//
// ********************************************************************
// * License and Disclaimer                                           *
// *                                                                  *
// * The  Geant4 software  is  copyright of the Copyright Holders  of *
// * the Geant4 Collaboration.  It is provided  under  the terms  and *
// * conditions of the Geant4 Software License,  included in the file *
// * LICENSE and available at  http://cern.ch/geant4/license .  These *
// * include a list of copyright holders.                             *
// *                                                                  *
// * Neither the authors of this software system, nor their employing *
// * institutes,nor the agencies providing financial support for this *
// * work  make  any representation or  warranty, express or implied, *
// * regarding  this  software system or assume any liability for its *
// * use.  Please see the license in the file  LICENSE  and URL above *
// * for the full disclaimer and the limitation of liability.         *
// *                                                                  *
// * This  code  implementation is the result of  the  scientific and *
// * technical work of the GEANT4 collaboration.                      *
// * By using,  copying,  modifying or  distributing the software (or *
// * any work based  on the software)  you  agree  to acknowledge its *
// * use  in  resulting  scientific  publications,  and indicate your *
// * acceptance of all terms of the Geant4 Software license.          *
// ********************************************************************
//
// $Id$
//
/////////////////////////////////////////////////////////////////////////////////
//      Class Name:	G4AdjointSimManager.hh
//	Author:       	L. Desorgher
// 	Organisation: 	SpaceIT GmbH
//	Contract:	ESA contract 21435/08/NL/AT
// 	Customer:     	ESA/ESTEC
/////////////////////////////////////////////////////////////////////////////////
//
// CHANGE HISTORY
// --------------
//      ChangeHistory: 
//	 	-15-01-2007 creation by L. Desorgher
//		-March 2008 Redesigned as a non RunManager.  L. Desorgher
//		-01-11-2009 Add the possibility to use user defined run, event, tracking, stepping, 
//				and stacking actions during the adjoint tracking phase. L. Desorgher
//		
//				
//
//-------------------------------------------------------------
//	Documentation:
//		This class represents the Manager of an adjoint/reverse MC simulation. 
//		An adjoint run is divided in a serie of alternative adjoint and forward tracking 
//		of adjoint and normal particles.
//
//		Reverse tracking phase:
//		-----------------------
//		An adjoint particle of a given type  (adjoint_e-, adjoint_gamma,...) is first generated on the so called adjoint source
//		with a random energy (1/E distribution) and direction. The adjoint source is the 
//		external surface of a user defined volume or of a user defined sphere. The adjoint
//		source should contain one or several sensitive volumes and should be small 
//		compared to the entire geometry.
//		The user can set the min and max energy of the adjoint source. After its
//		generation the adjoint primary  particle is tracked 
//		bacward in the geometry till a user  defined external surface (spherical or boundary of a volume)
//		or is killed before if it reaches a user defined  upper energy limit that represents
//		the maximum energy of the external source. During the reverse tracking, reverse
//		processes take place where  the adjoint particle being tracked can be either scattered
//		or transformed in another type of adjoint paticle. During the reverse tracking the
//		G4SimulationManager replaces the user defined Primary, Run, ... actions, by its own actions.
//		
//		Forward tracking phase
//		-----------------------
//		When an adjoint particle reaches the external surface its weight,type,  position, 
//		and directions are registered and a  normal primary particle with a type equivalent to the last generated primary adjoint is
