/* $Id$ */

#include "AliMultiplicityMCSelector.h"

#include <TStyle.h>
#include <TSystem.h>
#include <TCanvas.h>
#include <TVector3.h>
#include <TChain.h>
#include <TFile.h>
#include <TH2F.h>
#include <TH3F.h>
#include <TParticle.h>
#include <TRandom.h>
#include <TNtuple.h>

#include <AliLog.h>
#include <AliESD.h>
#include <AliStack.h>
#include <AliHeader.h>
#include <AliGenEventHeader.h>
#include <AliMultiplicity.h>

#include "esdTrackCuts/AliESDtrackCuts.h"
#include "AliPWG0Helper.h"
#include "AliPWG0depHelper.h"
#include "dNdEta/AliMultiplicityCorrection.h"
#include "AliCorrection.h"
#include "AliCorrectionMatrix3D.h"

//#define TPCMEASUREMENT
#define ITSMEASUREMENT

ClassImp(AliMultiplicityMCSelector)

AliMultiplicityMCSelector::AliMultiplicityMCSelector() :
  AliSelectorRL(),
  fMultiplicity(0),
  fEsdTrackCuts(0),
  fSystSkipParticles(kFALSE),
  fSelectProcessType(0),
  fParticleSpecies(0)
{
  //
  // Constructor. Initialization of pointers
  //

  for (Int_t i = 0; i<4; i++)
    fParticleCorrection[i] = 0;
}

AliMultiplicityMCSelector::~AliMultiplicityMCSelector()
{
  //
  // Destructor
  //

  // histograms are in the output list and deleted when the output
  // list is deleted by the TSelector dtor
}

void AliMultiplicityMCSelector::Begin(TTree* tree)
{
  // Begin function

  AliSelectorRL::Begin(tree);

  ReadUserObjects(tree);
}

void AliMultiplicityMCSelector::ReadUserObjects(TTree* tree)
{
  // read the user objects, called from slavebegin and begin

  if (!fEsdTrackCuts && fInput)
    fEsdTrackCuts = dynamic_cast<AliESDtrackCuts*> (fInput->FindObject("AliESDtrackCuts"));

  if (!fEsdTrackCuts && tree)
    fEsdTrackCuts = dynamic_cast<AliESDtrackCuts*> (tree->GetUserInfo()->FindObject("AliESDtrackCuts"));

  if (!fEsdTrackCuts)
     AliDebug(AliLog::kError, "ERROR: Could not read EsdTrackCuts from input list.");
}

void AliMultiplicityMCSelector::SlaveBegin(TTree* tree)
{
  // The SlaveBegin() function is called after the Begin() function.
  // When running with PROOF SlaveBegin() is called on each slave server.
  // The tree argument is deprecated (on PROOF 0 is passed).

  AliSelector::SlaveBegin(tree);

  ReadUserObjects(tree);

  fMultiplicity = new AliMultiplicityCorrection("Multiplicity", "Multiplicity");

  TString option(GetOption());
  if (option.Contains("skip-particles"))
  {
    fSystSkipParticles = kTRUE;
    AliInfo("WARNING: Systematic study enabled. Particles will be skipped.");
  }

  if (option.Contains("particle-efficiency"))
    for (Int_t i = 0; i<4; i++)
      fParticleCorrection[i] = new AliCorrection(Form("correction_%d", i), Form("correction_%d", i));

  if (option.Contains("only-process-type-nd"))
    fSelectProcessType = 1;

  if (option.Contains("only-process-type-sd"))
    fSelectProcessType = 2;

  if (option.Contains("only-process-type-dd"))
    fSelectProcessType = 3;

  if (fSelectProcessType != 0)
    AliInfo(Form("WARNING: Systematic study enabled. Only considering process type %d", fSelectProcessType));

  if (option.Contains("particle-species"))
    fParticleSpecies = new TNtuple("fParticleSpecies", "fParticleSpecies", "Pi_True:K_True:p_True:o_True:Pi_Rec:K_Rec:p_Rec:o_Rec");
}

void AliMultiplicityMCSelector::Init(TTree* tree)
{
  // read the user objects

  AliSelectorRL::Init(tree);

  // enable only the needed branches
  if (tree)
  {
    tree->SetBranchStatus("*", 0);
    tree->SetBranchStatus("fTriggerMask", 1);
    tree->SetBranchStatus("fSPDVertex*", 1);

