///////////////////////////////////////////////////////////////////////////////
/// \file detection.cc
///
/// \brief This extracts the MC Photoelectron count
///
/// \author P G Jones <p.g.jones@qmul.ac.uk>
///
/// REVISION HISTORY:\n
///     2014-07-21 : P G Jones - moved to rat-tools validation.\n
//      2018-02-10 : R Lane - change to function arguments necessary for ROOT 6 compatibility
///
/// \details This plots the number of photoelectrons, i.e. the number of photons
/// that hit the photocathode and are absorbed.
///
///////////////////////////////////////////////////////////////////////////////
#include <RAT/DU/DSReader.hh>
#include <RAT/DS/Entry.hh>

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

void detection(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* hNhits = new TH1D( "nHits", "nHits", 200, 0.0, 2000.0 );
  hNhits->SetXTitle( "Number of hits per event." );
  hNhits->SetYTitle( "Count per 10 hit bin." );

  for( size_t iEntry = 0; iEntry < dsReader->GetEntryCount(); iEntry++ )
    {
      const RAT::DS::Entry& rDS = dsReader->GetEntry( iEntry );
      hNhits->Fill( rDS.GetMC().GetMCPECount() );
    }

  outtfile->cd();
  hNhits->Write();
  outtfile->Close();
  delete outtfile;
  delete dsReader;
}