#include <cstdlib>
#include <iostream>
#include <map>
#include <string>
#include <list>
#include <math.h>
#include <tuple>

#include "TChain.h"
#include "TFile.h"
#include "TTree.h"
#include "TString.h"
#include "TObjString.h"
#include "TSystem.h"
#include "TROOT.h"
#include "TCanvas.h"
 
#include "RooRealVar.h"
#include "RooConstVar.h"
#include "RooGaussian.h"
#include "RooArgusBG.h"
#include "RooAddPdf.h"
#include "RooDataSet.h"
#include "RooPlot.h"

using namespace RooFit;
 
 
void tester() {
 
     // Declare observable
     RooRealVar x("x","x",-10,10) ;
     // Construction a gaussian pdf
     RooRealVar mean1("mean1","mean1",-2.0,-2.0,-2.0);
     RooRealVar mean2("mean2","mean2", 2.0, 2.0, 2.0);
     RooRealVar sigma1("sigma1","sigma1",1.0,1.0,1.0);
     RooRealVar sigma2("sigma2","sigma2",1.0,1.0,1.0);
  
     RooGaussian gauss1("gauss1","gauss1",x,mean1,sigma1);
     RooGaussian gauss2("gauss2","gauss2",x,mean2,sigma2);
  
     // Sampling events
     RooDataSet* data1 = gauss1.generate(x,1000);
     RooDataSet* data2 = gauss2.generate(x,1000);
  
     TCanvas* a = new TCanvas("a");
     a->cd();
     RooPlot* plot = x.frame();
     data1->plotOn(plot);
     data2->plotOn(plot);
     plot->SetTitle("raw data");
     plot->Draw();
  
     RooRealVar scale("scale","scale",0.1,0.0,100.);
  
     // Defining the varset
     RooArgSet varsetWithWeight(x, scale);
  
     // Make a master RooDataSet to add the intermediate ones to
     RooDataSet ds_global_MC("ds_global_MC", "ds_global_MC", varsetWithWeight, WeightVar(scale));
     ds_global_MC.Print("V");

     // Not a loop, but doing exactly what the loop code would have done
     // "Loop" 1
     std::cout << "\n\nFirst dataset:" << std::endl;
     scale.setVal(0.);
     RooDataSet* ds_local_MC1 = new RooDataSet("k", "k", varsetWithWeight, Import(*data1), WeightVar(scale));
  
     RooRealVar* w1 = (RooRealVar*) ds_local_MC1->addColumn(scale);
     std::cout << "After appending weight column:" << std::endl;
     ds_local_MC1->Print("V");

     ds_global_MC.append(*ds_local_MC1);
     std::cout <<"\nGlobal DS is:" << std::endl;
     ds_global_MC.get(0);
     ds_global_MC.Print("V");
     std::cout << "Weight is " << ds_global_MC.weight() << std::endl;
     
     // "Loop" 2
     std::cout << "\n\nSecond dataset:" << std::endl;
     scale.setVal(1.);
     RooDataSet* ds_local_MC2 = new RooDataSet("k", "k", varsetWithWeight, Import(*data2), WeightVar(scale));
  
     RooRealVar* w2 = (RooRealVar*) ds_local_MC2->addColumn(scale);
     ds_global_MC.append(*ds_local_MC2);
     std::cout <<"\nGlobal DS is:" << std::endl;
     ds_global_MC.get(1001);
     ds_global_MC.Print("V");
     std::cout << "Weight is " << ds_global_MC.weight() << std::endl;
  
     // Making the final dataset

 
     TCanvas* b = new TCanvas("b");
     b->cd();
 
     RooPlot* plot2 = x.frame();
     ds_global_MC.plotOn(plot2);
     plot2->SetTitle("attempted scaled data");
     plot2->Draw();
 
  }