/** \class Merger
 *
 *  Merges multiple input arrays into one output array
 *  and sums transverse momenta of all input objects.
 *
 *  $Date: 2013-02-09 17:32:10 +0000 (Sat, 09 Feb 2013) $
 *  $Revision: 894 $
 *
 *
 *  \author P. Demin - UCL, Louvain-la-Neuve
 *
 */

#include "modules/Merger.h"

#include "classes/DelphesClasses.h"
#include "classes/DelphesFactory.h"
#include "classes/DelphesFormula.h"

#include "ExRootAnalysis/ExRootResult.h"
#include "ExRootAnalysis/ExRootFilter.h"
#include "ExRootAnalysis/ExRootClassifier.h"

#include "TMath.h"
#include "TString.h"
#include "TFormula.h"
#include "TRandom3.h"
#include "TObjArray.h"
#include "TDatabasePDG.h"
#include "TLorentzVector.h"

#include <algorithm> 
#include <stdexcept>
#include <iostream>
#include <sstream>

using namespace std;

//------------------------------------------------------------------------------

Merger::Merger()
{
}

//------------------------------------------------------------------------------

Merger::~Merger()
{
}

//------------------------------------------------------------------------------

void Merger::Init()
{
  // import arrays with output from other modules

  ExRootConfParam param = GetParam("InputArray");
  Long_t i, size;
  const TObjArray *array;
  TIterator *iterator;

  size = param.GetSize();
  for(i = 0; i < size; ++i)
  {
    array = ImportArray(param[i].GetString());
    iterator = array->MakeIterator();

    fInputList.push_back(iterator);
  }

  // create output arrays

  fOutputArray = ExportArray(GetString("OutputArray", "candidates"));

  fMomentumOutputArray = ExportArray(GetString("MomentumOutputArray", "momentum"));
  
  fEnergyOutputArray = ExportArray(GetString("EnergyOutputArray", "energy"));
}

//------------------------------------------------------------------------------

void Merger::Finish()
{
  vector< TIterator * >::iterator itInputList;
  TIterator *iterator;

  for(itInputList = fInputList.begin(); itInputList != fInputList.end(); ++itInputList)
  {
    iterator = *itInputList;
    if(iterator) delete iterator;
  }
}

//------------------------------------------------------------------------------

void Merger::Process()
{
  Candidate *candidate;
  TLorentzVector momentum;
  Double_t sumPT, sumE;  
  vector< TIterator * >::iterator itInputList;
  TIterator *iterator;

  DelphesFactory *factory = GetFactory();
  
  momentum.SetPxPyPzE(0.0, 0.0, 0.0, 0.0);
  sumPT = 0;
  sumE = 0;

  // loop over all input arrays
  for(itInputList = fInputList.begin(); itInputList != fInputList.end(); ++itInputList)
  {
    iterator = *itInputList;

    // loop over all candidates
    iterator->Reset();
    while((candidate = static_cast<Candidate*>(iterator->Next())))
    {
      const TLorentzVector &candidateMomentum = candidate->Momentum;

      momentum += candidateMomentum;
      sumPT += candidateMomentum.Pt();
      sumE += candidateMomentum.E();

      fOutputArray->Add(candidate);
    }
  }

  candidate = factory->NewCandidate();
  
  candidate->Position.SetXYZT(0.0, 0.0, 0.0, 0.0);
  candidate->Momentum = momentum;
  
  fMomentumOutputArray->Add(candidate);

  candidate = factory->NewCandidate();
  
  candidate->Position.SetXYZT(0.0, 0.0, 0.0, 0.0);
  candidate->Momentum.SetPtEtaPhiE(sumPT, 0.0, 0.0, sumE);
  
  fEnergyOutputArray->Add(candidate);}

//------------------------------------------------------------------------------