    #ifdef ITSMEASUREMENT
      tree->SetBranchStatus("fSPDMult*", 1);
    #endif

    #ifdef TPCMEASUREMENT
      AliESDtrackCuts::EnableNeededBranches(tree);
    #endif
  }
}

Bool_t AliMultiplicityMCSelector::Process(Long64_t entry)
{
  // The Process() function is called for each entry in the tree (or possibly
  // keyed object in the case of PROOF) to be processed. The entry argument
  // specifies which entry in the currently loaded tree is to be processed.
  // It can be passed to either TTree::GetEntry() or TBranch::GetEntry()
  // to read either all or the required parts of the data. When processing
  // keyed objects with PROOF, the object is already loaded and is available
  // via the fObject pointer.
  //
  // This function should contain the "body" of the analysis. It can contain
  // simple or elaborate selection criteria, run algorithms on the data
  // of the event and typically fill histograms.

  // WARNING when a selector is used with a TChain, you must use
  //  the pointer to the current TTree to call GetEntry(entry).
  //  The entry is always the local entry number in the current tree.
  //  Assuming that fTree is the pointer to the TChain being processed,
  //  use fTree->GetTree()->GetEntry(entry).

  if (AliSelectorRL::Process(entry) == kFALSE)
    return kFALSE;

  // Check prerequisites
  if (!fESD)
  {
    AliDebug(AliLog::kError, "ESD branch not available");
    return kFALSE;
  }

  if (!fEsdTrackCuts)
  {
    AliDebug(AliLog::kError, "fESDTrackCuts not available");
    return kFALSE;
  }

  AliHeader* header = GetHeader();
  if (!header)
  {
    AliDebug(AliLog::kError, "Header not available");
    return kFALSE;
  }

  AliStack* stack = GetStack();
  if (!stack)
  {
    AliDebug(AliLog::kError, "Stack not available");
    return kFALSE;
  }

  if (fSelectProcessType > 0)
  {
    // getting process information; NB: this only works for Pythia
    Int_t processtype = AliPWG0depHelper::GetPythiaEventProcessType(header);

    Bool_t processEvent = kFALSE;

    // non diffractive
    if (fSelectProcessType == 1 && processtype !=92 && processtype !=93 && processtype != 94)
      processEvent = kTRUE;

    // single diffractive
    if (fSelectProcessType == 2 && (processtype == 92 || processtype == 93))
      processEvent = kTRUE;

    // double diffractive
    if (fSelectProcessType == 3 && processtype == 94)
      processEvent = kTRUE;

    if (!processEvent)
    {
      AliDebug(AliLog::kDebug, Form("Skipping this event, because it is not of the requested process type (%d)", processtype));
      return kTRUE;
    }
  }

  Bool_t eventTriggered = AliPWG0Helper::IsEventTriggered(fESD);
  eventTriggered = kTRUE; // no generated trigger for the simulated events
  Bool_t eventVertex = AliPWG0Helper::IsVertexReconstructed(fESD);

  // get the ESD vertex
  const AliESDVertex* vtxESD = fESD->GetVertex();
  Double_t vtx[3];
  vtxESD->GetXYZ(vtx);

  // get the MC vertex
  AliGenEventHeader* genHeader = header->GenEventHeader();
  TArrayF vtxMC(3);
  genHeader->PrimaryVertex(vtxMC);

  // get tracklets
  const AliMultiplicity* mult = fESD->GetMultiplicity();
  if (!mult)
  {
    AliDebug(AliLog::kError, "AliMultiplicity not available");
    return kFALSE;
  }

  //const Float_t kPtCut = 0.3;

  // get number of tracks from MC
  // loop over mc particles
  Int_t nPrim  = stack->GetNprimary();

  // tracks in different eta ranges
  Int_t nMCTracks05 = 0;
  Int_t nMCTracks10 = 0;
  Int_t nMCTracks15 = 0;
  Int_t nMCTracks20 = 0;
  Int_t nMCTracksAll = 0;

  // tracks per particle species, in |eta| < 2 (systematic study)
  Int_t nMCTracksSpecies[4]; // (pi, K, p, other)
  for (Int_t i = 0; i<4; ++i)
    nMCTracksSpecies[i] = 0;

  for (Int_t iMc = 0; iMc < nPrim; ++iMc)
  {
    AliDebug(AliLog::kDebug+1, Form("MC Loop: Processing particle %d.", iMc));

    TParticle* particle = stack->Particle(iMc);

    if (!particle)
    {
      AliDebug(AliLog::kError, Form("UNEXPECTED: particle with label %d not found in stack (mc loop).", iMc));
      continue;
    }

