//--------------------------------------------------------------------------
// ParmExample: Example analysis module for the Offline Workbook.
// A module with 4 run-time parameters.
// The workbook can be found on the web at:
//   http://www.slac.stanford.edu/BFROOT/www/doc/workbook/workbook.html
//------------------------------------------------------------------------

#include "BaBar/BaBar.hh"

#include "BetaMiniUser/ParmExample.hh"

#include "AbsEnv/AbsEnv.hh"
#include "Beta/BtaCandidate.hh"
#include "GenEnv/GenEnv.hh"
#include "HepTuple/TupleManager.h"
#include "CLHEP/Alist/AIterator.h"

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

// in general, a module constructor should not do much.  The beginJob
// function is a better place to put initialization

ParmExample::ParmExample( const char* const theName, 
		  const char* const theDescription )
  : AppModule( theName, theDescription ),
    _nbins("nbins",this,25),
    _pMin("pMin",this, 0.),
    _pMax("pMax",this, 1.0),
    _trackList("trackList", this, "ChargedTracks")
{
  commands()->append( & _nbins );
  commands()->append( & _pMin );
  commands()->append( & _pMax );
  commands()->append( & _trackList );
}

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

// The destructor should be limited to undoing the work of the constructor

ParmExample::~ParmExample( )
{
}


//--------------
// Operations --
//--------------

// The beginJob member function is run before any events are
// processed.  In this example code, it opens the output histogram file
// and then books a histogram.

AppResult
ParmExample::beginJob( AbsEvent* anEvent )
{
      
  HepTupleManager* manager = gblEnv->getGen()->ntupleManager();

  // book the number-of-tracks histogram
  _numTrkHisto = manager->histogram("nTrack",  20, 0., 20. ); 
  _pHisto = manager->histogram("pTrack", _nbins.value() , _pMin.value(), _pMax.value() );

  return AppResult::OK;
}

// The endJob function is called after all events have been processed.

AppResult
ParmExample::endJob( AbsEvent* anEvent ) 
{
  return AppResult::OK;
}

// event function is called once per event


AppResult
ParmExample::event( AbsEvent* anEvent )
  {  

  // get list of input track candidates
  HepAList<BtaCandidate>* trkList  =
    Ifd<HepAList< BtaCandidate > >::get(anEvent, _trackList.value());

  //histogram number of tracks in event
  _numTrkHisto->accumulate( trkList->length() );

  // Loop over track candidates to plot momentum 
   HepAListIterator<BtaCandidate> iterTrk(*trkList);
   BtaCandidate* trk(0);
   while ( trk = iterTrk()) {
    _pHisto->accumulate( trk->p() );
   }
  
  // done
  return AppResult::OK;
}