// Author: David Lawrence  June 25, 2004
//
//
// hd_ana.cc
//

#include <iostream>
#include <iomanip>
#include <string>
using namespace std;

#include <stdlib.h>

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

#include <TFile.h>
#include <TTree.h>
#include <TVector3.h>
#include <TH2.h>

int Nr = 81;
int Nphi = 1;
int Nz = 401;

double Rmin = 1.0*2.54;
double Rmax = 81.0*2.54;

double Phimin = 0.0;
double Phimax = 0.0;

double Zmin = -126.0*2.54;
double Zmax = 274.0*2.54;
double Z0 = 0.0;

void Usage(void);
void ParseCommandLineArgs(int narg, char* argv[]);

//-----------
// main
//-----------
int main(int narg, char *argv[])
{

	// Parse command line arguments and then create a DApplication
	ParseCommandLineArgs(narg, argv);
	DApplication *dapp = new DApplication(narg, argv);
	dapp->Init();

	// open ROOT file
	float val[10];
	TFile* ROOTfile = new TFile("bfield.root","RECREATE","Produced by bfield2root");
	ROOTfile->SetCompressionLevel(6);
	cout<<"Opened ROOT file \"bfield.root\""<<endl;

	// Have Dapplication create Magnetic Field Map
	DMagneticFieldMap *bfield = dapp->GetBfield();

	// Create Tree
	TTree *tree = new TTree("Bfield","Magnetic Field");
	tree->Branch("B",val,"x/F:y:z:r:phi:Bx:By:Bz:Br:Bphi");
	
	// Loop over cylindrical grid and fill tree
	double r = Rmin;
	for(int ir=0; ir<Nr; ir++){
		if(Nr>1) r = Rmin + (double)ir*(Rmax-Rmin)/(double)(Nr-1);
		double phi = Phimin;
		for(int iphi=0; iphi<Nphi; iphi++){
			if(Nphi>1) phi = Phimin + (double)iphi*(Phimax-Phimin)/(double)(Nphi-1);
			double z = Zmin;
			for(int iz=0; iz<Nz; iz++){
				if(Nz>1) z = Zmin + (double)iz*(Zmax-Zmin)/(double)(Nz-1);
				
				double x = r*cos(phi);
				double y = r*sin(phi);
				
				double Bx, By, Bz;
				bfield->GetField(x, y, z-Z0, Bx, By, Bz);
				
				TVector3 B(Bx, By, Bz);
				double Br = B.Dot(TVector3(x, y, 0.0))/sqrt(x*x + y*y);
				double Bphi = atan2(By, Bx);
				
				val[0] = x;
				val[1] = y;
				val[2] = z;
				val[3] = r;
				val[4] = phi;
				val[5] = Bx;
				val[6] = By;
				val[7] = Bz;
				val[8] = Br;
				val[9] = Bphi;

				tree->Fill();
			}
		}	
	}
	
	// Create 2D histos in R and Z
	TH2D *Bz_vs_r_vs_z = new TH2D("Bz_vs_r_vs_z", "", 651, -25, 625.0, 200, 0.0, 100.0);
	Bz_vs_r_vs_z->SetXTitle("z (cm)");
	Bz_vs_r_vs_z->SetYTitle("r (cm)");
	Bz_vs_r_vs_z->SetStats(0);
	TH2D *Btot_vs_r_vs_z = (TH2D*)Bz_vs_r_vs_z->Clone("Btot_vs_r_vs_z");
	for(int ibin=1; ibin<=Bz_vs_r_vs_z->GetNbinsX(); ibin++){
		double z = Bz_vs_r_vs_z->GetXaxis()->GetBinCenter(ibin);
		for(int jbin=1; jbin<=Bz_vs_r_vs_z->GetNbinsY(); jbin++){
			double r = Bz_vs_r_vs_z->GetYaxis()->GetBinCenter(jbin);
			
			double Bx, By, Bz;
			bfield->GetField(r, 0.0, z-Z0, Bx, By, Bz);
			double Btot = sqrt(Bx*Bx + By*By + Bz*Bz);
			
