/**************************************************************************
 * Copyright(c) 1998-1999, ALICE Experiment at CERN, All rights reserved. *
 *                                                                        *
 * Author: The ALICE Off-line Project.                                    *
 * Contributors are mentioned in the code where appropriate.              *
 *                                                                        *
 * Permission to use, copy, modify and distribute this software and its   *
 * documentation strictly for non-commercial purposes is hereby granted   *
 * without fee, provided that the above copyright notice appears in all   *
 * copies and that both the copyright notice and this permission notice   *
 * appear in the supporting documentation. The authors make no claims     *
 * about the suitability of this software for any purpose. It is          *
 * provided "as is" without express or implied warranty.                  *
 **************************************************************************/

/* $Id$ */


// Generator using Herwig as an external generator
// The main Herwig options are accessable for the user through this interface.
// Uses the THerwig implementation of TGenerator.


#include <Riostream.h>
#include <TClonesArray.h>
#include <TParticle.h>

#include <THerwig6.h>

#include "AliGenHerwig.h"
#include "AliGenHerwigEventHeader.h"
#include "AliHerwigRndm.h"
#include "AliMC.h"
#include "AliRun.h"
#include "driver.h"

using std::cerr;
using std::endl;

ClassImp(AliGenHerwig)


  AliGenHerwig::AliGenHerwig() :
    AliGenMC(),
    fAutPDF("LHAPDF"),
    fModPDF(19070),
    fStrucFunc(kCTEQ5L),
    fKeep(0),
    fDecaysOff(1),
    fTrigger(0),
    fSelectAll(0),
    fFlavor(0),
    fMomentum1(7000),
    fMomentum2(7000),
    fKineBias(1),
    fTrials(0),
    fXsection(0),
    fHerwig(0x0),
    fProcess(0),
    fPtHardMin(0.),
    fPtHardMax(9999.),
    fPtRMS(0.),
    fMaxPr(10),
    fMaxErrors(1000),
    fEnSoft(1),
    fEv1Pr(0),
    fEv2Pr(0),
    fFileName(0),
    fEtaMinParton(-20.),     
    fEtaMaxParton(20.),     
    fPhiMinParton(0.),     
    fPhiMaxParton(2.* TMath::Pi()),     
    fEtaMinGamma(-20.),      
    fEtaMaxGamma(20.),      
    fPhiMinGamma(0.),      
    fPhiMaxGamma(2. * TMath::Pi()),
    fHeader(0)
{
// Constructor
  fEnergyCMS = 14000;
}

AliGenHerwig::AliGenHerwig(Int_t npart)
    :AliGenMC(npart),
    fAutPDF("LHAPDF"),
    fModPDF(19070),
    fStrucFunc(kCTEQ5L),
    fKeep(0),
    fDecaysOff(1),
    fTrigger(0),
    fSelectAll(0),
    fFlavor(0),
    fMomentum1(7000),
    fMomentum2(7000),
    fKineBias(1),
    fTrials(0),
    fXsection(0),
    fHerwig(0x0),
    fProcess(0),
    fPtHardMin(0.),
    fPtHardMax(9999.),
    fPtRMS(0.),
    fMaxPr(10),
    fMaxErrors(1000),
    fEnSoft(1),
    fEv1Pr(0),
    fEv2Pr(0),
    fFileName(0),
    fEtaMinParton(-20.),     
    fEtaMaxParton(20.),     
    fPhiMinParton(0.),     
    fPhiMaxParton(2.* TMath::Pi()),     
    fEtaMinGamma(-20.),      
    fEtaMaxGamma(20.),      
    fPhiMinGamma(0.),
    fPhiMaxGamma(2. * TMath::Pi()),
    fHeader(0)
{
// Constructor
    fEnergyCMS = 14000;
    SetTarget();
    SetProjectile();
    // Set random number generator
    AliHerwigRndm::SetHerwigRandom(GetRandom());
}

