// -*- C++ -*-
#include "Rivet/Analysis.hh"
#include "Rivet/RivetAIDA.hh"
#include "Rivet/Tools/Logging.hh"
#include "Rivet/Projections/FinalState.hh"
#include "Rivet/Projections/ZFinder.hh"


namespace Rivet {

  /// @brief Measurement of Z(->muon muon) pT differential cross-section
  /// @author
  class MUONANALYSIS : public Analysis { 

  public:

    /// @name Construction
    //@{
    /// Constructor
    MUONANALYSIS() : Analysis("MUONANALYSIS")
    {
      setBeams(PROTON, ANTIPROTON);
      setNeedsCrossSection(true);
    }
    
    //@}

    ///@name Analysis methods
    //@{

    ///Add Projections, Book histograms
    void init() {
      ZFinder zfinder(-1.7, 1.7, 15.0*GeV, MUON, 65.0*GeV, 115.0*GeV, 0.2);
      addProjection(zfinder, "ZFinder");
  
      _h_Z_pT_cross_section = bookHistogram1D(1, 1, 1);
    }

    // Do the analysis
    void analyze(const Event& e) {
      const double weight = e.weight();
      
      const ZFinder& zfinder = applyProjection<ZFinder>(e, "ZFinder");
      if (zfinder.particles().size()==1) {
     
        const FourMomentum Zmom = zfinder.particles()[0].momentum();
     
        // In Z pT
        _h_Z_pT_cross_section->fill(Zmom.pT(), weight);      

      }

    }


 /// Finalize
    void finalize() {
      const double invlumi = crossSection()/sumOfWeights();
      scale(_h_Z_pT_cross_section, invlumi);
    }
    //@}


  private:

    /// @name Histograms
    //@{
    AIDA::IHistogram1D * _h_Z_pT_cross_section;
    //@}



  };

  // This global object acts as a hook for the plugin system
  AnalysisBuilder<MUONANALYSIS> plugin_MUONANALYSIS;


}