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// $Id: G4DNAChampionElasticModel.cc,v 1.10 2009/11/03 15:04:25 sincerti Exp $
// GEANT4 tag $Name: geant4-09-03 $
//

#include "G4DNAChampionElasticModel.hh"

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using namespace std;

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G4DNAChampionElasticModel::G4DNAChampionElasticModel(const G4ParticleDefinition*,
                                             const G4String& nam)
:G4VEmModel(nam),isInitialised(false)
{

  killBelowEnergy = 8.23*eV; // Minimum e- energy for energy loss by excitation
  lowEnergyLimit = 0 * eV; 
  lowEnergyLimitOfModel = 7.4 * eV; // The model lower energy is 7.4 eV
  highEnergyLimit = 10 * MeV;
  SetLowEnergyLimit(lowEnergyLimit);
  SetHighEnergyLimit(highEnergyLimit);

  verboseLevel= 0;
  // Verbosity scale:
  // 0 = nothing 
  // 1 = warning for energy non-conservation 
  // 2 = details of energy budget
  // 3 = calculation of cross sections, file openings, sampling of atoms
  // 4 = entering in methods
  
  if( verboseLevel>0 ) 
  { 
    G4cout << "Champion Elastic model is constructed " << G4endl
           << "Energy range: "
           << lowEnergyLimit / eV << " eV - "
           << highEnergyLimit / MeV << " MeV"
           << G4endl;
  }
}

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G4DNAChampionElasticModel::~G4DNAChampionElasticModel()
{  
  // For total cross section
  
  std::map< G4String,G4DNACrossSectionDataSet*,std::less<G4String> >::iterator pos;
  for (pos = tableData.begin(); pos != tableData.end(); ++pos)
  {
    G4DNACrossSectionDataSet* table = pos->second;
    delete table;
  }

   // For final state
   
   eVecm.clear();

}

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void G4DNAChampionElasticModel::Initialise(const G4ParticleDefinition* /*particle*/,
                                       const G4DataVector& /*cuts*/)
{

  if (verboseLevel > 3)
    G4cout << "Calling G4DNAChampionElasticModel::Initialise()" << G4endl;

  // Energy limits
  
  if (LowEnergyLimit() < lowEnergyLimit)
  {
    G4cout << "G4DNAChampionElasticModel: low energy limit increased from " << 
	LowEnergyLimit()/eV << " eV to " << lowEnergyLimit/eV << " eV" << G4endl;
    SetLowEnergyLimit(lowEnergyLimit);
    }

  if (HighEnergyLimit() > highEnergyLimit)
  {
    G4cout << "G4DNAChampionElasticModel: high energy limit decreased from " << 
        HighEnergyLimit()/MeV << " MeV to " << highEnergyLimit/MeV << " MeV" << G4endl;
    SetHighEnergyLimit(highEnergyLimit);
  }

  // Reading of data files 
  
  G4double scaleFactor = 1e-16*cm*cm;

  G4String fileElectron("dna/sigma_elastic_e_champion");

  G4ParticleDefinition* electronDef = G4Electron::ElectronDefinition();
  G4String electron;
 
  if (electronDef != 0)
  {
    // For total cross section
    
    electron = electronDef->GetParticleName();

    tableFile[electron] = fileElectron;

    G4DNACrossSectionDataSet* tableE = new G4DNACrossSectionDataSet(new G4LogLogInterpolation, eV,scaleFactor );
    tableE->LoadData(fileElectron);
    tableData[electron] = tableE;
    
    // For final state
    
    char *path = getenv("G4LEDATA");
 
    if (!path)
    G4Exception("G4FinalStateElasticChampion::Initialise: G4LEDATA environment variable not set");

    std::ostringstream eFullFileName;
    eFullFileName << path << "/dna/sigmadiff_elastic_e_champion.dat";
    std::ifstream eDiffCrossSection(eFullFileName.str().c_str());
     
    if (!eDiffCrossSection) G4Exception("G4DNAChampionElasticModel::Initialise: error opening electron DATA FILE");
      
    eTdummyVec.push_back(0.);

    while(!eDiffCrossSection.eof())
    {
	double tDummy;
	double eDummy;
	eDiffCrossSection>>tDummy>>eDummy;

