#include <iostream>
#include <iomanip>
#include <string>
#include <set>

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

#include "JLang/JException.hh"

#include "JAAnet/JAAnetToolkit.hh"
#include "JAAnet/JEvtWeightFactorFunction.hh"
#include "JAAnet/JEvtWeightFactorMultiParticle.hh"
#include "JAAnet/JFlux.hh"

#include "JSupport/JLimit.hh"
#include "JSupport/JMultipleFileScanner.hh"
#include "JSupport/JEvtWeightFileScannerSet.hh"

#include "Jeep/JPrint.hh"
#include "Jeep/JParser.hh"
#include "Jeep/JMessage.hh"
#include "Jeep/JProperties.hh"


namespace {

  using JLANG::JValueOutOfRange;
  using JLANG::JNullPointerException;


  /**
   * Set flux of given event to zero.
   *
   * \param  evt             event
   * \return                 zero         [GeV * m^-2 * sr^-1 * s^-1]
   */
  inline double zeroFlux(const Evt& evt)
  {
    return 0.0;
  }


  /**
   * Example function object for constant flux.
   */
  struct JFlatFlux
  {
    /**
     * Default constructor.
     */
    JFlatFlux() :
      flux(0.0)
    {}
    
    
    /**
     * Constructor.
     *
     * \param                  flux         [GeV * m^-2 * sr^-1 * s^-1]
     */
    JFlatFlux(const double flux) :
      flux(flux)
    {}
    
    
    /**
     * Get flux of given event.
     *
     * \param  evt             event
     * \return                 flux         [GeV * m^-2 * sr^-1 * s^-1]
     */
    double operator()(const Evt& evt) const
    {
      return flux;
    }
    
    
    /**
     * Stream input.
     *
     * \param  in                     input stream
     * \param  object                 uniform flux
     * \return                        input stream
     */
    friend inline std::istream& operator>>(std::istream& in, JFlatFlux& object)
    {
      in >> object.flux;

      return in;
    }
    
    
    /**
     * Write power-law neutrino fluxes to output stream.
     *
     * \param  out                    output stream
     * \param  object                 uniform
     * \return                        output stream
     */
    friend inline std::ostream& operator<<(std::ostream& out, const JFlatFlux& object)
    {
      const JFormat format(out);
      
      out << FIXED(5,3) << object.flux;
      
      return out;
    }
    
    double flux;    //!< flux         [GeV * m^-2 * sr^-1 * s^-1]
  };


  /**
   * Example function object for computing power-law flux.
   */
  struct JPowerLawFlux
  {
    /**
     * Default constructor.
     */
    JPowerLawFlux() :
      normalisation(1.0),
      spectralIndex(0.0)
    {}
    
    
    /**
     * Constructor.
     *
     * \param  normalisation         normalisation
     * \param  spectralIndex         spectral index
     */
    JPowerLawFlux(const double normalisation,
		  const double spectralIndex) :
      normalisation(normalisation),
      spectralIndex(spectralIndex)
    {}
    
    
    /**
     * Get flux of given event.
     *
     * \param  evt             event
     * \return                 flux         [GeV * m^-2 * sr^-1 * s^-1]
     */
    double operator()(const Evt& evt) const
    {
      using namespace std;
      using namespace JPP;

      if (has_neutrino(evt)) {

	const Trk& neutrino = get_neutrino(evt);
	
	return normalisation * pow(neutrino.E, -spectralIndex);

      } else {
	
	THROW(JNullPointerException, "JPowerLawFlux::operator(): No neutrino for event " << evt.id << '.' << endl);	
      }
    }
    
    
    /**
     * Stream input.
     *
     * \param  in                     input stream
     * \param  object                 power-law flux
     * \return                        input stream
     */
    inline friend std::istream& operator>>(std::istream&  in,
					   JPowerLawFlux& object)
    {
      return in >> object.normalisation
	        >> object.spectralIndex;
    }
    
