#ifndef __UWEVENT_HH__
#define __UWEVENT_HH__
#include <iostream>
#include <sstream>
#include <vector>
#include "fastjet/PseudoJet.hh"


/// very crude routine for reading from UW format
//  $Id: UWEvent.hh 1735 2010-07-05 19:32:41Z salam $
///
/// Main event particles are stored in event;
///
/// "internal" particles (those with lines starting -1) are stored
/// in internal_particles
///
/// The routine returns false if it reaches the end of the file
///
/// Since the storage format is px,py,pz,E, the routine checks 
/// particle masses and if < 0, resets them = 0 by rescaling the
/// energy.
///
/// The particle user indices are set to the particle pdg_id
bool readUWEvent(std::istream & istr, 
		 std::vector<fastjet::PseudoJet> & event,\
		 std::vector<fastjet::PseudoJet> & internal_particles
		 ) {
  event.resize(0);
  internal_particles.resize(0);

  int ipart, pdgid;
  double px, py, pz, E;
  bool started = false;
  std::string line;

  while (getline(istr, line)) {
    // ignore blank lines and comment lines
    if (line.length() == 0 || line[0] == '#') continue;

    // now convert the line to numbers
    std::istringstream sstr(line.c_str());
    sstr >> ipart >> px >> py >> pz >> E >> pdgid;

    // signal a new event
    if (ipart == 0) {
      if (started) break;
      else continue;
    }

    started = true;

    // force particle masses > 0
    double pvec2 = px*px + py*py + pz*pz;
    if (E*E < pvec2) E = sqrt(pvec2);
    fastjet::PseudoJet particle(px, py, pz, E);
    particle.set_user_index(pdgid);

    if (ipart > 0) {
      // a final-state particle
      event.push_back(particle);
    } else { // ipart < 0
      internal_particles.push_back(particle);
    }
  }
  return (event.size() > 0);
}

/// routine for reading in UW events that provides the main event
/// but not the "internal" particles
bool readUWEvent(std::istream & istr, std::vector<fastjet::PseudoJet> & event) {
  std::vector<fastjet::PseudoJet> internal_particles;
  return readUWEvent(istr, event, internal_particles);
}

#endif // __UWEVENT_HH__