AliGenHerwig::~AliGenHerwig()
{
// Destructor
}

void AliGenHerwig::SetEventListRange(Int_t eventFirst, Int_t eventLast)
{
  fEv1Pr = eventFirst;
  fEv2Pr = eventLast;
  if ( fEv2Pr == -1 ) fEv2Pr = fEv1Pr;
}

void AliGenHerwig::Init()
{
// Initialisation
  fTarget.Resize(8);
  fProjectile.Resize(8);
  SetMC(new THerwig6());
  fHerwig=(THerwig6*) fMCEvGen;
  // initialize common blocks
  fHerwig->Initialize(fProjectile.Data(), fTarget.Data(), fMomentum1, fMomentum2, fProcess); // 
  // reset parameters according to user needs
  InitPDF();
  fHerwig->SetPTMIN(fPtHardMin);
  fHerwig->SetPTMAX(fPtHardMax);
  fHerwig->SetPTRMS(fPtRMS);
  fHerwig->SetMAXPR(fMaxPr);
  fHerwig->SetMAXER(fMaxErrors);
  fHerwig->SetENSOF(fEnSoft);
// C---D,U,S,C,B,T QUARK AND GLUON MASSES (IN THAT ORDER)
//       RMASS(1)=0.32
//       RMASS(2)=0.32
//       RMASS(3)=0.5
//       RMASS(4)=1.55
//       RMASS(5)=4.75
//       RMASS(6)=174.3
//       RMASS(13)=0.75

  fHerwig->SetRMASS(4,1.2);
  fHerwig->SetRMASS(5,4.75);

  if ( fProcess < 0 ) strncpy(VVJIN.QQIN,fFileName.Data(), 49);

  //fHerwig->Hwusta("PI0     ");

  // compute parameter dependent constants
  fHerwig->PrepareRun();
}

void AliGenHerwig::InitJimmy()
{
// Initialisation
  fTarget.Resize(8);
  fProjectile.Resize(8);
  SetMC(new THerwig6());
  fHerwig=(THerwig6*) fMCEvGen;
  // initialize common blocks
  fHerwig->InitializeJimmy(fProjectile, fTarget, fMomentum1, fMomentum2, fProcess);
  // reset parameters according to user needs
  InitPDF();
  fHerwig->SetPTMIN(fPtHardMin);
  fHerwig->SetPTRMS(fPtRMS);
  fHerwig->SetMAXPR(fMaxPr);
  fHerwig->SetMAXER(fMaxErrors);
  fHerwig->SetENSOF(fEnSoft);

// C---D,U,S,C,B,T QUARK AND GLUON MASSES (IN THAT ORDER)
//       RMASS(1)=0.32
//       RMASS(2)=0.32
//       RMASS(3)=0.5
//       RMASS(4)=1.55
//       RMASS(5)=4.75
//       RMASS(6)=174.3
//       RMASS(13)=0.75

  fHerwig->SetRMASS(4,1.2);
  fHerwig->SetRMASS(5,4.75);

  if ( fProcess < 0 ) strncpy(VVJIN.QQIN,fFileName.Data(), 49);

  //  fHerwig->Hwusta("PI0     ");

  // compute parameter dependent constants
  fHerwig->PrepareRunJimmy();
}

void AliGenHerwig::InitPDF()
{
// Initialize PDF
  switch(fStrucFunc)
    {
// ONLY USES LHAPDF STRUCTURE FUNCTIONS
    case kGRVLO98:
      fModPDF=80060;
      fAutPDF="HWLHAPDF";
      break;
    case kCTEQ6:
      fModPDF=10040;
      fAutPDF="HWLHAPDF";
      break;
    case kCTEQ61:
      fModPDF=10100;
      fAutPDF="HWLHAPDF";
      break;
    case kCTEQ6m:
      fModPDF=10050;
      fAutPDF="HWLHAPDF";
      break;
    case kCTEQ6l:
      fModPDF=10041;
      fAutPDF="HWLHAPDF";
      break;
    case kCTEQ6ll:
      fModPDF=10042;
      fAutPDF="HWLHAPDF";
      break;
    case kCTEQ5M:
      fModPDF=19050;
      fAutPDF="HWLHAPDF";
      break;
    case kCTEQ5L:
      fModPDF=19070;
      fAutPDF="HWLHAPDF";
      break;
    case kCTEQ4M:
      fModPDF=19150;
      fAutPDF="HWLHAPDF";
      break;
    case kCTEQ4L:
      fModPDF=19170;
      fAutPDF="HWLHAPDF";
      break;
//    case kMRST2004nlo:
//      fModPDF=20400;
//      fAutPDF="HWLHAPDF";
//      break;
    default:
      cerr << "This structure function is not inplemented " << fStrucFunc << endl;
      break;
    }
  fAutPDF.Resize(20);
  fHerwig->SetMODPDF(1,fModPDF);
  fHerwig->SetMODPDF(2,fModPDF);
  fHerwig->SetAUTPDF(1,fAutPDF);
  fHerwig->SetAUTPDF(2,fAutPDF);
}

void AliGenHerwig::Generate()
{
  // Generate one event

  Float_t polar[3]  =   {0,0,0};
  Float_t origin[3] =   {0,0,0};
  Float_t p[4];

  static TClonesArray *particles;
  //  converts from mm/c to s
  const Float_t kconv=0.001/2.999792458e8;
  //
  Int_t nt=0;
  Int_t jev=0;
  Int_t kf, ks, imo;
  kf=0;

  if(!particles) particles=new TClonesArray("TParticle",10000);

  fTrials=0;