			Bz_vs_r_vs_z->SetBinContent(ibin, jbin, Bz);
			Btot_vs_r_vs_z->SetBinContent(ibin, jbin, Btot);
		}
	}

	ROOTfile->Write();
	delete ROOTfile;
	cout<<endl<<"Closed ROOT file"<<endl;
		
	return 0;
}

//-----------------------
// Usage
//-----------------------
void Usage(void)
{
	cout<<endl;
	cout<<"Usage:"<<endl;
	cout<<"   bfield2root [options]"<<endl;
	cout<<endl;
	cout<<" options:"<<endl;
	cout<<"    -h, --help   Show this Usage statement"<<endl;
	cout<<"    -Nr     #    Set the number of grid points in R"<<endl;
	cout<<"    -Nphi   #    Set the number of grid points in Phi"<<endl;
	cout<<"    -Nz     #    Set the number of grid points in Z"<<endl;
	cout<<"    -Rmin   #    Set the minimum value for R (cm)"<<endl;
	cout<<"    -Rmax   #    Set the maximum value for R (cm)"<<endl;
	cout<<"    -Phimin #    Set the minimum value for Phi (radians)"<<endl;
	cout<<"    -Phimax #    Set the maximum value for Phi (radians)"<<endl;
	cout<<"    -Zmin   #    Set the minimum value for Z (cm)"<<endl;
	cout<<"    -Zmax   #    Set the maximum value for Z (cm)"<<endl;
	cout<<"    -Z0     #    Shift the map's z-coordinate"<<endl;
	cout<<endl;
	cout<<" The bfield to root program can be used to generate a ROOT TTree of the"<<endl;
	cout<<"magnetic field of the Hall-D solenoid. The field is read from the same source"<<endl;
	cout<<"as is used by the reconstruction and simulation programs. Since it is a DANA"<<endl;
	cout<<"based program, it accepts the same same arguments to manipulate the field as"<<endl;
	cout<<"other DANA programs. Namely, -PBFIELD_MAP=XXX and -PBFIELD_TYPE=YYY ."<<endl;
	cout<<endl;
	cout<<"For example:  -PBFIELD_MAP=Magnets/Solenoid/solenoid_1500"<<endl;
	cout<<endl;
	cout<<"The entries in the TTree are evaluated on a grid in cylindrical coordinates"<<endl;
	cout<<"that likely does not reflect the points in the underlying map. As such, the"<<endl;
	cout<<"values in the tree are a result of the interpolation of the underlying map's"<<endl;
	cout<<"points."<<endl;
	cout<<endl;

}

//-----------------------
// ParseCommandLineArgs
//-----------------------
void ParseCommandLineArgs(int narg, char* argv[])
{
	for(int i=1; i<narg; i++){
		string arg(argv[i]);
		string next(i<narg-1 ? argv[i+1]:"");
		float argf = atof(next.c_str());
		int   argi = atoi(next.c_str());
		bool used_next = false; // keep track if "next" is used so we can have a single error check below
		
		if(arg=="-Nr"){used_next=true; Nr = argi;}
		if(arg=="-Nphi"){used_next=true; Nphi = argi;}
		if(arg=="-Nz"){used_next=true; Nz = argi;}
		if(arg=="-Rmin"){used_next=true; Rmin = argf;}
		if(arg=="-Rmax"){used_next=true; Rmax = argf;}
		if(arg=="-Phimin"){used_next=true; Phimin = argf;}
		if(arg=="-Phimax"){used_next=true; Phimax = argf;}
		if(arg=="-Zmin"){used_next=true; Zmin = argf;}
		if(arg=="-Zmax"){used_next=true; Zmax = argf;}
		if(arg=="-Z0"){used_next=true; Z0 = argf;}
		
		if(arg=="-h" || arg=="--help"){Usage(); exit(0);}
		
		if(used_next){
			// skip to next argument
			i++;
			
			// If i is now > than narg, then no value was passed to an "-XXX" argument
			if(i>narg){
				_DBG_<<"No argument given for \""<<arg<<"\" argument!"<<endl;
				Usage();
				exit(-1);
			}
		}
	}
}