    
    /**
     * Write power-law parameters to output stream.
     *
     * \param  out                    output stream
     * \param  object                 power-law flux
     * \return                        output stream
     */
    inline friend std::ostream& operator<<(std::ostream&        out,
					   const JPowerLawFlux& object)
    {
      const JFormat format(out);
      
      out << FIXED(5,3) << object.normalisation << ' '
	  << FIXED(5,3) << object.spectralIndex;

      return out;
    }
    
    
    double normalisation;       //!< normalisation      [GeV * m^-2 * sr^-1 * s^-1]
    double spectralIndex;       //!< spectral index     >= 0
  };
}


/**
 * \file
 * Example program for scanning event-weights of Monte Carlo files\n
 * containing a given set of primaries.
 *
 * The list of possible options for the flux includes:
 * <pre>
 *    -@ zero      \<type\>
 *    -@ flat      \<type\>  \<value\>
 *    -@ powerlaw  \<type\>  \<normalisation\>  \<spectral index\>
 * </pre>
 *
 * \author bjung
 */
int main(int argc, char **argv)
{
  using namespace std;
  using namespace JPP;

  JMultipleFileScanner_t               inputFiles;

  vector<int>                          zeroFluxes;
  map<int, JFlatFlux>                  flatFluxes;
  map<int, JPowerLawFlux>              powerlawFluxes;

  int                                  debug;

  try {

    JProperties fluxMaps;

    fluxMaps["zero"]     = zeroFluxes;
    fluxMaps["flat"]     = flatFluxes;
    fluxMaps["powerlaw"] = powerlawFluxes;
    
    JParser<> zap;
    
    zap['f'] = make_field(inputFiles);
    zap['@'] = make_field(fluxMaps)           = JPARSER::initialised();
    zap['d'] = make_field(debug)              = 1;

    zap(argc, argv);
  }
  catch(const exception& error) {
    FATAL(error.what() << endl);
  }

  // Sanity checks

  for (map<int, JPowerLawFlux>::const_iterator i = powerlawFluxes.cbegin(); i != powerlawFluxes.cend(); ++i) {
    if (abs(i->first) != TRACK_TYPE_NUE  &&
	abs(i->first) != TRACK_TYPE_NUMU &&
	abs(i->first) != TRACK_TYPE_NUTAU) {
      FATAL("Particle type " << i->first << " does not correspond to a neutrino." << endl);
    }
  }  

  // Create multi-particle flux function

  JFluxMultiParticle multiFlux;  
  
  for (vector<int>::const_iterator i = zeroFluxes.cbegin(); i != zeroFluxes.cend(); ++i) {
    multiFlux.insert(*i, make_fluxFunction(zeroFlux));
  }

  for (map<int, JFlatFlux>::const_iterator i = flatFluxes.cbegin(); i != flatFluxes.cend(); ++i) {
    multiFlux.insert(i->first, make_fluxFunction(i->second));
  }

  for (map<int, JPowerLawFlux>::const_iterator i = powerlawFluxes.cbegin(); i != powerlawFluxes.cend(); ++i) {
    multiFlux.insert(i->first, make_fluxFunction(i->second));
  }

  
  // Set event weighter
  
  JEvtWeightFileScannerSet<> scanners(inputFiles);

  const size_t n = scanners.setFlux(multiFlux);

  if (n == 0) {
    WARNING("No file found containing all given primaries; Flux function not set." << endl);
  }
  
  
  // Scan events
  
  for (JEvtWeightFileScannerSet<>::iterator scanner = scanners.begin(); scanner != scanners.end(); ++scanner) {
    
    if (scanner->simul.size() > 0) {
      STATUS("Scanning " << scanner->simul[0].program << " files..." << endl);
    }

    STATUS(LEFT(15) << "event" << RIGHT(15) << "weight" << endl);
    
    while (scanner->hasNext()) {
      
      const Evt*   event  = scanner->next();
      const double weight = scanner->getWeight(*event);
      
      STATUS(LEFT      (15)    << scanner->getCounter() <<
	     SCIENTIFIC(15, 3) << weight << '\r'); DEBUG(endl);
    }
  }

  return 0;
}