  //  Set collision vertex position 
  if (fVertexSmear == kPerEvent) Vertex();

  while(1)
    {
	fHerwig->GenerateEvent();
	fTrials++;
	fHerwig->ImportParticles(particles,"All");
	Int_t np = particles->GetEntriesFast()-1;
	if (np == 0 ) continue;

	//Check hard partons or direct gamma in kine range

	if (fProcess == kHeJets || fProcess == kHeDirectGamma) {
	    TParticle* parton1 = (TParticle *) particles->At(6);
	    TParticle* parton2 = (TParticle *) particles->At(7);
	    if (!CheckParton(parton1, parton2))  continue ;
	} 

	// 
	if (gAlice) {
	    if (gAlice->GetEvNumber()>=fEv1Pr &&
		gAlice->GetEvNumber()<=fEv2Pr) fHerwig->PrintEvt();

	}

	
	Int_t nc = 0;
	fNprimaries = 0;
	
	Int_t * newPos = new Int_t[np];
	for (Int_t i = 0; i<np; i++) *(newPos+i)=-1;

	for (Int_t i = 0; i<np; i++) {
	    TParticle *  iparticle       = (TParticle *) particles->At(i);
	    imo = iparticle->GetFirstMother();
	    kf        = iparticle->GetPdgCode();
	    ks        = iparticle->GetStatusCode();
	    if (ks != 3 &&
		KinematicSelection(iparticle,0))
	    {
		nc++;
		p[0]=iparticle->Px();
		p[1]=iparticle->Py();
		p[2]=iparticle->Pz();
		p[3]=iparticle->Energy();

		origin[0] = fVertex[0] + iparticle->Vx()/10; // [cm]
		origin[1] = fVertex[1] + iparticle->Vy()/10; // [cm]
		origin[2] = fVertex[2] + iparticle->Vz()/10; // [cm]

		Float_t tof = fTime + kconv*iparticle->T();
		Int_t   iparent = (imo > -1) ? newPos[imo] : -1;
		Int_t   trackIt = (ks == 1) && fTrackIt;
		PushTrack(trackIt, iparent, kf,
			  p[0], p[1], p[2], p[3],
			  origin[0], origin[1], origin[2],
			  tof,
			  polar[0], polar[1], polar[2],
			  kPPrimary, nt, fHerwig->GetEVWGT(), ks);
		KeepTrack(nt);
		newPos[i]=nt;
		fNprimaries++;
	    } // end of if: selection of particle
	} // end of for: particle loop
	if (newPos) delete[] newPos;
	if (nc > 0) {
	    jev+=nc;
	    if (jev >= fNpart || fNpart == -1) {
		fKineBias=Float_t(fNpart)/Float_t(fTrials);
		break;
	    }
	}
    }
//
  MakeHeader();
//  
  SetHighWaterMark(nt);
//  adjust weight due to kinematic selection
  AdjustWeights();
//  get cross-section
  fXsection=fHerwig->GetAVWGT();
  //printf(">> trials << %d\n",fTrials);
}

Bool_t AliGenHerwig::CheckParton(const TParticle* parton1, const TParticle* parton2)
{
// Check the kinematic trigger condition
//
//Select events with parton max energy
    if(fPtHardMax < parton1->Pt()) return kFALSE;

// Select events within angular window
    Double_t eta[2];
    eta[0] = parton1->Eta();
    eta[1] = parton2->Eta();
    Double_t phi[2];
    phi[0] = parton1->Phi();
    phi[1] = parton2->Phi();
    Int_t    pdg[2]; 
    pdg[0] = parton1->GetPdgCode();
    pdg[1] = parton2->GetPdgCode();   
    printf("min %f, max %f\n",fPtHardMin, fPtHardMax);
    printf("Parton 1: %s, pT= %2.2f, eta = %1.2f, phi = %2.2f\n", parton1->GetName(),parton1->Pt(), eta[0],phi[0]*TMath::RadToDeg());
    printf("Parton 2: %s, pT= %2.2f, eta = %1.2f, phi = %2.2f\n", parton2->GetName(),parton2->Pt(), eta[1],phi[1]*TMath::RadToDeg());
    
