#include <cmath>	// for the function 'exp()'

#include "LGSteppingAction.hh"
#include "LGDetectorConstruction.hh"
#include "LGEventAction.hh"

#include "G4StepStatus.hh"
#include "G4Track.hh"
#include "G4Step.hh"
#include "G4ios.hh"
#include "G4ParticleDefinition.hh"
#include "G4Navigator.hh" 

#include "Randomize.hh"

// parametrization of the quantum efficiency of the FEU-84-3 PMT tube
// as polynomial order 5
#define A  -2545.6
#define B  27.133
#define C -0.11521
#define D 2.45206E-04
#define E -2.60431E-07
#define F 1.09761E-10

G4int old=0;
G4int cnt=0;

G4ThreeVector photon_dir;
G4ThreeVector photon_pos;
G4ThreeVector photon_pos1;
G4int flag1 = 0;
G4int flag2 = 0;
G4int flag3 = 0;
G4int flag4 = 0;
G4int tid = 0;

LGSteppingAction::LGSteppingAction(LGEventAction* event_Act, G4double zLG, 
				   G4int qeff, TH1F **hist, TH2F **hist2d, G4int BendFirst )
  : event_Action(event_Act), zGlass(zLG), QE(qeff), Spec(hist), Spec2d(hist2d), LGBendFirst(BendFirst){}

LGSteppingAction::~LGSteppingAction() {;}

void LGSteppingAction::UserSteppingAction(const G4Step* aStep)
{
  //-------- 1. Get pre-step and post-step pointers
  G4StepPoint* pre_Step = aStep->GetPreStepPoint();
  G4TouchableHandle pre_TouchHandle = pre_Step->GetTouchableHandle();
  G4VPhysicalVolume* pre_Volume = pre_TouchHandle->GetVolume();
  
  G4StepPoint* post_Step = aStep->GetPostStepPoint();
  G4TouchableHandle post_TouchHandle = post_Step->GetTouchableHandle();
  G4VPhysicalVolume* post_Volume = post_TouchHandle->GetVolume();
  
  // primary particle stopped! => photon got absorbed
  if ((aStep->GetTrack()->GetTrackID()== 1)&&
      (aStep->GetTrack()->GetTrackStatus()!=fAlive)){
  }
  
  // get impact angle of photon on lead glass-PMT interace surface
  //if (aStep->GetTrack()->GetDefinition()->GetParticleName()=="opticalphoton"){
  //}
  
  G4bool VolumeTest = (pre_Volume != NULL) && (post_Volume != NULL);

  // 2. Check if the photon enters the light guide

  if (VolumeTest) {
    G4String particle_Name = 
      aStep->GetTrack()->GetDefinition()->GetParticleName();      

    //G4cout<<pre_Volume->GetName()<<"  "<<post_Volume->GetName()<<G4endl;
    
    // particle passed from scintillator to light guide
    if ( (pre_Volume->GetName() == "ScinBox") && (post_Volume->GetName() == "LGBox") ){
      if (particle_Name == "opticalphoton"){
	G4ThreeVector worldPos = post_Step->GetPosition();
	G4ThreeVector localPos = 
	  post_TouchHandle->GetHistory()->GetTopTransform().TransformPoint(worldPos);
	Spec2d[0]->Fill(localPos.x(),localPos.y());
      }
    }

    if (LGBendFirst){ // if the bending section of the light guide is first
      if ( (pre_Volume->GetName() == "LGBox") && (post_Volume->GetName() == "LGBendSection") ){
	if (particle_Name == "opticalphoton"){
	  G4ThreeVector worldPos = post_Step->GetPosition();
	  G4ThreeVector localPos = 
	    post_TouchHandle->GetHistory()->GetTopTransform().TransformPoint(worldPos);
	  Spec2d[1]->Fill(worldPos.x(),worldPos.y());
	}
      } 
      if ( (pre_Volume->GetName() == "LGBendSection") && (post_Volume->GetName() == "LGTappered") ){
	if (particle_Name == "opticalphoton"){
	  G4ThreeVector worldPos = post_Step->GetPosition();
	  G4ThreeVector localPos = 
	    post_TouchHandle->GetHistory()->GetTopTransform().TransformPoint(worldPos);
	  Spec2d[2]->Fill(localPos.x(),localPos.y());
	}
      } 
      if ( (pre_Volume->GetName() == "LGTappered") && (post_Volume->GetName() == "LGTub") ){
	if (particle_Name == "opticalphoton"){
	  G4ThreeVector worldPos = post_Step->GetPosition();
	  G4ThreeVector localPos = 
	    post_TouchHandle->GetHistory()->GetTopTransform().TransformPoint(worldPos);
	  Spec2d[3]->Fill(localPos.x(),localPos.y());
	}
      } 
    } else { // if the bending section of the light guide is after the tapered section
      if ( (pre_Volume->GetName() == "LGBox") && (post_Volume->GetName() == "LGTappered") ){
	if (particle_Name == "opticalphoton"){
	  G4ThreeVector worldPos = post_Step->GetPosition();
	  G4ThreeVector localPos = 
	    post_TouchHandle->GetHistory()->GetTopTransform().TransformPoint(worldPos);
	  Spec2d[1]->Fill(localPos.x(),localPos.y());
	}
      } 
      if ( (pre_Volume->GetName() == "LGTappered") && (post_Volume->GetName() == "LGBendSection") ){
	if (particle_Name == "opticalphoton"){
	  G4ThreeVector worldPos = post_Step->GetPosition();
	  G4ThreeVector localPos = 
	    post_TouchHandle->GetHistory()->GetTopTransform().TransformPoint(worldPos);
	  Spec2d[2]->Fill(worldPos.x(),worldPos.y());
	}
      } 
      if ( (pre_Volume->GetName() == "LGBendSection") && (post_Volume->GetName() == "LGTub") ){
	if (particle_Name == "opticalphoton"){
	  G4ThreeVector worldPos = post_Step->GetPosition();
	  G4ThreeVector localPos = 
	    post_TouchHandle->GetHistory()->GetTopTransform().TransformPoint(worldPos);
	  Spec2d[3]->Fill(localPos.x(),localPos.y());
	}
      } 
    }
    if ( (pre_Volume->GetName() == "LGTub") && (post_Volume->GetName() == "PMTGlass") ){
      if (particle_Name == "opticalphoton"){
	G4ThreeVector worldPos = post_Step->GetPosition();
	G4ThreeVector localPos = 
	  post_TouchHandle->GetHistory()->GetTopTransform().TransformPoint(worldPos);
	Spec2d[4]->Fill(localPos.x(),localPos.y());
      }
    } 
    if ( (pre_Volume->GetName() == "PMTGlass") && (post_Volume->GetName() == "PMTCathode") ) {
      if (particle_Name == "opticalphoton"){
	G4ThreeVector worldPos = post_Step->GetPosition();
	G4ThreeVector localPos = 
	  post_TouchHandle->GetHistory()->GetTopTransform().TransformPoint(worldPos);
	Spec2d[5]->Fill(localPos.x(),localPos.y());
      }
    }  
    
  }


}