//		generated with the same energy, position but opposite direction  and is  tracked normally in the sensitive region as in a fwd MC simulation. 
//		During this forward tracking phase the  
//		event, stacking, stepping, tracking actions defined by the user for its general fwd application are used. By this clear separation between
//		adjoint and fwd tracking phases , the code of the user developed for a fwd simulation should be only slightly modified to adapt it for an adjoint 
//		simulation. Indeed  the computation of the signal is done by the same actions or classes that the one used in the fwd simulation mode.  
// 
//		Modification to brought in a existing G4 application to use the ReverseMC method
//		-------------------------------
//		In order to be able to use the ReverseMC method in his simulation, the user should modify its code as such:
//			1) Adapt its physics list to use ReverseProcesses for adjoint particles. An example of such physics list is provided in an extended 
//			  example. 
//			2) Create an instance of    G4AdjointSimManager somewhere in the main code.
//			3) Modify the analysis part of the code to normalise the signal computed during the fwd phase to the weight of the last adjoint particle
//			 that reaches the external surface. This is done by using the following method of G4AdjointSimManager.
//					 
//					 G4int GetIDOfLastAdjParticleReachingExtSource()				     
//    					 G4ThreeVector GetPositionAtEndOfLastAdjointTrack(){ return last_pos;}
//					 G4ThreeVector GetDirectionAtEndOfLastAdjointTrack(){ return last_direction;}
//					 G4double GetEkinAtEndOfLastAdjointTrack(){ return last_ekin;} 
//					 G4double GetEkinNucAtEndOfLastAdjointTrack(){ return last_ekin_nuc;}
//					 G4double GetWeightAtEndOfLastAdjointTrack(){return last_weight;}
//   					 G4double GetCosthAtEndOfLastAdjointTrack(){return last_cos_th;}
//   					 G4String GetFwdParticleNameAtEndOfLastAdjointTrack(){return last_fwd_part_name;}
//   					 G4int GetFwdParticlePDGEncodingAtEndOfLastAdjointTrack(){return last_fwd_part_PDGEncoding;}
//   					 G4int GetFwdParticleIndexAtEndOfLastAdjointTrack().
//
//			  In orther to have a code working for both forward and adjoint simulation mode, the extra code needed in user actions for the adjoint
//			  simulation mode can be seperated to the code needed only for the normal forward  simulation by using the following method
//			             
//					G4bool GetAdjointSimMode() that return true if   an adjoint simulation is running and false if not!
//				  
//		          Example of modification in the analysis part of the code:
//			 -------------------------------------------------------------
//				Let say that in the forward simulation a G4 application computes the energy deposited in a volume.
//				The user wants to normalise its results for an external isotropic source of e- with differential spectrum given by f(E).
//				A possible modification of the code where the deposited energy Edep during an event  is registered would be the following  
//					
//  				G4AdjointSimManager* theAdjSimManager =    G4AdjointSimManager::GetInstance();	
//				if (theAdjSimManager->GetAdjointSimMode()) {
//					//code of the user that should be consider only for forwrad simulation
//					G4double normalised_edep = 0.;
//					if (theAdjSimManager->GetFwdParticleNameAtEndOfLastAdjointTrack() == "e-"){
//						G4double ekin_prim = theAdjSimManager->GetEkinAtEndOfLastAdjointTrack();
//						G4double weight_prim = theAdjSimManager->GetWeightAtEndOfLastAdjointTrack();
//						normalised_edep = weight_prim*f(ekin_prim);
//					} 
//					//then follow the code where normalised_edep is printed, or registered or whatever ....
//				}	
//				
//				else { //code of the user that should be consider only for forward simulation
//				}
//				Note that in this example a normalisation to only primary e- with only one spectrum f(E) is considered. The example code could be easily
//				adapted for a normalisatin to several spectra and several type of primary particles  in the same simulation. 
//

