#include "RooRealVar.h"
#include "RooDataSet.h"
#include "RooGaussian.h"
#include "RooConstVar.h"
#include "RooPolynomial.h"
#include "RooLinearMorph.h"
#include "RooNLLVar.h"
#include "TCanvas.h"
#include "TAxis.h"
#include "RooPlot.h"
#include "TH1.h"

using namespace RooFit ;


void rooFit_Test(){

  TF1  *f1 = new TF1("f1","exp([0]*x)",2.4,3.5);
  TF1  *f2 = new TF1("f2","gaus",2.4,3.5);

  f1->SetParameter(0,2.0);

  f2->SetParameter(0,10);
  f2->SetParameter(1,2.8);
  f2->SetParameter(2,0.04);

  f1->Draw();
  //return;

  TH1D *H1 = new TH1D("H1","",100,2.3,3.5);
  TH1D *H2 = new TH1D("H2","",60,2.3,3.5);

  for(int i=0;i<20000;i++)   H1->Fill(f1->GetRandom());
  for(int i=0;i<2000;i++)    H1->Fill(f2->GetRandom());
  for(int i=0;i<500000;i++)  H2->Fill(f1->GetRandom());

  H2->Draw();

  //-------------------------------------------------------------------
  // At this point I have a generated background of the shape f1, and
  // a distribution which is a summ of f1 and f2 with lower statistics
  // So, let's RooFit-it !
  //-------------------------------------------------------------------


  RooRealVar  x("x","x",2.4,3.4);
  RooRealVar  mean("mean","mean",2.7,2.9);
  RooRealVar  sigma("sigma","sigma",0.0005,0.058);
  RooGaussian  gauss("gauss","Theta Peak",x,mean,sigma);

  RooDataHist bkgShape("simulation","",x,H2);
  
  RooHistPdf  BackGround("BackGround","Phi Simulation",x,bkgShape,7);

  RooRealVar  nsig("nsig","signal Fracktion",500,0.,100000.);
  RooRealVar  nbkg("nbkg","backgroun Fracktion",500,0.,100000.);

  RooAddPdf   fModel("Model","Model",RooArgList(BackGround,gauss),RooArgList(nbkg,nsig));



  RooPlot  *xframe = x.frame();

  RooDataHist data("data","",x,H1);  
  RooFitResult* res = fModel.fitTo(data,Range(2.4,3.4),Minos(kTRUE),PrintLevel(3),Save());

  data.plotOn(xframe);
  fModel.plotOn(xframe);
  //  BackGround.plotOn(xframe); // This line when uncommented does not plot the right fitted background
  //  gauss.plotOn(xframe); // Same with this !
  xframe->Draw();


  // -------------------------------------------------------------------------------------------------------------------------
  // So far so good, following the examples I was able to fit the generated distribution, but the problem starts here.
  // -----
  // At this point I would like to go over my sample histogram (H1) and evaluate the model, the background and the gaussian 
  // at every H1->BinCenter(1 to NbinsX), for my own calculations of significance 
  //
  // The values returned below do not add up to the statistical sample that I have.
  //-------

  x.setVal(2.8);

  cout << " Fitted Value     = " << fModel.getVal(x) << endl ;
  cout << " BackGround Value = " << BackGround.getVal(x) << endl ;
  cout << " Fitted Gauss     = " << gauss.getVal(x) << endl ;



}