#ifndef _CPPMAGNETICFIELD_
#define _CPPMAGNETICFIELD_

#include "G4MagneticField.hh"
#include "G4SystemOfUnits.hh"
#include "G4ThreeVector.hh"

// The following are used to work around a problem that ROOT defines
// sume functions named Info, Warning, and Error that conflict with 
// the enum values of the same names defiend in GEANT4. 
#define Info InfoXX
#define Warning WarningXX
#define Error ErrorXX

#include <DANA/DApplication.h>
#include <HDGEOMETRY/DMagneticFieldMap.h>

extern DApplication *dapp;
extern G4ThreeVector LAB_OFFSET; // Location of LASS volume in World volume. Used to translate to lab coordinates
extern string BFIELD_MAP; // Set in CPPsim.cc
extern int RUN_NUMBER;

class CPPMagneticField: public G4MagneticField{
	
public:

	//-----------------------
	// CPPMagneticField
	//-----------------------
	CPPMagneticField(){
		
		bfield = NULL;

		if( (BFIELD_MAP!="default") && (gPARMS!=NULL) ){
			gPARMS->SetDefaultParameter("BFIELD_MAP", BFIELD_MAP, "B-field map");
		}
		if(dapp) bfield = dapp->GetBfield(RUN_NUMBER);		
		if(!bfield){
			cout << "***** UNABLE TO CREATE DMagneticFieldMap ****" << endl;
			exit(-1);
		}else{
			cout << "DMagneticFieldMap created at: 0x" << hex << bfield << dec <<endl;
			
			extern CPPMagneticField *gCPPMagneticField;
			gCPPMagneticField = this;
		}
	}

	//-----------------------
	// ~CPPMagneticField
	//-----------------------
	virtual ~CPPMagneticField(){
	
	}
	
	//-----------------------
	// GetFieldValue
	//-----------------------
	void GetFieldValue(const double Point[4], double *Bfield) const{
	
		/// Routine is called by GEANT4 when tracking

		// Shift position into nominal GlueX lab coordinates and convert into cm
		double x = (Point[0] - LAB_OFFSET.x()) / cm;
		double y = (Point[1] - LAB_OFFSET.y()) / cm;
		double z = (Point[2] - LAB_OFFSET.z()) / cm;
		
		// Get field from HDGEOMETRY library
		bfield->GetField(x, y, z, Bfield[0], Bfield[1], Bfield[2]);
// printf("%s:%d B(%4.3f, %4.3f, %4.3f) = (%4.3f, %4.3f, %4.3f)\n", __FILE__, __LINE__, x, y, z, Bfield[0], Bfield[1], Bfield[2]);
		// B-field is returned in Tesla so convert to native units of GEANT4
		Bfield[0] *= tesla;
		Bfield[1] *= tesla;
		Bfield[2] *= tesla;
	}

	//-----------------------
	// GetFieldValue
	//-----------------------
	void GetFieldValue(const G4ThreeVector &pos, G4ThreeVector &B) const{
		// "pos" should be in global Geant4 coordinates (i.e. mm) withOUT
		// having subtracting the LAB_OFFSET (that is done internally)
		double Point[4] = {pos.x(), pos.y(), pos.z(), 0.0};
		double Bfield[3];
		GetFieldValue(Point, Bfield);
		B.set(Bfield[0], Bfield[1], Bfield[2]);
	}

private:
	DMagneticFieldMap *bfield;
};

extern CPPMagneticField *gCPPMagneticField;


#endif // _CPPMAGNETICFIELD_