#ifndef G4AdjointSimManager_h
#define G4AdjointSimManager_h 1
#include "globals.hh"
#include "G4ThreeVector.hh"
#include <vector>


class G4UserEventAction;
class G4VUserPrimaryGeneratorAction;
class G4UserTrackingAction;
class G4UserSteppingAction;
class G4UserStackingAction;
class G4UserRunAction;
class G4AdjointRunAction;
class G4AdjointPrimaryGeneratorAction;
class G4AdjointSteppingAction;
class G4AdjointEventAction;
class G4AdjointStackingAction;
class G4ParticleDefinition;
class G4AdjointSimMessenger;
class G4PhysicsLogVector;

class G4AdjointSimManager  
{
  public:
    
    static G4AdjointSimManager* GetInstance();

  public: //publich methods
    
    void RunAdjointSimulation(G4int nb_evt);
    
    inline G4int GetNbEvtOfLastRun(){return nb_evt_of_last_run;}
    
    void SetAdjointTrackingMode(G4bool aBool);
    inline G4bool GetAdjointTrackingMode(){return  adjoint_tracking_mode;} //true if an adjoint track is being processed
    inline G4bool GetAdjointSimMode(){return  adjoint_sim_mode;} //true if an adjoint simulation is running

    G4bool GetDidAdjParticleReachTheExtSource();
    void RegisterAtEndOfAdjointTrack();
    void RegisterAdjointPrimaryWeight(G4double aWeight);

    inline G4int GetIDOfLastAdjParticleReachingExtSource(){return ID_of_last_particle_that_reach_the_ext_source;}; 				     
    inline G4ThreeVector GetPositionAtEndOfLastAdjointTrack(){ return last_pos;}
    inline G4ThreeVector GetDirectionAtEndOfLastAdjointTrack(){ return last_direction;}
    inline G4double GetEkinAtEndOfLastAdjointTrack(){ return last_ekin;} 
    inline G4double GetEkinNucAtEndOfLastAdjointTrack(){ return last_ekin_nuc;}
    inline G4double GetWeightAtEndOfLastAdjointTrack(){return last_weight;}
    inline G4double GetCosthAtEndOfLastAdjointTrack(){return last_cos_th;}
    inline const G4String& GetFwdParticleNameAtEndOfLastAdjointTrack(){return last_fwd_part_name;}
    inline G4int GetFwdParticlePDGEncodingAtEndOfLastAdjointTrack(){return last_fwd_part_PDGEncoding;}
    inline G4int GetFwdParticleIndexAtEndOfLastAdjointTrack(){return last_fwd_part_index;}
    
    std::vector<G4ParticleDefinition*> GetListOfPrimaryFwdParticles();
     
    G4bool DefineSphericalExtSource(G4double radius, G4ThreeVector pos);
    G4bool DefineSphericalExtSourceWithCentreAtTheCentreOfAVolume(G4double radius, const G4String& volume_name);
    G4bool DefineExtSourceOnTheExtSurfaceOfAVolume(const G4String& volume_name);
    void SetExtSourceEmax(G4double Emax);
    
    //Definition of adjoint source
    //---------------------------- 
     
    G4bool DefineSphericalAdjointSource(G4double radius, G4ThreeVector pos);
    G4bool DefineSphericalAdjointSourceWithCentreAtTheCentreOfAVolume(G4double radius, const G4String& volume_name);
    G4bool DefineAdjointSourceOnTheExtSurfaceOfAVolume(const G4String& volume_name);
    void SetAdjointSourceEmin(G4double Emin);
    void SetAdjointSourceEmax(G4double Emax);
    inline G4double GetAdjointSourceArea(){return area_of_the_adjoint_source;} 
    void ConsiderParticleAsPrimary(const G4String& particle_name);
    void NeglectParticleAsPrimary(const G4String& particle_name);
    void SetPrimaryIon(G4ParticleDefinition* adjointIon, G4ParticleDefinition* fwdIon);
    const G4String& GetPrimaryIonName();
    
    inline void SetNormalisationMode(G4int n){normalisation_mode=n;};
    G4int GetNormalisationMode(){return normalisation_mode;};
    G4double GetNumberNucleonsInIon(){return nb_nuc;};

    //Definition of user actions for the adjoint tracking phase
    //---------------------------- 
    void SetAdjointEventAction(G4UserEventAction* anAction);
    void SetAdjointSteppingAction(G4UserSteppingAction* anAction);
    void SetAdjointStackingAction(G4UserStackingAction* anAction);
    void SetAdjointTrackingAction(G4UserTrackingAction* anAction);
    void SetAdjointRunAction(G4UserRunAction* anAction); 
    
