/** \class Merger
 *
 *  Merges multiple input arrays into one output array
 *  and sums transverse momenta of all input objects.
 *
 *  $Date: 2012-11-18 15:57:08 +0100 (Sun, 18 Nov 2012) $
 *  $Revision: 814 $
 *
 *
 *  \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;
  DelphesFormula *formula;

  size = param.GetSize();
  for(i = 0; i < size/2; ++i)
  {
    array = ImportArray(param[i*2].GetString());
    iterator = array->MakeIterator();

    formula = new DelphesFormula;
    formula->Compile(param[i*2 + 1].GetString());

    fInputMap[iterator] = formula;
  }

  // create output arrays

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

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

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

void Merger::Finish()
{
  map< TIterator *, DelphesFormula * >::iterator itInputMap;
  TIterator *iterator;
  DelphesFormula *formula;

  for(itInputMap = fInputMap.begin(); itInputMap != fInputMap.end(); ++itInputMap)
  {
    iterator = itInputMap->first;
    formula = itInputMap->second;

    if(iterator) delete iterator;
    if(formula) delete formula;
  }
}

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

void Merger::Process()
{
  Candidate *candidate;
  TLorentzVector momentum;
  Double_t eta, pt;  
  map< TIterator *, DelphesFormula * >::iterator itInputMap;
  TIterator *iterator;
  DelphesFormula *formula;
  
  DelphesFactory *factory = GetFactory();
  
  momentum.SetPxPyPzE(0.0, 0.0, 0.0, 0.0);

  // loop over all input arrays
  for(itInputMap = fInputMap.begin(); itInputMap != fInputMap.end(); ++itInputMap)
  {
    iterator = itInputMap->first;
    formula = itInputMap->second;

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

      eta = candidatePosition.Eta();
      pt = candidateMomentum.Pt();

      if(formula->Eval(pt, eta))
      {
        momentum += candidateMomentum;
        fOutputArray->Add(candidate);
      }
    }
  }

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

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