#ifndef __JPHYSICS__JRADIATIONSOURCE__
#define __JPHYSICS__JRADIATIONSOURCE__

#include "JLang/JSharedPointer.hh"

#include "JPhysics/JRadiation.hh"
#include "JPhysics/JDIS.hh"
#include "JPhysics/JConstants.hh"


/**
 * \author mdejong
 */

namespace JPHYSICS {}
namespace JPP { using namespace JPHYSICS; }

namespace JPHYSICS {

  using JLANG::JSharedPointer;
  

  /**
   * Interface for calculation of inverse interaction length and shower energy.
   */
  class JRadiationInterface {
  public:
    /**
     * Constructor.
     *
     * \param  id              radiation identifier
     */
    JRadiationInterface(const int id) :
      id(id)
    {}

    /**
     * Virtual destructor.
     */
    virtual ~JRadiationInterface()
    {}

    /**
     * Get radiation identifer.
     *
     * \return        identifier
     */
    int getID() const
    {
      return id;
    }

    /**
     * Get inverse interaction length.
     *
     * \param  E      muon energy [GeV]
     * \return        inverse interaction length [m^-1]
     */
    virtual double getInverseInteractionLength(const double E) const = 0;

    /**
     * Get energy of shower.
     *
     * \param  E      muon   energy [GeV]
     * \return        shower energy [GeV]
     */
    virtual double getEnergyOfShower(const double E) const = 0;

    /**
     * Get RMS of scattering angle.
     *
     * \param  E      muon   energy [GeV]
     * \param  Es     shower energy [GeV]
     * \return        RMS scattering angle [rad]
     */
    virtual double getThetaRMS(const double E, const double Es) const = 0;

  private:
    const int id;
  };


  /**
   * Implementation for calculation of inverse interaction length and shower energy.
   *
   * This class implements the JRadiationInterface interface.\n
   * N.B: This class owns the object pointed to using JLANG::JSharedPointer.
   */
  class JRadiationSource :
    public JRadiationInterface,
    public JSharedPointer<JRadiation>,
    public JRadiationSource_t
  {
  public:
    /**
     * Constructor.
     *
     * \param  id              radiation identifier
     * \param  radiation       pointer to valid JRadition object
     * \param  density         mass density of radiation material [gr/cm³]
     * \param  source          pointers to member methods of JRadiation
     */
    JRadiationSource(const int                         id,
		     const JSharedPointer<JRadiation>& radiation,
		     const double                      density,
		     const JRadiationSource_t          source) :
      JRadiationInterface(id),
      JSharedPointer<JRadiation>(radiation),
      JRadiationSource_t(source),
      rho(density)
    {}


    /**
     * Get inverse interaction length.
     *
     * \param  E      muon energy [GeV]
     * \return        inverse interaction length [m^-1]
     */
    virtual double getInverseInteractionLength(const double E) const override 
    { 
      return ((*this)->*sigma)(E) * rho * 1.0e6;
    }


    /**
     * Get energy of shower.
     *
     * \param  E      muon   energy [GeV]
     * \return        shower energy [GeV]
     */
    virtual double getEnergyOfShower(const double E) const override 
    { 
      return ((*this)->*eloss)(E);
    }


    /**
     * Get RMS of scattering angle.
     *
     * \param  E      muon   energy [GeV]
     * \param  Es     shower energy [GeV]
     * \return        RMS scattering angle [rad]
     */
    virtual double getThetaRMS(const double E, const double Es) const override
    {
      return ((*this)->*theta)(E, Es/E);
    }

  protected:
    const double rho;
  };


  /**
   * Implementation for calculation of inverse interaction length and shower energy due to deep-inelastic muon-nucleon scattering.
   *
   * This class implements the JRadiationInterface interface.
   */
  class JDISSource :
    public JRadiationInterface,
    public JDIS
  {
  public:
    /**
     * Constructor.
     *
     * \param  id              radiation identifier
     * \param  density         mass density of radiation material [gr/cm³]
     */
    JDISSource(const int    id,
	       const double density) :
      JRadiationInterface(id),
      rho(density)
    {}
    
    
    /**
     * Get inverse interaction length.
     *
     * \param  E      muon energy [GeV]
     * \return        inverse interaction length [m^-1]
     */
    virtual double getInverseInteractionLength(const double E) const override 
    {
      return this->getCrossSection(E) * (rho / NUCLEON_MOLAR_MASS) * AVOGADRO * 1.0e2;
    }


    /**
     * Get energy of shower.
     *
     * \param  E      muon   energy [GeV]
     * \return        shower energy [GeV]
     */
    virtual double getEnergyOfShower(const double E) const override 
    { 
      return this->getE(E);
    }


    /**
     * Get RMS of scattering angle.
     *
     * \param  E      muon   energy [GeV]
     * \param  Es     shower energy [GeV]
     * \return        RMS scattering angle [rad]
     */
    virtual double getThetaRMS(const double E, const double Es) const override
    {
      return static_cast<const JDIS*>(this)->getThetaRMS(E, Es/E);
    }
    
  protected:
    const double rho;
  };
}    

#endif