    //Set methods for user run actions
    //--------------------------------
    inline void UseUserStackingActionInFwdTrackingPhase(G4bool aBool){use_user_StackingAction=aBool;}

    //Convergence test
    //-----------------------
   /*
    void RegisterSignalForConvergenceTest(G4double aSignal);
    void DefineExponentialPrimarySpectrumForConvergenceTest(G4ParticleDefinition* aPartDef, G4double E0);
    void DefinePowerLawPrimarySpectrumForConvergenceTest(G4ParticleDefinition* aPartDef, G4double alpha);
     
   */ 

  private: 
  
    static G4AdjointSimManager* instance;
  
  private: // methods
    
    void SetRestOfAdjointActions(); 
    void SetAdjointPrimaryRunAndStackingActions();
    void ResetRestOfUserActions(); 
    void ResetUserPrimaryRunAndStackingActions(); 
    void DefineUserActions();

  private: //constructor and destructor
  
    G4AdjointSimManager();
   ~G4AdjointSimManager();

  private ://attributes
  
  //Messenger
  //----------
    G4AdjointSimMessenger* theMessenger;
  
  //user defined actions for the normal fwd simulation. Taken from the G4RunManager
  //-------------------------------------------------
    bool user_action_already_defined;
    G4UserRunAction*		fUserRunAction;
    G4UserEventAction*		fUserEventAction;
    G4VUserPrimaryGeneratorAction*	fUserPrimaryGeneratorAction;
    G4UserTrackingAction*	fUserTrackingAction;
    G4UserSteppingAction*	fUserSteppingAction;
    G4UserStackingAction*	fUserStackingAction;
    bool use_user_StackingAction; //only for fwd part of the adjoint simulation
    
  //action for adjoint simulation
  //-----------------------------
    G4UserRunAction*		theAdjointRunAction;
    G4UserEventAction*		theAdjointEventAction;
    G4AdjointPrimaryGeneratorAction* theAdjointPrimaryGeneratorAction;
    G4UserTrackingAction*	theAdjointTrackingAction;
    G4AdjointSteppingAction*	theAdjointSteppingAction;
    G4AdjointStackingAction*    theAdjointStackingAction;
      
  //adjoint mode
  //-------------
    G4bool adjoint_tracking_mode;
    G4bool adjoint_sim_mode;   

  //adjoint particle information on the external surface
  //----------------------------- 
    G4ThreeVector last_pos;
    G4ThreeVector last_direction;
    G4double last_ekin,last_ekin_nuc; //last_ekin_nuc=last_ekin/nuc, nuc is 1 if not a nucleus
    G4double last_cos_th;
    G4String last_fwd_part_name;
    G4int  last_fwd_part_PDGEncoding;
    G4int  last_fwd_part_index;
    G4double last_weight;
    G4int ID_of_last_particle_that_reach_the_ext_source;
      
    G4int nb_evt_of_last_run;
    G4int normalisation_mode;
     
  //Adjoint source
  //--------------
    G4double area_of_the_adjoint_source; 
    G4double nb_nuc;
    G4double theAdjointPrimaryWeight;

    //Weight Analysis
    //----------
    G4PhysicsLogVector* electron_last_weight_vector;
    G4PhysicsLogVector* proton_last_weight_vector;
    G4PhysicsLogVector* gamma_last_weight_vector;
    
    G4bool welcome_message;
    
/* For the future    
    //Convergence test
    //----------------
      
     G4double normalised_signal;
     G4double error_signal;
     G4bool convergence_test_is_used;
     G4bool power_law_spectrum_for_convergence_test; // true  PowerLaw, ;
     G4ParticleDefinition* the_par_def_for_convergence_test;
*/     
 
};

#endif