%%cpp -d
#include "RooRealVar.h"
#include "RooDataSet.h"
#include "RooGaussian.h"
#include "RooGaussModel.h"
#include "RooDecay.h"
#include "RooLandau.h"
#include "RooProdPdf.h"
#include "RooHistPdf.h"
#include "RooPlot.h"
#include "TCanvas.h"
#include "TAxis.h"
#include "TH1.h"
using namespace RooFit;

RooRealVar dt("dt", "dt", -10, 10);
RooRealVar dterr("dterr", "per-event error on dt", 0.01, 10);

RooRealVar bias("bias", "bias", 0, -10, 10);
RooRealVar sigma("sigma", "per-event error scale factor", 1, 0.1, 10);
RooGaussModel gm("gm1", "gauss model scaled bt per-event error", dt, bias, sigma, dterr);

RooRealVar tau("tau", "tau", 1.548);
RooDecay decay_gm("decay_gm", "decay", dt, tau, gm, RooDecay::DoubleSided);

RooLandau pdfDtErr("pdfDtErr", "pdfDtErr", dterr, 1.0, 0.25);
std::unique_ptr<RooDataSet> expDataDterr{pdfDtErr.generate(dterr, 10000)};

std::unique_ptr<RooDataHist> expHistDterr{expDataDterr->binnedClone()};
RooHistPdf pdfErr("pdfErr", "pdfErr", dterr, *expHistDterr);

RooProdPdf model("model", "model", pdfErr, Conditional(decay_gm, dt));

std::unique_ptr<RooDataSet> data{model.generate({dt, dterr}, 10000)};

model.fitTo(*data, PrintLevel(-1));

TH1 *hh_model = model.createHistogram("hh_model", dt, Binning(50), YVar(dterr, Binning(50)));
hh_model->SetLineColor(kBlue);

RooPlot *frame = dt.frame(Title("Projection of model(dt|dterr) on dt"));
data->plotOn(frame);
model.plotOn(frame);

TCanvas *c = new TCanvas("rf307_fullpereventerrors", "rf307_fullperventerrors", 800, 400);
c->Divide(2);
c->cd(1);
gPad->SetLeftMargin(0.20);
hh_model->GetZaxis()->SetTitleOffset(2.5);
hh_model->Draw("surf");
c->cd(2);
gPad->SetLeftMargin(0.15);
frame->GetYaxis()->SetTitleOffset(1.6);
frame->Draw();

gROOT->GetListOfCanvases()->Draw()