    Bool_t debug = kFALSE;
    if (AliPWG0Helper::IsPrimaryCharged(particle, nPrim, debug) == kFALSE)
    {
      //printf("%d) DROPPED ", iMC);
      //particle->Print();
      continue;
    }

    //printf("%d) OK      ", iMC);
    //particle->Print();

    //if (particle->Pt() < kPtCut)
    //  continue;

    if (TMath::Abs(particle->Eta()) < 0.5)
      nMCTracks05++;

    if (TMath::Abs(particle->Eta()) < 1.0)
      nMCTracks10++;

    if (TMath::Abs(particle->Eta()) < 1.5)
      nMCTracks15++;

    if (TMath::Abs(particle->Eta()) < 2.0)
      nMCTracks20++;

    nMCTracksAll++;

    Int_t id = -1;
    switch (TMath::Abs(particle->GetPdgCode()))
    {
      case 211: id = 0; break;
      case 321: id = 1; break;
      case 2212: id = 2; break;
      default: id = 3; break;
    }
    if (TMath::Abs(particle->Eta()) < 2.0)
      nMCTracksSpecies[id]++;
    if (fParticleCorrection[id])
      fParticleCorrection[id]->GetTrackCorrection()->FillGene(vtxMC[2], particle->Eta(), particle->Pt());
  }// end of mc particle

  fMultiplicity->FillGenerated(vtxMC[2], eventTriggered, eventVertex, nMCTracks05, nMCTracks10, nMCTracks15, nMCTracks20, nMCTracksAll);

  if (!eventTriggered || !eventVertex)
    return kTRUE;

  Int_t nESDTracks05 = 0;
  Int_t nESDTracks10 = 0;
  Int_t nESDTracks15 = 0;
  Int_t nESDTracks20 = 0;

  // tracks per particle species, in |eta| < 2 (systematic study)
  Int_t nESDTracksSpecies[4]; // (pi, K, p, other)
  for (Int_t i = 0; i<4; ++i)
    nESDTracksSpecies[i] = 0;

#ifdef ITSMEASUREMENT
  // get multiplicity from ITS tracklets
  for (Int_t i=0; i<mult->GetNumberOfTracklets(); ++i)
  {
    //printf("%d %f %f %f\n", i, mult->GetTheta(i), mult->GetPhi(i), mult->GetDeltaPhi(i));

    // this removes non-tracklets. Very bad solution. SPD guys are working on better solution...
    if (mult->GetDeltaPhi(i) < -1000)
      continue;

    // systematic study: 10% lower efficiency
    if (fSystSkipParticles && gRandom->Uniform() < 0.1)
      continue;

    Float_t theta = mult->GetTheta(i);
    Float_t eta   = -TMath::Log(TMath::Tan(theta/2.));

    if (TMath::Abs(eta) < 0.5)
      nESDTracks05++;

    if (TMath::Abs(eta) < 1.0)
      nESDTracks10++;

    if (TMath::Abs(eta) < 1.5)
      nESDTracks15++;

    if (TMath::Abs(eta) < 2.0)
      nESDTracks20++;

    // TODO define needed, because this only works with new AliRoot
    Int_t label = mult->GetLabel(i);
    if (label < 0)
      continue;

    TParticle* mother = AliPWG0depHelper::FindPrimaryMother(stack, label);

    if (!mother)
      continue;

    Int_t id = -1;
    switch (TMath::Abs(mother->GetPdgCode()))
    {
      case 211: id = 0; break;
      case 321: id = 1; break;
      case 2212: id = 2; break;
      default: id = 3; break;
    }
    if (TMath::Abs(eta) < 2.0)
      nESDTracksSpecies[id]++;
    if (fParticleCorrection[id])
      fParticleCorrection[id]->GetTrackCorrection()->FillMeas(vtxMC[2], mother->Eta(), mother->Pt());
  }
#endif

#ifdef TPCMEASUREMENT
  // get multiplicity from ESD tracks
  TObjArray* list = fEsdTrackCuts->GetAcceptedTracks(fESD);
  Int_t nGoodTracks = list->GetEntries();
  // loop over esd tracks
  for (Int_t i=0; i<nGoodTracks; i++)
  {
    AliESDtrack* esdTrack = dynamic_cast<AliESDtrack*> (list->At(i));
    if (!esdTrack)
    {
      AliDebug(AliLog::kError, Form("ERROR: Could not retrieve track %d.", i));
      continue;
    }

