/*
 *  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 FastJetFinder
 *
 *  Finds jets using FastJet library.
 *
 *  \author P. Demin - UCL, Louvain-la-Neuve
 *
 */

#include "modules/FastJetFinder.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>
#include <vector>

#include "fastjet/PseudoJet.hh"
#include "fastjet/JetDefinition.hh"
#include "fastjet/ClusterSequence.hh"
#include "fastjet/Selector.hh"
#include "fastjet/ClusterSequenceArea.hh"
#include "fastjet/tools/JetMedianBackgroundEstimator.hh"

#include "fastjet/plugins/SISCone/fastjet/SISConePlugin.hh"
#include "fastjet/plugins/CDFCones/fastjet/CDFMidPointPlugin.hh"
#include "fastjet/plugins/CDFCones/fastjet/CDFJetCluPlugin.hh"

#include "fastjet/contribs/Nsubjettiness/Nsubjettiness.hh"
#include "fastjet/contribs/Nsubjettiness/Njettiness.hh"
#include "fastjet/contribs/Nsubjettiness/NjettinessPlugin.hh"
#include "fastjet/contribs/Nsubjettiness/WinnerTakeAllRecombiner.hh"

#include "fastjet/tools/Filter.hh"
#include "fastjet/tools/Pruner.hh"
#include "fastjet/contribs/RecursiveTools/SoftDrop.hh"

using namespace std;
using namespace fastjet;
using namespace fastjet::contrib;


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

FastJetFinder::FastJetFinder() :
  fPlugin(0), fRecomb(0), fNjettinessPlugin(0), fDefinition(0), fAreaDefinition(0), fItInputArray(0)
{

}

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

FastJetFinder::~FastJetFinder()
{

}

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

void FastJetFinder::Init()
{
  JetDefinition::Plugin *plugin = 0;
  JetDefinition::Recombiner *recomb = 0;
  ExRootConfParam param;
  Long_t i, size;
  Double_t etaMin, etaMax;
  TEstimatorStruct estimatorStruct;

  // define algorithm

  fJetAlgorithm = GetInt("JetAlgorithm", 6);
  fParameterR = GetDouble("ParameterR", 0.5);

  fConeRadius = GetDouble("ConeRadius", 0.5);
  fSeedThreshold = GetDouble("SeedThreshold", 1.0);
  fConeAreaFraction = GetDouble("ConeAreaFraction", 1.0);
  fMaxIterations = GetInt("MaxIterations", 100);
  fMaxPairSize = GetInt("MaxPairSize", 2);
  fIratch = GetInt("Iratch", 1);
  fAdjacencyCut = GetInt("AdjacencyCut", 2);
  fOverlapThreshold = GetDouble("OverlapThreshold", 0.75);

  fJetPTMin = GetDouble("JetPTMin", 10.0);

  //-- N(sub)jettiness parameters --

  fComputeNsubjettiness = GetBool("ComputeNsubjettiness", false);
  fBeta = GetDouble("Beta", 1.0);
  fAxisMode = GetInt("AxisMode", 1);
  fRcutOff = GetDouble("RcutOff", 0.8); // used only if Njettiness is used as jet clustering algo (case 8)
  fN = GetInt("N", 2);                  // used only if Njettiness is used as jet clustering algo (case 8)

  //-- Trimming parameters --
  
  fComputeTrimming = GetBool("ComputeTrimming", false);
  fRTrim = GetDouble("RTrim", 0.2);
  fPtFracTrim = GetDouble("PtFracTrim", 0.05);
  

  //-- Pruning parameters --
  
  fComputePruning = GetBool("ComputePruning", false);
  fZcutPrun = GetDouble("ZcutPrun", 0.1);
  fRcutPrun = GetDouble("RcutPrun", 0.5);
  fRPrun = GetDouble("RPrun", 0.8);
 
  //-- SoftDrop parameters --
  
  fComputeSoftDrop     = GetBool("ComputeSoftDrop", false);
  fBetaSoftDrop        = GetDouble("BetaSoftDrop", 0.0);
  fSymmetryCutSoftDrop = GetDouble("SymmetryCutSoftDrop", 0.1);
  fR0SoftDrop= GetDouble("R0SoftDrop=", 0.8);
  

  // ---  Jet Area Parameters ---
  fAreaAlgorithm = GetInt("AreaAlgorithm", 0);
  fComputeRho = GetBool("ComputeRho", false);

