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// $Id: G4DNABornExcitationModel.cc,v 1.3 2009/02/16 11:00:11 sincerti Exp $
// GEANT4 tag $Name: geant4-09-03-beta-cand-01 $
//

#include "G4DNABornExcitationModel.hh"

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using namespace std;

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G4DNABornExcitationModel::G4DNABornExcitationModel(const G4ParticleDefinition*,
                                             const G4String& nam)
:G4VEmModel(nam),isInitialised(false)
{

  lowEnergyLimit = 500 * keV; 
  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
  
  //
  
  table = 0;
  
  //
  
  G4cout << "Born excitation model is constructed " << G4endl
         << "Energy range: "
         << lowEnergyLimit / keV << " keV - "
         << highEnergyLimit / MeV << " MeV"
         << G4endl;

}

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G4DNABornExcitationModel::~G4DNABornExcitationModel()
{ 
  // Cross section
  delete table;
}

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void G4DNABornExcitationModel::Initialise(const G4ParticleDefinition* /*particle*/,
                                       const G4DataVector& /*cuts*/)
{

  if (verboseLevel > 3)
    G4cout << "Calling G4DNABornExcitationModel::Initialise()" << G4endl;

  // Energy limits
  
  if (LowEnergyLimit() < lowEnergyLimit)
  {
    G4cout << "G4DNABornExcitationModel: low energy limit increased from " << 
	LowEnergyLimit()/keV << " keV to " << lowEnergyLimit/keV << " keV" << G4endl;
    SetLowEnergyLimit(lowEnergyLimit);
  }

  if (HighEnergyLimit() > highEnergyLimit)
  {
    G4cout << "G4DNABornExcitationModel: high energy limit decreased from " << 
        HighEnergyLimit()/MeV << " MeV to " << highEnergyLimit/MeV << " MeV" << G4endl;
    SetHighEnergyLimit(highEnergyLimit);
  }

  //
  
  if (table == 0)
  {
    table = new G4DNACrossSectionDataSet(new G4LogLogInterpolation, eV,(1e-22/3.343)*m*m );
    table->LoadData("dna/sigma_excitation_p_born");
  }

  G4cout << "Born excitation model is initialized " << G4endl
         << "Energy range: "
         << LowEnergyLimit() / keV << " keV - "
         << 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();

            size_t j = material->GetNumberOfElements();
            while (j>0)
            {
               j--;
               const G4Element* element(material->GetElement(j));
               if (element->GetZ() == 8.)
	       {
	          G4double density = material->GetAtomicNumDensityVector()[j];
                  if (density > 0.) 
		  { 
		    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 G4DNABornExcitationModel::CrossSectionPerVolume(const G4Material*,
					   const G4ParticleDefinition* particleDefinition,
					   G4double k,
					   G4double,
					   G4double)
{
  if (verboseLevel > 3)
    G4cout << "Calling CrossSectionPerVolume() of G4DNABornExcitationModel" << G4endl;

 // Calculate total cross section for model

  G4double crossSection=0;
  
  if (flagMaterialIsWater)
  {
    if (particleDefinition == G4Proton::ProtonDefinition())
    {
      if (k >= lowEnergyLimit && k < highEnergyLimit)
      {
        crossSection = table->FindValue(k); 
      }

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

 return crossSection*densityWater;		   

}

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void G4DNABornExcitationModel::SampleSecondaries(std::vector<G4DynamicParticle*>* /*fvect*/,
					      const G4MaterialCutsCouple* /*couple*/,
					      const G4DynamicParticle* aDynamicParticle,
					      G4double,
					      G4double)
{

  if (verboseLevel > 3)
    G4cout << "Calling SampleSecondaries() of G4DNABornExcitationModel" << G4endl;

  G4double k = aDynamicParticle->GetKineticEnergy();
  
  G4int level = RandomSelect(k);
  G4double excitationEnergy = waterStructure.ExcitationEnergy(level);
  G4double newEnergy = k - excitationEnergy;
  
  if (newEnergy > 0)
  {
      fParticleChangeForGamma->ProposeMomentumDirection(aDynamicParticle->GetMomentumDirection());
      fParticleChangeForGamma->SetProposedKineticEnergy(newEnergy);
      fParticleChangeForGamma->ProposeLocalEnergyDeposit(excitationEnergy);
  }

}

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G4int G4DNABornExcitationModel::RandomSelect(G4double k)
{   
  G4int level = 0;

  G4double* valuesBuffer = new G4double[table->NumberOfComponents()];

  const size_t n(table->NumberOfComponents());
  size_t i(n);
  G4double value = 0.;
  
  while (i>0)
  { 
    i--;
    valuesBuffer[i] = table->GetComponent(i)->FindValue(k);
    value += valuesBuffer[i];
  }
  
  value *= G4UniformRand();
  
  i = n;
  
  while (i > 0)
  {
    i--;
      
    if (valuesBuffer[i] > value)
    {
      delete[] valuesBuffer;
      return i;
    }
      value -= valuesBuffer[i];
  }

  if (valuesBuffer) delete[] valuesBuffer;

  return level;
}