#include "Fit/Fitter.h"
#include "Fit/BinData.h"
#include "Fit/Chi2FCN.h"
#include "TH1.h"
#include "TMath.h"
#include "Math/WrappedMultiTF1.h"
#include "HFitInterface.h"
#include "TCanvas.h"
#include "TRandom.h"

double Gauss(double *x, double *par)
{
  // par[0] is Offset
  // par[1] is Gaus-height
  // par[2] is Gaus-mean
  // par[3] is Gaus-sigma

  double fitval = par[0];
  double arg = 0;

  if (par[3] != 0) arg = (x[0] - par[2])/par[3];
  fitval += par[1]*TMath::Exp(-0.5*arg*arg);

  return fitval;
}


void UnbinnedFit() 
{
  unsigned int Max = 10000;
  vector<double> X;
  
  for (unsigned int i = 0; i < Max; ++i) {
    X.push_back(gRandom->Gaus(0, 1));
	}

	TH1D* Hist = new TH1D("Binned", "Binned", 100, -3, 3);
  for (double x: X) Hist->Fill(x);
  Hist->Draw();
  
	// Binned test instead
	// ROOT::Fit::BinData MaxData;
  // ROOT::Fit::FillData(MaxData, Hist);

	ROOT::Fit::UnBinData MaxData(X.size(), X.data());

  TF1* MaxFit = new TF1("Gauss", Gauss, -3, 3, 4);
  MaxFit->SetBit(kCanDelete);
  MaxFit->SetParNames("Offset", "Height", "Mean", "Sigma"); 
  MaxFit->SetParameters(0, 1, 0, 1); 
  
  ROOT::Math::WrappedMultiTF1 MaxFitFunction(*MaxFit, MaxFit->GetNdim());
  ROOT::Fit::Fitter MaxFitter;
  MaxFitter.SetFunction(MaxFitFunction, false);
  
  MaxFitter.Config().MinimizerOptions().SetPrintLevel(1);
  
  if (MaxFitter.Fit(MaxData) == true) {
  	ROOT::Fit::FitResult MaxResult = MaxFitter.Result();
  	MaxFit->SetFitResult(MaxResult);
  	MaxFit->Draw("SAME");
  }
  
  return;
}