	// SI : mandatory eVecm initialization
        if (tDummy != eTdummyVec.back()) 
        { 
          eTdummyVec.push_back(tDummy); 
          eVecm[tDummy].push_back(0.);
        }
	  
        eDiffCrossSection>>eDiffCrossSectionData[tDummy][eDummy];

	// SI : only if not end of file reached !
        if (!eDiffCrossSection.eof()) eDiffCrossSectionData[tDummy][eDummy]*=scaleFactor;
	  
        if (eDummy != eVecm[tDummy].back()) eVecm[tDummy].push_back(eDummy);
          
    }

    // End final state
  
  }
  else G4Exception("G4DNAChampionElasticModel::Initialise: electron is not defined");
  
  if (verboseLevel > 2) 
    G4cout << "Loaded cross section files for Champion Elastic model" << G4endl;

  if( verboseLevel>0 ) 
  { 
    G4cout << "Champion Elastic model is initialized " << G4endl
           << "Energy range: "
           << LowEnergyLimit() / eV << " eV - "
           << HighEnergyLimit() / MeV << " MeV"
           << G4endl;
  }

  if(!isInitialised) 
  {
    isInitialised = true;
  
    if(pParticleChange)
      fParticleChangeForGamma = reinterpret_cast<G4ParticleChangeForGamma*>(pParticleChange);
    else
      fParticleChangeForGamma = new G4ParticleChangeForGamma();
  }    

  // InitialiseElementSelectors(particle,cuts);

  // Test if water material

  flagMaterialIsWater= false;
  densityWater = 0;

  const G4ProductionCutsTable* theCoupleTable = G4ProductionCutsTable::GetProductionCutsTable();

  if(theCoupleTable) 
  {
    G4int numOfCouples = theCoupleTable->GetTableSize();
  
    if(numOfCouples>0) 
    {
	  for (G4int i=0; i<numOfCouples; i++) 
	  {
	    const G4MaterialCutsCouple* couple = theCoupleTable->GetMaterialCutsCouple(i);
	    const G4Material* material = couple->GetMaterial();

            if (material->GetName() == "G4_WATER") 
            {
              G4double density = material->GetAtomicNumDensityVector()[1];
	      flagMaterialIsWater = true; 
	      densityWater = density; 
	      
	      if (verboseLevel > 3) 
              G4cout << "****** Water material is found with density(cm^-3)=" << density/(cm*cm*cm) << G4endl;
            }
  
          }

    } // if(numOfCouples>0)

  } // if (theCoupleTable)

}

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G4double G4DNAChampionElasticModel::CrossSectionPerVolume(const G4Material*,
					   const G4ParticleDefinition* p,
					   G4double ekin,
					   G4double,
					   G4double)
{
  if (verboseLevel > 3)
    G4cout << "Calling CrossSectionPerVolume() of G4DNAChampionElasticModel" << G4endl;

 // Calculate total cross section for model

 G4double sigma=0;
 
 if (flagMaterialIsWater)
 {
  const G4String& particleName = p->GetParticleName();

  if (ekin < highEnergyLimit)
  {
      //SI : XS must not be zero otherwise sampling of secondaries method ignored
      if (ekin < lowEnergyLimitOfModel) ekin = lowEnergyLimitOfModel;
      //      
      
	std::map< G4String,G4DNACrossSectionDataSet*,std::less<G4String> >::iterator pos;
	pos = tableData.find(particleName);
	
	if (pos != tableData.end())
	{
	  G4DNACrossSectionDataSet* table = pos->second;
	  if (table != 0)
	  {
	    sigma = table->FindValue(ekin);
	  }
	}
	else
	{
	    G4Exception("G4DNAChampionElasticModel::ComputeCrossSectionPerVolume: attempting to calculate cross section for wrong particle");
	}
  }

  if (verboseLevel > 3)
  {
    G4cout << "---> Kinetic energy(eV)=" << ekin/eV << G4endl;
    G4cout << " - Cross section per water molecule (cm^2)=" << sigma/cm/cm << G4endl;
    G4cout << " - Cross section per water molecule (cm^-1)=" << sigma*densityWater/(1./cm) << G4endl;
  } 

