#include <TROOT.h>
#include <TCanvas.h>
#include <THStack.h>

#include <ROOT/RDataFrame.hxx>

#include <sstream>

void looptest()
{
  ROOT::EnableImplicitMT();
  
  // Create some initial data
  size_t npoints = 10000000;
  ROOT::RDataFrame tdf(npoints);

  auto pidf = tdf.Define("x", "gRandom->Uniform(-1.0, 1.0)");
  // The following is tedious
    // .Define("x0","pow(x,0)")
    // .Define("x1","pow(x,1)")
    // .Define("x2","pow(x,2)")
    // .Define("x3","pow(x,3)")
    // .Define("x4","pow(x,4)");

  // Create values in a loop
  std::stringstream ss_name;
  std::stringstream ss_func;
  for(uint i=0;i<5;i++)
    {
      ss_name.str("");
      ss_name << "x" << i;

      ss_func.str("");
      ss_func << "pow(x," << i << ")";

      pidf=pidf.Define(ss_name.str(), ss_func.str());
    }

  // Apply selection
  auto seldf = pidf.Filter("x>0");

  // Plot the different branches
  TCanvas c;
  THStack hs;

  for(uint i=0;i<5;i++)
    {
      ss_name.str("");
      ss_name << "x" << i;

      auto myHisto = seldf.Histo1D({"","",50,0,1},ss_name.str());
      hs.Add(static_cast<TH1D*>(myHisto->Clone()));
    }

  hs.Draw("nostack");
  c.SaveAs("test.pdf");
   
}