#include "Rivet/Analysis.hh"
#include "Rivet/Projections/FinalState.hh"
#include "Rivet/Projections/ChargedFinalState.hh"

namespace Rivet {


  class MyAnalysis : public Analysis {
  public:

    DEFAULT_RIVET_ANALYSIS_CTOR(MyAnalysis);
    void init() {
      const ChargedFinalState cfs(-0.8, 0.8, 0.0*GeV);
      declare(cfs, "CFS");

      //_Nevt_after_cuts_orveto = 0;

      _h_dNch_dPt = bookHisto1D("PtCh", 200, 0, 100);

    }

    void analyze(const Event& event) {
      const double weight = event.weight();
      int count_plus = 0;
      const ChargedFinalState& charged = apply<ChargedFinalState>(event, "CFS");
      
      foreach (const Particle& p, charged.particles()) {
        const double abseta = fabs(p.eta());
        if (abseta < 0.8) count_plus++;
        const double pT = p.perp()/GeV;  
        if ( count_plus > 0 )  {
          //_Nevt_after_cuts_orveto += weight;
          _h_dNch_dPt->fill(pT, weight);
        }
      }     
    }
    
    
    void finalize() {
      //const double norm_orveto = 1.0/_Nevt_after_cuts_orveto;
      scale(_h_dNch_dPt,  crossSection()/millibarn/sumOfWeights());
    }


  private:

    Histo1DPtr _h_dNch_dPt;
      
    //double _Nevt_after_cuts_orveto;

  };

  DECLARE_RIVET_PLUGIN(MyAnalysis);

}