 } // if (flagMaterialIsWater)
         
 return sigma*densityWater;		   
}

//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....

void G4DNAChampionElasticModel::SampleSecondaries(std::vector<G4DynamicParticle*>* /*fvect*/,
					      const G4MaterialCutsCouple* /*couple*/,
					      const G4DynamicParticle* aDynamicElectron,
					      G4double,
					      G4double)
{

  if (verboseLevel > 3)
    G4cout << "Calling SampleSecondaries() of G4DNAChampionElasticModel" << G4endl;

  G4double electronEnergy0 = aDynamicElectron->GetKineticEnergy();
  
  if (electronEnergy0 < killBelowEnergy)
  {
    fParticleChangeForGamma->ProposeTrackStatus(fStopAndKill);
    fParticleChangeForGamma->ProposeLocalEnergyDeposit(electronEnergy0);
    return ;
  }

  if (electronEnergy0>= killBelowEnergy && electronEnergy0 < highEnergyLimit)
  {  
    G4double cosTheta = RandomizeCosTheta(electronEnergy0);
  
    G4double phi = 2. * pi * G4UniformRand();

    G4ThreeVector zVers = aDynamicElectron->GetMomentumDirection();
    G4ThreeVector xVers = zVers.orthogonal();
    G4ThreeVector yVers = zVers.cross(xVers);

    G4double xDir = std::sqrt(1. - cosTheta*cosTheta);
    G4double yDir = xDir;
    xDir *= std::cos(phi);
    yDir *= std::sin(phi);

    G4ThreeVector zPrimeVers((xDir*xVers + yDir*yVers + cosTheta*zVers));

    fParticleChangeForGamma->ProposeMomentumDirection(zPrimeVers.unit()) ;

    fParticleChangeForGamma->SetProposedKineticEnergy(electronEnergy0);
  }

}

//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....

G4double G4DNAChampionElasticModel::DifferentialCrossSection
  (G4ParticleDefinition * particleDefinition, G4double k, G4double theta) 							  
{

  G4double sigma = 0.;
  G4double valueT1 = 0;
  G4double valueT2 = 0;
  G4double valueE21 = 0;
  G4double valueE22 = 0;
  G4double valueE12 = 0;
  G4double valueE11 = 0;
  G4double xs11 = 0;   
  G4double xs12 = 0; 
  G4double xs21 = 0; 
  G4double xs22 = 0; 

  //SI : ensure the correct computation of cross section at the 180*deg limit
  if (theta==180.) theta=theta-1e-9;

  if (particleDefinition == G4Electron::ElectronDefinition()) 
  {
    std::vector<double>::iterator t2 = std::upper_bound(eTdummyVec.begin(),eTdummyVec.end(), k);
    std::vector<double>::iterator t1 = t2-1;
 
    std::vector<double>::iterator e12 = std::upper_bound(eVecm[(*t1)].begin(),eVecm[(*t1)].end(), theta);
    std::vector<double>::iterator e11 = e12-1;
	  
    std::vector<double>::iterator e22 = std::upper_bound(eVecm[(*t2)].begin(),eVecm[(*t2)].end(), theta);
    std::vector<double>::iterator e21 = e22-1;
	  	
    valueT1  =*t1;
    valueT2  =*t2;
    valueE21 =*e21;
    valueE22 =*e22;
    valueE12 =*e12;
    valueE11 =*e11;

    xs11 = eDiffCrossSectionData[valueT1][valueE11];
    xs12 = eDiffCrossSectionData[valueT1][valueE12];
    xs21 = eDiffCrossSectionData[valueT2][valueE21];
    xs22 = eDiffCrossSectionData[valueT2][valueE22];

