#ifndef WGRAD_HISTMODULE_HH
#define WGRAD_HISTMODULE_HH

#include "FrameMods/HepHistModule.hh"
#include "Framework/APPModule.hh"

class HepHist1D;
// CLHEP random number classes :
class HepRandomEngine;
class RandGamma;
class RandGauss;

class WGRAD_HistModule : public HepHistModule
{
public:

  //-----------------------------------------------
  // Constructors
  //-----------------------------------------------

  WGRAD_HistModule( const char* const theName="WGRAD_HistModule", 
		    const char* const theDescription="WGRAD generator level histograms" );

  //-----------------------------------------------
  // Destructor
  //-----------------------------------------------

  virtual ~WGRAD_HistModule();
 
  // Operations    
  virtual AppResult            bookHistograms( void );
  virtual AppResult            fillHistograms( AbsEvent* anEvent );
  virtual AppModule*           clone( const char* cloneName );

  const char*  rcsId( ) const;

private:

  // Fitted Z pT distribution :
  double zpt(double x);
  // Weighting routines from Mark Lancaster to get to W pT :
  float zypt(float pt, float y, int iflag);
  float zwpt(float pt, float y, int iflag);
  // Recoil model to get U from the W pT :
  bool passCuts(double Wpx, double Wpy, double Mpx, double Mpy);

  // Array with original Z pT distribution once :
  double _Z_pt_orig[1000];
  // Reweighting array to go from Pythia W pT (default kT) -> "measured" W pT 
  // from 0 to 20 GeV in 0.5 GeV bins. Calculated by dividing _W_pt_resum by _W_pt.
  double _pythia_weights_ktdefault[40];

  // Histograms :
  HepHist1D* _W_pt;
  HepHist1D* _W_recoil;
  HepHist1D* _W_recoilReWeighted;
  HepHist1D* _W_tmass;
  HepHist1D* _Z_pt_fit;
  HepHist1D* _W_pt_resum;

  // CLHEP random number generating machinery :
  HepRandomEngine* _randomEngine;
  RandGamma* _gammaGenerator;
  RandGauss* _gaussGenerator;

  // Event properties after applying the recoil model :
  double _recoilModelRecoil;
  double _recoilModelT_Mass;
  double _recoilModelPtMiss;

};

#endif