#include <iostream>
#include <memory>

#include "TCanvas.h"
#include "TString.h"

#include "RooAddPdf.h"
#include "RooArgSet.h"
#include "RooDataSet.h"
#include "RooExponential.h"
#include "RooGaussian.h"
#include "RooPlot.h"
#include "RooRealVar.h"

using namespace RooFit;

void test_fit2()
{
   RooRealVar x("x", "x", 0., 200., "MeV");
   RooRealVar mean("mean", "mean", 100., 50., 150., "MeV");
   RooRealVar width("width", "width", 15., 1., 50., "MeV");

   RooGaussian sig_gauss("sig_gauss", "sig_gauss", x, mean, width);

   RooRealVar b("b", "b", -0.01, -1., 0., "");

   RooExponential bkg("bkg_pwrlaw_passed", "bkg_pwrlaw_passed", x, b);

   RooRealVar f("f", "f", 0.4, 0., 1., "");
   RooAddPdf model("model", "model", sig_gauss, bkg, f);

   std::unique_ptr<RooDataSet> dataset(model.generate(x, 1000000));

   mean.setVal(110.);
   width.setVal(20.);
   b.setVal(-0.001);
   f.setVal(0.5);

   model.fitTo(*dataset, Strategy(2), Minimizer("Minuit", "minimize"), Offset(true));

   TCanvas c("c", "c", 960, 720);

   std::unique_ptr<RooPlot> frame_passed(x.frame());
   dataset->plotOn(frame_passed.get());
   model.plotOn(frame_passed.get());
   frame_passed->Draw();

   c.SaveAs("./test2.pdf");

   return;
}