}
     
  G4double xsProduct = xs11 * xs12 * xs21 * xs22;
  
  if (xs11==0 || xs12==0 ||xs21==0 ||xs22==0) return (0.);
     
  if (xsProduct != 0.)
  {
    sigma = QuadInterpolator(  valueE11, valueE12, 
    			       valueE21, valueE22, 
			       xs11, xs12, 
			       xs21, xs22, 
			       valueT1, valueT2, 
			       k, theta );
  }

  return sigma;
}

//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....

G4double G4DNAChampionElasticModel::LinLogInterpolate(G4double e1, 
						        G4double e2, 
						        G4double e, 
						        G4double xs1, 
						        G4double xs2)
{
  G4double d1 = std::log(xs1);
  G4double d2 = std::log(xs2);
  G4double value = std::exp(d1 + (d2 - d1)*(e - e1)/ (e2 - e1));
  return value;
}

//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....

G4double G4DNAChampionElasticModel::LogLogInterpolate(G4double e1, 
						        G4double e2, 
						        G4double e, 
						        G4double xs1, 
						        G4double xs2)
{
  G4double a = (std::log10(xs2)-std::log10(xs1)) / (std::log10(e2)-std::log10(e1));
  G4double b = std::log10(xs2) - a*std::log10(e2);
  G4double sigma = a*std::log10(e) + b;
  G4double value = (std::pow(10.,sigma));
  return value;
}

//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....

G4double G4DNAChampionElasticModel::QuadInterpolator(G4double e11, G4double e12, 
						       G4double e21, G4double e22, 
						       G4double xs11, G4double xs12, 
						       G4double xs21, G4double xs22, 
						       G4double t1, G4double t2, 
						       G4double t, G4double e)
{
// Log-Log
/*
  G4double interpolatedvalue1 = LogLogInterpolate(e11, e12, e, xs11, xs12);
  G4double interpolatedvalue2 = LogLogInterpolate(e21, e22, e, xs21, xs22);
  G4double value = LogLogInterpolate(t1, t2, t, interpolatedvalue1, interpolatedvalue2);
*/

// Lin-Log
  G4double interpolatedvalue1 = LinLogInterpolate(e11, e12, e, xs11, xs12);
  G4double interpolatedvalue2 = LinLogInterpolate(e21, e22, e, xs21, xs22);
  G4double value = LinLogInterpolate(t1, t2, t, interpolatedvalue1, interpolatedvalue2);
  return value;
}

//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....

G4double G4DNAChampionElasticModel::RandomizeCosTheta(G4double k) 
{
 // ***** Similar method as for screened Rutherford scattering

 G4int iMax=180;
 G4double max=0;
 G4double tmp=0;
 
 // Look for maximum :
 for (G4int i=0; i<iMax; i++) 
 {
   tmp = DifferentialCrossSection(G4Electron::ElectronDefinition(),k/eV,G4double(i)*180./(iMax-1));
   if (tmp>max) max = tmp;
 }

 G4double oneOverMax=0;
 if (max!=0) oneOverMax = 1./max;
  
 G4double cosTheta = 0.;
 G4double fCosTheta = 0.;
  
 do
 {
    cosTheta = 2. * G4UniformRand() - 1.;
    fCosTheta = oneOverMax * DifferentialCrossSection(G4Electron::ElectronDefinition(),k/eV,std::acos(cosTheta)*180./pi);
 }
 while (fCosTheta < G4UniformRand());

 if (verboseLevel > 3)
 {
   G4cout << "---> Cos(theta)=" << cosTheta << G4endl;
 } 

 return cosTheta; 
}