  // - ghost based areas -
  fGhostEtaMax = GetDouble("GhostEtaMax", 5.0);
  fRepeat = GetInt("Repeat", 1);
  fGhostArea = GetDouble("GhostArea", 0.01);
  fGridScatter = GetDouble("GridScatter", 1.0);
  fPtScatter = GetDouble("PtScatter", 0.1);
  fMeanGhostPt = GetDouble("MeanGhostPt", 1.0E-100);

  // - voronoi based areas -
  fEffectiveRfact = GetDouble("EffectiveRfact", 1.0);

  switch(fAreaAlgorithm)
  {
    case 1:
      fAreaDefinition = new AreaDefinition(active_area_explicit_ghosts, GhostedAreaSpec(fGhostEtaMax, fRepeat, fGhostArea, fGridScatter, fPtScatter, fMeanGhostPt));
      break;
    case 2:
      fAreaDefinition = new AreaDefinition(one_ghost_passive_area, GhostedAreaSpec(fGhostEtaMax, fRepeat, fGhostArea, fGridScatter, fPtScatter, fMeanGhostPt));
      break;
    case 3:
      fAreaDefinition = new AreaDefinition(passive_area, GhostedAreaSpec(fGhostEtaMax, fRepeat, fGhostArea, fGridScatter, fPtScatter, fMeanGhostPt));
      break;
    case 4:
      fAreaDefinition = new AreaDefinition(VoronoiAreaSpec(fEffectiveRfact));
      break;
    case 5:
      fAreaDefinition = new AreaDefinition(active_area, GhostedAreaSpec(fGhostEtaMax, fRepeat, fGhostArea, fGridScatter, fPtScatter, fMeanGhostPt));
      break;
    default:
    case 0:
      fAreaDefinition = 0;
      break;
  }

  switch(fJetAlgorithm)
  {
    case 1:
      plugin = new CDFJetCluPlugin(fSeedThreshold, fConeRadius, fAdjacencyCut, fMaxIterations, fIratch, fOverlapThreshold);
      fDefinition = new JetDefinition(plugin);
      break;
    case 2:
      plugin = new CDFMidPointPlugin(fSeedThreshold, fConeRadius, fConeAreaFraction, fMaxPairSize, fMaxIterations, fOverlapThreshold);
      fDefinition = new JetDefinition(plugin);
      break;
    case 3:
      plugin = new SISConePlugin(fConeRadius, fOverlapThreshold, fMaxIterations, fJetPTMin);
      fDefinition = new JetDefinition(plugin);
      break;
    case 4:
      fDefinition = new JetDefinition(kt_algorithm, fParameterR);
      break;
    case 5:
      fDefinition = new JetDefinition(cambridge_algorithm, fParameterR);
      break;
    default:
    case 6:
      fDefinition = new JetDefinition(antikt_algorithm, fParameterR);
      break;
    case 7:
      recomb = new WinnerTakeAllRecombiner();
      fDefinition = new JetDefinition(antikt_algorithm, fParameterR, recomb, Best);
      break;
    case 8:
      fNjettinessPlugin = new NjettinessPlugin(fN, Njettiness::wta_kt_axes, Njettiness::unnormalized_cutoff_measure, fBeta, fRcutOff);
      fDefinition = new JetDefinition(fNjettinessPlugin);
      break;
  }

  fPlugin = plugin;
  fRecomb = recomb;

  ClusterSequence::print_banner();

  if(fComputeRho && fAreaDefinition)
  {
    // read eta ranges

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

    fEstimators.clear();
    for(i = 0; i < size/2; ++i)
    {
      etaMin = param[i*2].GetDouble();
      etaMax = param[i*2 + 1].GetDouble();
      estimatorStruct.estimator = new JetMedianBackgroundEstimator(SelectorEtaRange(etaMin, etaMax), *fDefinition, *fAreaDefinition);
      estimatorStruct.etaMin = etaMin;
      estimatorStruct.etaMax = etaMax;
      fEstimators.push_back(estimatorStruct);
    }
  }

  // import input array

  fInputArray = ImportArray(GetString("InputArray", "Calorimeter/towers"));
  fItInputArray = fInputArray->MakeIterator();

  // create output arrays

  fOutputArray = ExportArray(GetString("OutputArray", "jets"));
  fRhoOutputArray = ExportArray(GetString("RhoOutputArray", "rho"));
}

