#ifndef AMISIC_Perturbative_MI_Process_H
#define AMISIC_Perturbative_MI_Process_H
/*!
  \file MI_Process.H
  \brief Declares the class MI_Process
*/

#include "ATOOLS/Phys/Particle.H"
#include "ATOOLS/Phys/Momenta_Stretcher.H"
#include "EXTRA_XS/Main/ME2_Base.H"

namespace AMISIC {
  
  class XS_Base {
  protected:
    std::string m_name;
    double      m_Ms, m_Mt, m_Mu, m_lastxs, m_shat, m_that, m_uhat;
    std::vector<std::vector<int> > m_colours;
    std::vector<double>            m_masses, m_masses2;
  public:
    XS_Base();
    explicit XS_Base(const std::vector<double> & masses);
    virtual ~XS_Base();
    
    virtual void Calc(const double & s,const double & t,const double & u)=0;
    virtual bool SetColours(const ATOOLS::Flavour_Vector & flavs)=0;
    virtual double operator()() { return m_lastxs; }
    virtual const int & Colour(const size_t & i,const size_t & j) const {
      return m_colours[i][j];
    }
    virtual const std::string & Name() const { return m_name; }
  };

#define DECLARE_XSBASE_GETTER(NAME,TAG)				     \
  DECLARE_GETTER(NAME,TAG,AMISIC::XS_Base,ATOOLS::Flavour_Vector);   \
  void ATOOLS::Getter<AMISIC::XS_Base,ATOOLS::Flavour_Vector,NAME>:: \
  PrintInfo(std::ostream &str,const size_t width) const		     \
  {								     \
    str<<#TAG;							     \
  }


  class MI_Process {
  private:
    std::string                  m_name;
    ATOOLS::Momenta_Stretcher    m_stretcher;
    std::vector<ATOOLS::Flavour> m_flavs;
    std::vector<double>          m_masses, m_masses2;
    std::vector<ATOOLS::Vec4D>   m_momenta;
    XS_Base   * p_me2;
    double      m_emin;
    bool        m_masslessIS;

    bool AllowedKinematics(const double & Ehat);
    void MasslessKinematics(const double & pt2,const double & phi,
			    const double & y3,const double & y4);
  public:
    explicit MI_Process(const std::vector<ATOOLS::Flavour> & flavs);
    ~MI_Process();

    bool MakeKinematics(const double & pt2,const double & y3,const double & y4,
			const double & Ehat);
    ATOOLS::Particle * GetParticle(const size_t & i);

    inline const ATOOLS::Flavour & Flav(const size_t & i) const {
      return m_flavs[i];
    }
    inline const ATOOLS::Vec4D & Momentum(size_t i) const {
      return m_momenta[i];
    }
    inline void SetME2(XS_Base * me2) { p_me2 = me2; }
    inline double operator()() const { return (*p_me2)(); }
    inline bool SetColours() const { return p_me2->SetColours(m_flavs); }
    inline const std::string & Name() const { return m_name; }
  };
}

#endif