// This shows that, the model-to-data normalization in x plot is wrong if a y fit range
// is applied in fit, regardless of the value of the range; is it a bug?
//
// In the plots, red line is with NormRange(), blue line is without.

using namespace RooFit;
RooWorkspace w("w",kTRUE);

void fit_normalization() {

  // Create 2D model with observables x and y. Apply a fit range "fit_range" on y.
  w.factory("x[0,10]");
  w.factory("y[1,9]");
  w::y.setRange("fit_range",5,6);  // setting any range is the same -- always wrong

  // Test model 1 : v5.28 cannot plot this model; v5.26 can if NormRange() is used.
  w.factory("Gaussian::model1(x,y,g_sigma[1,0.5,2])");
  plot(w::model1);

  // Test model 2 : G(x)*G(y) : both v5.28 and v5.26 cannot plot this
  w.factory("PROD::model2(Gaussian::g1(x,g1_mean[5],g1_sigma[1,0.5,2]),Gaussian::g2(y,g2_mean[5],g2_sigma[1,0.5,2]))");
  plot(w::model2);
}

void plot(RooAbsPdf& model) {

  TString model_name = model.GetName();

  data = model.generate(RooArgSet(w::x,w::y),50000);

  // Fit without fit_range
  model.fitTo(*data);

  x_frame = w::x.frame(Title(model_name+" full fit"));
  data->plotOn(x_frame);
  model.plotOn(x_frame);
  can=new TCanvas(); x_frame->Draw();

  // Fit with fit_range
  model.fitTo(*data, Range("fit_range"));

  // Not using ProjectionRange
  x_frame = w::x.frame(Title(model_name+" range fit without projection cut"));
  data->plotOn(x_frame);
  model.plotOn(x_frame);
  model.plotOn(x_frame,NormRange("fit_range"),LineColor(2));
  can=new TCanvas(); x_frame->Draw();

  // Use CutRange and ProjectionRange on fit_range
  x_frame = w::x.frame(Title(model_name+" range fit with CutRange() and ProjectionRange()"));
  data->plotOn(x_frame,CutRange("fit_range"));
  model.plotOn(x_frame,ProjectionRange("fit_range"));
  model.plotOn(x_frame,ProjectionRange("fit_range"),NormRange("fit_range"),LineColor(2));
  can=new TCanvas(); x_frame->Draw();

  // Try using Range() instead of ProjectionRange(); No use: Range() is only for the plot axis and has no effect on y axis.
//  x_frame = w::x.frame(Title(model_name+" range fit with CutRange() and Range()"));
//  data->plotOn(x_frame,CutRange("fit_range"));
//  model.plotOn(x_frame,Range("fit_range"));
//  model.plotOn(x_frame,Range("fit_range"),NormRange("fit_range"),LineColor(2));
//  can=new TCanvas(); x_frame->Draw();

}