/** @file CbmStsParAsic.cxx
 ** @author Volker Friese <v.friese@gsi.de>
 ** @date 23.03.2020
 **/
#include "CbmStsParAsic.h"

#include <TF1.h>                // for TF1
#include <TMath.h>              // for Exp

#include <assert.h>             // for assert
#include <sstream>              // for operator<<, basic_ostream, stringstream

ClassImp(CbmStsParAsic)

// -----   Constructor   ---------------------------------------------------
CbmStsParAsic::CbmStsParAsic(UShort_t nAdc, Double_t dynRange,
                             Double_t threshold, Double_t timeResol,
                             Double_t deadTime, Double_t noise,
                             Double_t znr) {
  Set(nAdc, dynRange, threshold, timeResol, deadTime, noise, znr);
}
// -------------------------------------------------------------------------



// -----   Copy constructor   ----------------------------------------------
CbmStsParAsic::CbmStsParAsic(const CbmStsParAsic& other) {
  Set(other.fNofAdc, other.fDynRange, other.fThreshold, other.fTimeResolution,
      other.fDeadTime, other.fNoise, other.fZeroNoiseRate);
}
// -------------------------------------------------------------------------



// -----   Copy assignment operator   --------------------------------------
CbmStsParAsic& CbmStsParAsic::operator=(const CbmStsParAsic& other) {
  Set(other.fNofAdc, other.fDynRange, other.fThreshold, other.fTimeResolution,
      other.fDeadTime, other.fNoise, other.fZeroNoiseRate);
  return *this;
}
// -------------------------------------------------------------------------



// -----   Destructor   ----------------------------------------------------
CbmStsParAsic::~CbmStsParAsic() {
  if ( fNoiseCharge ) delete fNoiseCharge;
}
// -------------------------------------------------------------------------



// -----  ADC channel from charge   ----------------------------------------
Short_t CbmStsParAsic::ChargeToAdc(Double_t charge) const {
  if ( charge < fThreshold ) return -1;                       // Underflow
  if ( charge >= fThreshold + fDynRange ) return fNofAdc - 1; // Overflow
  return Short_t( (charge - fThreshold) / fDynRange * Double_t(fNofAdc) );
}
// -------------------------------------------------------------------------



// -----   Single-channel noise rate   -------------------------------------
Double_t CbmStsParAsic::GetNoiseRate() const {
  if ( fNoise == 0. ) return 0.;
  Double_t ratio = fThreshold / fNoise;
  return 0.5 * fZeroNoiseRate * TMath::Exp( -0.5 * ratio * ratio );
}
// -------------------------------------------------------------------------



// -----   Random charge of a noise signal   -------------------------------
Double_t CbmStsParAsic::GetRandomNoiseCharge() const {
  assert(fIsInit);
  return fNoiseCharge->GetRandom();
}
// -------------------------------------------------------------------------



// -----   Intialise the noise charge distribution   -----------------------
void CbmStsParAsic::Init() {
  if ( fNoiseCharge ) delete fNoiseCharge;
  fNoiseCharge = new TF1("Noise Charge", "TMath::Gaus(x, [0], [1])",
                         fThreshold, 10. * fNoise);
  fNoiseCharge->SetParameters(0., fNoise);
  fIsInit = kTRUE;
}
// -------------------------------------------------------------------------



// -----   Set the parameters   ---------------------------------------------
void CbmStsParAsic::Set(UShort_t nAdc, Double_t dynRange,
                        Double_t threshold, Double_t timeResol,
                        Double_t deadTime, Double_t noise,
                        Double_t zeroNoiseRate,
                        std::set<UShort_t> deadChannels) {

  // Assert validity of parameters
  assert( dynRange > 0. );
  assert( threshold > 0. );
  assert( timeResol > 0. );
  assert( deadTime >= 0. );
  assert( noise >= 0. );
  assert( zeroNoiseRate >= 0. );

  fNofAdc          = nAdc;
  fDynRange        = dynRange;
  fThreshold       = threshold;
  fTimeResolution  = timeResol;
  fDeadTime        = deadTime;
  fNoise           = noise;
  fZeroNoiseRate   = zeroNoiseRate;
  fDeadChannels    = deadChannels;

  Init();

}
// --------------------------------------------------------------------------



// ----- String output   ----------------------------------------------------
std::string CbmStsParAsic::ToString() const {
  std::stringstream ss;
  ss << "nAdc " << fNofAdc << " | dynRange " << fDynRange << " e | thresh. "
      << fThreshold << " e | tResol " << fTimeResolution << " ns | deadTime "
      << fDeadTime << " ns | noise " << fNoise << " e | ZNR "
      << fZeroNoiseRate << "/ns | SCNR " << GetNoiseRate() << "/ns";
  return ss.str();
}
// --------------------------------------------------------------------------