%%cpp -d
#include "RooRealVar.h"
#include "RooDataSet.h"
#include "RooGaussian.h"
#include "RooGaussModel.h"
#include "RooDecay.h"
#include "RooLandau.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<RooDataSet> data{decay_gm.generate(dt, ProtoData(*expDataDterr))};

decay_gm.fitTo(*data, ConditionalObservables(dterr), PrintLevel(-1));

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

RooPlot *frame = dt.frame(Title("Slices of decay(dt|dterr) at various dterr"));
for (Int_t ibin = 0; ibin < 100; ibin += 20) {
   dterr.setBin(ibin);
   decay_gm.plotOn(frame, Normalization(5.));
}

RooPlot *frame2 = dt.frame(Title("Projection of decay(dt|dterr) on dt"));
data->plotOn(frame2);

decay_gm.plotOn(frame2, ProjWData(*expDataDterr, true));

TCanvas *c = new TCanvas("rf306_condpereventerrors", "rf306_condperventerrors", 1200, 400);
c->Divide(3);
c->cd(1);
gPad->SetLeftMargin(0.20);
hh_decay->GetZaxis()->SetTitleOffset(2.5);
hh_decay->Draw("surf");
c->cd(2);
gPad->SetLeftMargin(0.15);
frame->GetYaxis()->SetTitleOffset(1.6);
frame->Draw();
c->cd(3);
gPad->SetLeftMargin(0.15);
frame2->GetYaxis()->SetTitleOffset(1.6);
frame2->Draw();

gROOT->GetListOfCanvases()->Draw()