#include "Fit/Fitter.h"
#include "Fit/BinData.h"
#include "Fit/Chi2FCN.h"
#include "TList.h"
#include "Math/WrappedMultiTF1.h"
#include "HFitInterface.h"
#include "TCanvas.h"
#include "TStyle.h"
#include "TGraphMultiErrors.h"
#include "TFitResult.h"

void GaussFit(TH1D* h1D, TF1* ffit);

void FitParScanNew()  {

   //ROOT::Fit::FitResult fit_results;

   auto h1 = new TH1D("h1","h1",100,-5,5);
   h1->FillRandom("gaus");

   TF1 * f1 = new TF1("f1","gaus", -5,5);

   GaussFit(h1, f1);

   

  

}
//___________________________________________________________________________________________________
void GaussFit(TH1D* h1D, TF1* ffit) { //Fit with ROOT::Fit method

	ROOT::Fit::DataOptions opt;
	ROOT::Fit::DataRange range;

	ROOT::Fit::BinData data(opt,range);
	ROOT::Fit::FillData(data, h1D);

	ROOT::Math::WrappedMultiTF1 fitfunc(*ffit,1);

	ROOT::Fit::Fitter fitter;
	fitter.SetFunction(fitfunc, false);

   fitter.Config().ParSettings(0).SetLimits(0,1.E6);
   fitter.Config().ParSettings(2).SetLowerLimit(0);

	ROOT::Math::MinimizerOptions(mopt);

   mopt.SetMinimizerType("Minuit2");

   mopt.SetPrintLevel(1);
	// print the default minimizer option values
	mopt.Print();
   fitter.Config().SetMinimizerOptions(mopt);
   fitter.Fit(data); // chi2 fit'

   const ROOT::Fit::FitResult & result = fitter.Result();

   result.Print(std::cout);


   ffit ->SetFitResult(result);
        

   h1D ->GetListOfFunctions()->Add(ffit);

   double pmin = result.Parameter(2) - 10*result.ParError(2);
   double pmax = result.Parameter(2) + 10*result.ParError(2);

  
 
   UInt_t iNoSteps = 50;
   TGraph * gr = new TGraph(iNoSteps);

   ((ROOT::Fit::FitResult &) result).Scan(2, iNoSteps, gr->GetX(), gr->GetY(), pmin,pmax);

   // for (int i = 0; i < gr->GetN(); i++)
   //    std::cout << gr->GetX()[i] << "  " << gr->GetY()[i] << std::endl;

   gr->Draw("AC");



   //return result;
}