    Double_t p[3];
    esdTrack->GetConstrainedPxPyPz(p); // ### TODO should be okay because we have a vertex, however GetInnerPxPyPy / GetOuterPxPyPy also exist
    TVector3 vector(p);

    Float_t theta = vector.Theta();
    Float_t eta   = -TMath::Log(TMath::Tan(theta/2.));
    Float_t pt = vector.Pt();

    //if (pt < kPtCut)
    //  continue;

    if (TMath::Abs(eta) < 0.5)
      nESDTracks05++;

    if (TMath::Abs(eta) < 1.0)
      nESDTracks10++;

    if (TMath::Abs(eta) < 1.5)
      nESDTracks15++;

    if (TMath::Abs(eta) < 2.0)
      nESDTracks20++;

    Int_t label = esdTrack->GetLabel();
    if (label < 0)
      continue;

    TParticle* mother = AliPWG0depHelper::FindPrimaryMother(stack, label);

    if (!mother)
      continue;

    Int_t id = -1;
    switch (TMath::Abs(mother->GetPdgCode()))
    {
      case 211: id = 0; break;
      case 321: id = 1; break;
      case 2212: id = 2; break;
      default: id = 3; break;
    }
    if (TMath::Abs(eta) < 2.0)
      nESDTracksSpecies[id]++;
    if (fParticleCorrection[id])
      fParticleCorrection[id]->GetTrackCorrection()->FillMeas(vtxMC[2], mother->Eta(), mother->Pt());
  }
#endif

  if (nMCTracks20 == 0 && nESDTracks20 > 3)
    printf("WARNING: Event %lld has %d generated and %d reconstructed...\n", entry, nMCTracks05, nESDTracks05);

  fMultiplicity->FillMeasured(vtx[2], nESDTracks05, nESDTracks10, nESDTracks15, nESDTracks20);

  // TODO should this be vtx[2] or vtxMC[2] ?
  fMultiplicity->FillCorrection(vtxMC[2], nMCTracks05, nMCTracks10, nMCTracks15, nMCTracks20, nMCTracksAll, nESDTracks05, nESDTracks10, nESDTracks15, nESDTracks20);

  if (fParticleSpecies)
    fParticleSpecies->Fill(nMCTracksSpecies[0], nMCTracksSpecies[1], nMCTracksSpecies[2], nMCTracksSpecies[3], nESDTracksSpecies[0], nESDTracksSpecies[1], nESDTracksSpecies[2], nESDTracksSpecies[3]);

  return kTRUE;
}

void AliMultiplicityMCSelector::SlaveTerminate()
{
  // The SlaveTerminate() function is called after all entries or objects
  // have been processed. When running with PROOF SlaveTerminate() is called
  // on each slave server.

  AliSelector::SlaveTerminate();

  // Add the histograms to the output on each slave server
  if (!fOutput)
  {
    AliDebug(AliLog::kError, Form("ERROR: Output list not initialized."));
    return;
  }

  fOutput->Add(fMultiplicity);
  for (Int_t i = 0; i < 4; ++i)
    fOutput->Add(fParticleCorrection[i]);

  fOutput->Add(fParticleSpecies);
}

void AliMultiplicityMCSelector::Terminate()
{
  // The Terminate() function is the last function to be called during
  // a query. It always runs on the client, it can be used to present
  // the results graphically or save the results to file.

  AliSelector::Terminate();

  fMultiplicity = dynamic_cast<AliMultiplicityCorrection*> (fOutput->FindObject("Multiplicity"));
  for (Int_t i = 0; i < 4; ++i)
    fParticleCorrection[i] = dynamic_cast<AliCorrection*> (fOutput->FindObject(Form("correction_%d", i)));
  fParticleSpecies = dynamic_cast<TNtuple*> (fOutput->FindObject("fParticleSpecies"));

  if (!fMultiplicity)
  {
    AliDebug(AliLog::kError, Form("ERROR: Histograms not available %p", (void*) fMultiplicity));
    return;
  }

  TFile* file = TFile::Open("multiplicityMC.root", "RECREATE");

  fMultiplicity->SaveHistograms();
  for (Int_t i = 0; i < 4; ++i)
    if (fParticleCorrection[i])
      fParticleCorrection[i]->SaveHistograms();
  fParticleSpecies->Write();

  file->Close();

  fMultiplicity->DrawHistograms();
}