#!/usr/bin/python
# -*- coding: utf-8 -*-
from ROOT import *
gROOT.SetBatch()
gSystem.Load("libRooFit")
c1 = TCanvas("c1","c1",0,0,400,400)
c1.cd()

ct   = RooRealVar('ct','ct',  -10,100)

ctau1 = RooRealVar('ctau','ctau in fermi', 32)
ctau0 = RooRealVar('ctau','ctau in fermi', 5)
tm =  RooTruthModel("tm","truth model",ct)

decay1 = RooDecay('decay1','decay x delta', ct, ctau1, tm, RooDecay.SingleSided)
decay0 = RooDecay('decay0','decay x delta', ct, ctau0, tm, RooDecay.SingleSided)

sigfrac = RooRealVar("sigfrac","fraction of signal",0.7, 0.69, 0.71)  
model   = RooAddPdf("model","signal(decay1) + bkg(decay0)", decay1, decay0, sigfrac)
model.Print()

gen = model.generate(RooArgSet(ct), 1000)

model.fitTo(gen)
xframe = ct.frame()
gen.plotOn(xframe)
model.plotOn(xframe)
argset = RooArgSet(decay1)
model.plotOn(xframe, RooFit.Components(argset),  RooFit.LineColor(2))
xframe.Draw()
c1.SetLogy()
c1.SaveAs('proj_1.png')