#ifndef __JAANET__JEVTWEIGHTFACTORMULTIPARTICLE__
#define __JAANET__JEVTWEIGHTFACTORMULTIPARTICLE__

#include <map>

#include "km3net-dataformat/offline/Evt.hh"
#include "km3net-dataformat/offline/Trk.hh"

#include "JLang/JClonable.hh"
#include "JLang/JPredicate.hh"
#include "JLang/JException.hh"

#include "JAAnet/JHead.hh"
#include "JAAnet/JFlux.hh"
#include "JAAnet/JAAnetToolkit.hh"
#include "JAAnet/JEvtWeightFactor.hh"
#include "JAAnet/JEvtWeightFactorHelper.hh"


/**
 * \author bjung
 */

namespace JAANET {
  
  using JLANG::JClonable;
  using JLANG::JValueOutOfRange;

  /**
   * Implementation of event-weight factor for multiple particle types.
   *
   * The first template argument corresponds to the type of event-weight factor class.
   * This class must contain the method `getFactor(const Evt&)`. 
   * The second template argument refers to the helper-class to the event-weight factor
   * of the type of the first template argument.
   */
  template<class JEvtWeightFactor_t>
  struct JEvtWeightFactorMultiParticle :
    public JClonable<JEvtWeightFactor_t, JEvtWeightFactorMultiParticle<JEvtWeightFactor_t> >,
    public std::map<int, JEvtWeightFactorHelper<JEvtWeightFactor_t> >
  {
    typedef JEvtWeightFactorHelper<JEvtWeightFactor_t>    JEvtWeightFactorHelper_t;
    typedef std::map<int, JEvtWeightFactorHelper_t>       map_type;

    
    /**
     * Default constructor.
     */
    JEvtWeightFactorMultiParticle() :
      map_type()
    {}


    /**
     * Constructor.
     *
     * The multi-particle flux function is created\n
     * listing all the primaries in the JHead::flux vector field of the given header.
     *
     * \param  header                 header
     * \param  factor                 factor
     */
    JEvtWeightFactorMultiParticle(const JHead&              header,
				  const JEvtWeightFactor_t& factor) :
      map_type()
    {
      if (!header.flux.empty()) {
	
	for (vector<JAANET::flux>::const_iterator i = header.flux.cbegin(); i != header.flux.cend(); ++i) {
	  insert(i->type, factor);
	}
	
      } else {

	THROW(JValueOutOfRange, "JEvtWeightFactorMultiParticle::JEvtWeightFactorMultiParticle(): Empty flux header-field.");
      }
    }
    
    
    /**
     * Constructor.
     *
     * \param  type                   particle PDG code
     * \param  factor                 event-weight factor
     * \param  args                   remaining pairs of PDG codes and event-weight factors
     */
    template<class ...Args>
    JEvtWeightFactorMultiParticle(const int                 type,
				  const JEvtWeightFactor_t& factor,
				  const Args&            ...args) :
      map_type()
    {
      insert(type, factor, args...);
    }


    /**
     * Insert pair of particle code and event-weight factor.
     *
     * \param  type                    particle PDG code
     * \param  factor                  event-weight factor
     */ 
    void insert(const int                 type,
		const JEvtWeightFactor_t& factor)
    {
      map_type::insert(std::make_pair(type, JEvtWeightFactorHelper_t(factor)));
    }
    

    /**
     * Insert pairs of particle codes and event-weight factors.
     *
     * \param  type                    particle PDG code
     * \param  factor                  event-weight factor
     * \param  args                    remaining pairs of PDG codes and event-weight factors
     */ 
    template<class ...Args>
    void insert(const int                 type,
		const JEvtWeightFactor_t& factor,
		const Args&            ...args)
    {
      insert(type, factor);
      insert(args...);
    }


    /**
     * Get weight factor of given event.
     *
     * \param  evt               event
     * \return                   weight-factor for given event
     */
    virtual double getFactor(const Evt& evt) const override
    {
      using namespace std;
      using namespace JPP;

      vector<Trk>::const_iterator primary = find_if(evt.mc_trks.cbegin(),
      						    evt.mc_trks.cend(),
       						    make_predicate(&Trk::is_primary, true));
      
      if (primary != evt.mc_trks.cend()) {
	
	return this->at(primary->type).getFactor(evt);
	
      } else if (has_neutrino(evt)) {
	
	const Trk& neutrino = get_neutrino(evt);

	return this->at(neutrino.type).getFactor(evt);
	
      } else {
	
	THROW(JValueOutOfRange, "JEvtWeightFactorMultiParticle::getFactor(): No primary track found for event " << evt.id << ".");
      }
    }
  };


  /** 
   * Type-definition of multi-particle event-weight factor for fluxes.
   */
  typedef JEvtWeightFactorMultiParticle<JFlux>      JFluxMultiParticle;
}

#endif