/*
 *  Delphes: a framework for fast simulation of a generic collider experiment
 *  Copyright (C) 2012-2014  Universite catholique de Louvain (UCL), Belgium
 *
 *  This program is free software: you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation, either version 3 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

/** \class PdgCodeFilter
 *
 *  Removes particles with specific PDG codes
 *
 *  \author M. Selvaggi
 *
 */

#include "modules/PdgCodeFilter.h"

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

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

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

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

using namespace std;

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

PdgCodeFilter::PdgCodeFilter() :
  fItInputArray(0)
{
}

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

PdgCodeFilter::~PdgCodeFilter()
{
}

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

void PdgCodeFilter::Init()
{

  ExRootConfParam param;
  Size_t i, size;

  // PT threshold
  fPTMin = GetDouble("PTMin", 0.0);

  fInvert = GetBool("Invert", false);

  // no pileup
  fRequireNotPileup = GetBool("RequireNotPileup", false);

  fRequireStatus = GetBool("RequireStatus", false);
  fStatus = GetInt("Status", 1);

  fRequireCharge = GetBool("RequireCharge", false);
  fCharge = GetInt("Charge", 1);

  // keep bhadron
  fRequireKeepGhostBHadron = GetBool("RequireKeepGhostBHadron", false);

  // import input array
  fInputArray = ImportArray(GetString("InputArray", "Delphes/allParticles"));
  fItInputArray = fInputArray->MakeIterator();

  param = GetParam("PdgCode");
  size = param.GetSize();

  // read PdgCodes to be filtered out from the data card

  fPdgCodes.clear();
  for(i = 0; i < size; ++i)
  {
    fPdgCodes.push_back(param[i].GetInt());
  }

  // create output array
  fOutputArray = ExportArray(GetString("OutputArray", "filteredParticles"));
}

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

void PdgCodeFilter::Finish()
{
  if(fItInputArray) delete fItInputArray;
}

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

void PdgCodeFilter::Process()
{
  Candidate *candidate;
  Int_t pdgCode;
  Bool_t pass;
  Double_t pt;

  fItInputArray->Reset();
  while((candidate = static_cast<Candidate *>(fItInputArray->Next())))
  {
    pdgCode = candidate->PID;

    if (fRequireKeepGhostBHadron) {
      if (isBHadron(abs(pdgCode)) ){
        candidate->PT = candidate->PT * 1e-18;
        if (candidate->PT ==0) candidate->PT = 1e-18;
        candidate->Momentum.SetPtEtaPhiM(candidate->PT, candidate->Momentum.Eta(), candidate->Momentum.Phi(), candidate->Momentum.M());
        fOutputArray->Add(candidate);
        continue;
      }
    } 

    const TLorentzVector &candidateMomentum = candidate->Momentum;
    pt = candidateMomentum.Pt();

    if(pt < fPTMin) continue;
    if(fRequireStatus && (candidate->Status != fStatus)) continue;
    if(fRequireCharge && (candidate->Charge != fCharge)) continue;
    if(fRequireNotPileup && (candidate->IsPU > 0)) continue;

    pass = kTRUE;
    if(find(fPdgCodes.begin(), fPdgCodes.end(), pdgCode) != fPdgCodes.end()) pass = kFALSE;

    if(fInvert) pass = !pass;
    if(pass) fOutputArray->Add(candidate);
  }
}

Bool_t PdgCodeFilter::isBHadron(const unsigned int absPdgId) {
  if (absPdgId <= 100)
    return false;  // Fundamental particles and MC internals
  if (absPdgId >= 1000000000)
    return false;  // Nuclei, +-10LZZZAAAI

  // General form of PDG ID is 7 digit form
  // +- n nr nL nq1 nq2 nq3 nJ
  //const int nJ = absPdgId % 10; // Spin
  const int nq3 = (absPdgId / 10) % 10;
  const int nq2 = (absPdgId / 100) % 10;
  const int nq1 = (absPdgId / 1000) % 10;

  if (nq3 == 0)
    return false;  // Diquarks
  if (nq1 == 0 and nq2 == 5)
    return true;  // B mesons
  if (nq1 == 5)
    return true;  // B baryons

  return false;
}