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

void FastJetFinder::Finish()
{
  vector< TEstimatorStruct >::iterator itEstimators;

  for(itEstimators = fEstimators.begin(); itEstimators != fEstimators.end(); ++itEstimators)
  {
    if(itEstimators->estimator) delete itEstimators->estimator;
  }

  if(fItInputArray) delete fItInputArray;
  if(fDefinition) delete fDefinition;
  if(fAreaDefinition) delete fAreaDefinition;
  if(fPlugin) delete static_cast<JetDefinition::Plugin*>(fPlugin);
  if(fRecomb) delete static_cast<JetDefinition::Recombiner*>(fRecomb);
  if(fNjettinessPlugin) delete static_cast<JetDefinition::Plugin*>(fNjettinessPlugin);
}

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

void FastJetFinder::Process()
{
  Candidate *candidate, *constituent;
  TLorentzVector momentum;

  Double_t deta, dphi, detaMax, dphiMax;
  Double_t time, timeWeight;
  Int_t number;
  Int_t charge; 
  Double_t rho = 0.0;
  PseudoJet jet, area;
  ClusterSequence *sequence;
  vector< PseudoJet > inputList, outputList, subjets;
  vector< PseudoJet >::iterator itInputList, itOutputList;
  vector< TEstimatorStruct >::iterator itEstimators;

  DelphesFactory *factory = GetFactory();

  inputList.clear();

  // loop over input objects
  fItInputArray->Reset();
  number = 0;
  while((candidate = static_cast<Candidate*>(fItInputArray->Next())))
  {
    momentum = candidate->Momentum;
    jet = PseudoJet(momentum.Px(), momentum.Py(), momentum.Pz(), momentum.E());
    jet.set_user_index(number);
    inputList.push_back(jet);
    ++number;
  }

  // construct jets
  if(fAreaDefinition)
  {
    sequence = new ClusterSequenceArea(inputList, *fDefinition, *fAreaDefinition);
  }
  else
  {
    sequence = new ClusterSequence(inputList, *fDefinition);
  }

  // compute rho and store it
  if(fComputeRho && fAreaDefinition)
  {
    for(itEstimators = fEstimators.begin(); itEstimators != fEstimators.end(); ++itEstimators)
    {
      itEstimators->estimator->set_particles(inputList);
      rho = itEstimators->estimator->rho();

      candidate = factory->NewCandidate();
      candidate->Momentum.SetPtEtaPhiE(rho, 0.0, 0.0, rho);
      candidate->Edges[0] = itEstimators->etaMin;
      candidate->Edges[1] = itEstimators->etaMax;
      fRhoOutputArray->Add(candidate);
    }
  }

  outputList.clear();
  outputList = sorted_by_pt(sequence->inclusive_jets(fJetPTMin));


  // loop over all jets and export them
  detaMax = 0.0;
  dphiMax = 0.0;
  for(itOutputList = outputList.begin(); itOutputList != outputList.end(); ++itOutputList)
  {
    jet = *itOutputList;
    if(fJetAlgorithm == 7) jet = join(jet.constituents());

    momentum.SetPxPyPzE(jet.px(), jet.py(), jet.pz(), jet.E());

    area.reset(0.0, 0.0, 0.0, 0.0);
    if(fAreaDefinition) area = itOutputList->area_4vector();

    candidate = factory->NewCandidate();

    time = 0.0;
    timeWeight = 0.0;

    charge = 0;

    inputList.clear();
    inputList = sequence->constituents(*itOutputList);

    for(itInputList = inputList.begin(); itInputList != inputList.end(); ++itInputList)
    {
      if(itInputList->user_index() < 0) continue;
      constituent = static_cast<Candidate*>(fInputArray->At(itInputList->user_index()));

      deta = TMath::Abs(momentum.Eta() - constituent->Momentum.Eta());
      dphi = TMath::Abs(momentum.DeltaPhi(constituent->Momentum));
      if(deta > detaMax) detaMax = deta;
      if(dphi > dphiMax) dphiMax = dphi;

      time += TMath::Sqrt(constituent->Momentum.E())*(constituent->Position.T());
      timeWeight += TMath::Sqrt(constituent->Momentum.E());

      charge += constituent->Charge;

      candidate->AddCandidate(constituent);
    }

    candidate->Momentum = momentum;
    candidate->Position.SetT(time/timeWeight);
    candidate->Area.SetPxPyPzE(area.px(), area.py(), area.pz(), area.E());

    candidate->DeltaEta = detaMax;
    candidate->DeltaPhi = dphiMax;
    candidate->Charge = charge; 
    //------------------------------------
    // Trimming
    //------------------------------------

     if(fComputeTrimming)
    {

      fastjet::Filter    trimmer(fastjet::JetDefinition(fastjet::kt_algorithm,fRTrim),fastjet::SelectorPtFractionMin(fPtFracTrim));
      fastjet::PseudoJet trimmed_jet = trimmer(*itOutputList);
      
      trimmed_jet = join(trimmed_jet.constituents());
     
      candidate->TrimmedP4[0].SetPtEtaPhiM(trimmed_jet.pt(), trimmed_jet.eta(), trimmed_jet.phi(), trimmed_jet.m());
        
