepSize->SetYTitle("Events per bin");
  stepSize->SetXTitle("Distance between volume boundaries (mm)");

  for( size_t iEntry = 0; iEntry < dsReader->GetEntryCount(); iEntry++ )
    {
      const RAT::DS::Entry& rDS = dsReader->GetEntry( iEntry );
      const RAT::DS::MC& rMC = rDS.GetMC();
      std::vector<unsigned int> mcTrackIDs = rMC.GetMCTrackIDs();
      for( size_t iTrack = 0; iTrack < mcTrackIDs.size(); iTrack++ )
        {
          const RAT::DS::MCTrack& rMCTrack = rMC.GetMCTrack( mcTrackIDs.at(iTrack) );
          for( size_t iStep = 0; iStep < rMCTrack.GetMCTrackStepCount(); iStep++ )
            stepSize->Fill( rMCTrack.GetMCTrackStep( iStep ).GetLength() );
        }
    }

  stepSize->SetMinimum(0);
  outtfile->cd();
  stepSize->Write();
  outtfile->Close();
  delete outtfile;
  delete dsReader;
}