#ifndef _BFIELD_PROP_H_
#define _BFIELD_PROP_H_

/***********************************************************************
**                                                                    **
**          /----------------------------------------------\          **
**         |  Delphes, a framework for the fast simulation  |         **
**         |       of a  generic collider experiment        |         **
**          \----------------------------------------------/          **
**                                                                    **
**                                                                    **
**   This package uses:                                               **
**   ------------------                                               **
**   FastJet algorithm: Phys. Lett. B641 (2006) [hep-ph/0512210]      ** 
**   Hector: JINST 2:P09005 (2007) [physics.acc-ph:0707.1198v2]       ** 
**   FROG: [hep-ex/0901.2718v1]                                       **
**                                                                    **
** ------------------------------------------------------------------ **
**                                                                    **
**   Main authors:                                                    **
**   -------------                                                    **
**                                                                    **
**                Severine Ovyn                Xavier Rouby           ** 
**          severine.ovyn@uclouvain.be      xavier.rouby@cern         ** 
**                                                                    ** 
**         Center for Particle Physics and Phenomenology (CP3)        ** 
**                Universite catholique de Louvain (UCL)              **       
**                     Louvain-la-Neuve, Belgium                      **            
**                                                                    **
**                      Copyright (C) 2008-2009,                      **
**                        All rights reserved.                        **  
**                                                                    **
***********************************************************************/

#include "TLorentzVector.h"
#include "SmearUtil.h"
#include "BlockClasses.h"
#include "TSimpleArray.h"

using namespace std;

class TrackPropagation {

 public:
  // Constructor
    TrackPropagation();
    TrackPropagation(const string& DetDatacard);
    TrackPropagation(const RESOLution * DetDatacard);
    TrackPropagation(const TrackPropagation & tp);
    TrackPropagation& operator=(const TrackPropagation & tp);
    ~TrackPropagation() {delete DET;};
    void init(); // for constructors

    // Propagation and bfield are very similar. At the end, after code cleaning,
    // only bfield will remain in this class 
    void Propagation(const TRootGenParticle *Part,TLorentzVector &genMomentum);
    void bfield(TRootGenParticle *Part); // fills in Part->EtaCalo and Part->PhiCalo


 private:
   unsigned int MAXITERATION;
   RESOLution *DET;


   /// radial/longitudinal extensions of magnetic field volume
   double R_max, z_max;
   /// magnetic field components
   double B_x, B_y, B_z;
   /// particle charge
   double q;
   /// initial coordinate
   double phi_0;
   /// relativistic gamma \times m
   double gammam;
   /// giration frequency and radius
   double omega, r;
   /// center of the helix in the transverse plane
   double x_c, y_c, R_c, Phi_c;
   // variable for an intermediate computing
   double rr;
   /// times for exiting the magnetic field volume
   double t, t_z, t_T;
   /// coordinates of the exit point
   double x_t, y_t, z_t, R_t, Phi_t, Theta_t, Eta_t;
   /// energy-momentum of the exit point [Gev] et c=1
   double Px_t, Py_t, Pz_t, PT_t, p_t, E_t;

   unsigned int loop_overflow_counter;
};
  
#endif