      // four hardest subjets 
      subjets.clear();
      subjets = trimmed_jet.pieces();
      subjets = sorted_by_pt(subjets);
      
      candidate->NSubJetsTrimmed = subjets.size();

      for (size_t i = 0; i < subjets.size() and i < 4; i++){
	if(subjets.at(i).pt() < 0) continue ; 
 	candidate->TrimmedP4[i+1].SetPtEtaPhiM(subjets.at(i).pt(), subjets.at(i).eta(), subjets.at(i).phi(), subjets.at(i).m());
      }
    }
    
    
    //------------------------------------
    // Pruning
    //------------------------------------
    
    
    if(fComputePruning)
    {

      fastjet::Pruner    pruner(fastjet::JetDefinition(fastjet::cambridge_algorithm,fRPrun),fZcutPrun,fRcutPrun);
      fastjet::PseudoJet pruned_jet = pruner(*itOutputList);

      candidate->PrunedP4[0].SetPtEtaPhiM(pruned_jet.pt(), pruned_jet.eta(), pruned_jet.phi(), pruned_jet.m());
         
      // four hardest subjet 
      subjets.clear();
      subjets = pruned_jet.pieces();
      subjets = sorted_by_pt(subjets);
      
      candidate->NSubJetsPruned = subjets.size();

      for (size_t i = 0; i < subjets.size() and i < 4; i++){
	if(subjets.at(i).pt() < 0) continue ; 
  	candidate->PrunedP4[i+1].SetPtEtaPhiM(subjets.at(i).pt(), subjets.at(i).eta(), subjets.at(i).phi(), subjets.at(i).m());
      }

    } 
     
    //------------------------------------
    // SoftDrop
    //------------------------------------
   
    if(fComputeSoftDrop)
    {
    
      contrib::SoftDrop  softDrop(fBetaSoftDrop,fSymmetryCutSoftDrop,fR0SoftDrop);
      fastjet::PseudoJet softdrop_jet = softDrop(*itOutputList);
      
      candidate->SoftDroppedP4[0].SetPtEtaPhiM(softdrop_jet.pt(), softdrop_jet.eta(), softdrop_jet.phi(), softdrop_jet.m());
        
      // four hardest subjet 
      
      subjets.clear();
      subjets    = softdrop_jet.pieces();
      subjets    = sorted_by_pt(subjets);
      candidate->NSubJetsSoftDropped = softdrop_jet.pieces().size();

      for (size_t i = 0; i < subjets.size()  and i < 4; i++){
	if(subjets.at(i).pt() < 0) continue ; 
  	candidate->SoftDroppedP4[i+1].SetPtEtaPhiM(subjets.at(i).pt(), subjets.at(i).eta(), subjets.at(i).phi(), subjets.at(i).m());
      }
    }
  
    // --- compute N-subjettiness with N = 1,2,3,4,5 ----

    if(fComputeNsubjettiness)
    {
      Njettiness::AxesMode axisMode;

      switch(fAxisMode)
      {
        default:
        case 1:
          axisMode = Njettiness::wta_kt_axes;
          break;
        case 2:
          axisMode = Njettiness::onepass_wta_kt_axes;
          break;
        case 3:
          axisMode = Njettiness::kt_axes;
          break;
        case 4:
          axisMode = Njettiness::onepass_kt_axes;
          break;
      }

      Njettiness::MeasureMode measureMode = Njettiness::unnormalized_measure;

      Nsubjettiness nSub1(1, axisMode, measureMode, fBeta);
      Nsubjettiness nSub2(2, axisMode, measureMode, fBeta);
      Nsubjettiness nSub3(3, axisMode, measureMode, fBeta);
      Nsubjettiness nSub4(4, axisMode, measureMode, fBeta);
      Nsubjettiness nSub5(5, axisMode, measureMode, fBeta);

      candidate->Tau[0] = nSub1(*itOutputList);
      candidate->Tau[1] = nSub2(*itOutputList);
      candidate->Tau[2] = nSub3(*itOutputList);
      candidate->Tau[3] = nSub4(*itOutputList);
      candidate->Tau[4] = nSub5(*itOutputList);
    }

    fOutputArray->Add(candidate);
  }
  delete sequence;
}