    if (fProcess == kHeJets) {
      //Check if one of the 2 outgoing partons are in the eta-phi window
      for(Int_t i = 0; i < 2; i++)
	if ((eta[i] < fEtaMaxParton  && eta[i] > fEtaMinParton) &&
	    (phi[i] < fPhiMaxParton  && phi[i] > fPhiMinParton)) return  kTRUE ;
    }
    
    else {
      //Check if the gamma and the jet  are in the eta-phi window
      Int_t igj = 0;
      Int_t ijj = 0;
      if(pdg[0] == 22) ijj=1;
      else igj=1;
      if ((eta[ijj] < fEtaMaxParton   && eta[ijj] > fEtaMinParton) &&
	  (phi[ijj] < fPhiMaxParton   && phi[ijj] > fPhiMinParton)) {
	
	if ((eta[igj] < fEtaMaxGamma   && eta[igj] > fEtaMinGamma) &&
	    (phi[igj] < fPhiMaxGamma   && phi[igj] > fPhiMinGamma)) return  kTRUE;
	
      }
    }

    return kFALSE ;
}

void AliGenHerwig::AdjustWeights()
{
// Adjust the weights after generation of all events
    TParticle *part;
    Int_t ntrack=gAlice->GetMCApp()->GetNtrack();
    for (Int_t i=0; i<ntrack; i++) {
        part= gAlice->GetMCApp()->Particle(i);
        part->SetWeight(part->GetWeight()*fKineBias);
    }
}


void AliGenHerwig::KeepFullEvent()
{
    fKeep=1;
}

Bool_t AliGenHerwig::DaughtersSelection(const TParticle* iparticle, const TClonesArray* particles)
{
//
// Looks recursively if one of the daughters has been selected
//
//    printf("\n Consider daughters %d:",iparticle->GetPdgCode());
    Int_t imin=-1;
    Int_t imax=-1;
    Int_t i;
    Bool_t hasDaughters= (iparticle->GetFirstDaughter() >=0);
    Bool_t selected=kFALSE;
    if (hasDaughters) {
	imin=iparticle->GetFirstDaughter();
	imax=iparticle->GetLastDaughter();
	for (i=imin; i<= imax; i++){
	    TParticle *  jparticle       = (TParticle *) particles->At(i);
	    Int_t ip=jparticle->GetPdgCode();
	    if (KinematicSelection(jparticle,0)&&SelectFlavor(ip)) {
		selected=kTRUE; break;
	    }
	    if (DaughtersSelection(jparticle, particles)) {selected=kTRUE; break; }
	}
    } else {
	return kFALSE;
    }

    return selected;
}


Bool_t AliGenHerwig::SelectFlavor(Int_t pid) const
{
// Select flavor of particle
// 0: all
// 4: charm and beauty
// 5: beauty
    if (fFlavor == 0) return kTRUE;

    Int_t ifl=TMath::Abs(pid/100);
    if (ifl > 10) ifl/=10;
    return (fFlavor == ifl);
}

Bool_t AliGenHerwig::Stable(const TParticle*  particle) const
{
// Return true for a stable particle
//
    Int_t kf = TMath::Abs(particle->GetPdgCode());

    if ( (particle->GetFirstDaughter() < 0 ) || (kf == 1000*fFlavor+122))

    {
	return kTRUE;
    } else {
	return kFALSE;
    }
}

void AliGenHerwig::FinishRun()
{
  fHerwig->Hwefin();
}

void AliGenHerwig::FinishRunJimmy()
{
  fHerwig->Hwefin();
  fHerwig->Jmefin();

}


void AliGenHerwig::MakeHeader()
{
//
// Make header for the simulated event
// 
  if (fHeader) delete fHeader;
  fHeader = new AliGenHerwigEventHeader("Herwig");
//
// Event type  
    ((AliGenHerwigEventHeader*) fHeader)->SetProcessType(fHerwig->GetIHPRO());
//
// Number of trials
    ((AliGenHerwigEventHeader*) fHeader)->SetTrials(fTrials);
//
// Event weight (cross section)
    ((AliGenHerwigEventHeader*) fHeader)->SetWeight(fHerwig->GetEVWGT());
//
// Event Vertex 
    fHeader->SetPrimaryVertex(fVertex);
    fHeader->SetInteractionTime(fTime);
//
// Number of primaries
    fHeader->SetNProduced(fNprimaries);
//  Pass header
//
    AddHeader(fHeader);
    fHeader = 0x0;  
}