////////////////////////////////////////////////////////////////////////
/// \class RAT::IBDCrossSec
///  \author Nuno Barros <nfbarros@hep.upenn.edu> -- contact person
///  \date 17-Oct-2016
///
///  \brief Standalone, easily expandable class to calculate IBD cross sections.
///
///  REVISION HISTORY:
///  - 17-Oct-2016 : Nuno Barros <nfbarros@hep.upenn.edu>
///                 - Initial revision.
///
////////////////////////////////////////////////////////////////////////

#ifndef SRC_GEN_IBDCROSSSEC_HH_
#define SRC_GEN_IBDCROSSSEC_HH_

#include <map>
#include <string>
#include <RAT/Log.hh>

class TFile;
class TH2F;

using std::string;
using std::map;

namespace RAT {
class IBDCrossSecMessenger;

class IBDCrossSec {
public:

  enum Strategy {Vogel=0,VogelTable};

  IBDCrossSec();
  virtual ~IBDCrossSec();

  short int GetStrategy() const {
    return _strategy;
  }

  void SetStrategy(Strategy strat);

  double dSigmadTheta(const double Enu, const double cosThetaLab);

  double Sigma(const double Enu);

  static string GetStrategyName(Strategy str) {
    return _str_map.find(str)->second;
  }

  static Strategy GetStrategyCode(string str) {
    map<Strategy,string>::const_iterator it;
    for (it = _str_map.begin(); it != _str_map.end(); ++it) {
      if(it->second == str) {
        return it->first;
      } else {
        Log::Die("Strategy [" + str + "] does not exist.");
      }
    }
  }

protected:
  // Concrete cross section implementations using different strategies
  double dSigmadThetaVogel(const double Enu, const double cosThetaLab);
  double dSigmadThetaVogelTable(const double Enu, const double cosThetaLab);
  void LoadTable(Strategy strat);
private:

  static map<Strategy,string> init_map() {
    map<Strategy,string> m;
    m[Vogel] = "Vogel";
    m[VogelTable] = "VogelTable";

    return m;
  }
  static const map<Strategy,string> _str_map;

  Strategy _strategy;
  TFile *_input_file;
  TH2F* _xs_table;

  IBDCrossSecMessenger *fMessenger;
};

} /* namespace RAT */

#endif /* SRC_GEN_IBDCROSSSEC_HH_ */