/// \file
/// \ingroup tutorial_multicore
/// \notebook -draw
/// Fill histograms in parallel with automatic binning.
/// Illustrates use of power-of-two autobin algorithm
///
/// \macro_code
/// \macro_image
///
/// \date November 2017
/// \author Gerardo Ganis

// The number of workers
const UInt_t nWorkers = 8U;

// Reference boundaries
// const Double_t xmiref = -1.;
// const Double_t xmaref = 7.;

Int_t mt304_fillHistos(UInt_t nNumbers = 1001)
{

   // The first, fundamental operation to be performed in order to make ROOT
   // thread-aware.
   ROOT::EnableThreadSafety();

   // Histograms to be filled in parallel
//    ROOT::TThreadedObject<TH1D> h1d("h1d", "1D test histogram", 64, 0., -1.);
//    ROOT::TThreadedObject<TH1D> h1dr("h1dr", "1D test histogram w/ ref boundaries", 64, xmiref, xmaref);
   TH2Poly h0;
   TH2Poly h0r;
   h0.Honeycomb(-15,-10,1,20,20);
   h0r.Honeycomb(-15,-10,0.5,40,40);
   ROOT::TThreadedObject<TH2Poly> h1d(h0);
   ROOT::TThreadedObject<TH2Poly> h1dr(h0r);

   RooWorkspace w("w0");
   w.factory("PROD::model(Gaussian::xpdf(x[0,-10,10],m_x[0,-1,1],sigma_x[2,0.1,5]), Gaussian::ypdf(y[0,-10,10],m_y[0,-1,1],sigma_y[3,0.1,5]))");
   w.writeToFile("tttxxx.root");

   // We define our work item
   auto workItem = [&](UInt_t workerID) {
      // One generator, file and ntuple per worker
//       TRandom3 workerRndm(workerID); // Change the seed
      auto tt = std::to_string(workerID);
      auto tx = "_"+tt;

      auto wh1d = h1d.Get();
      wh1d->SetBit(TH1::kAutoBinPTwo);
      auto wh1dr = h1dr.Get();

      RooWorkspace w1(("wxx"+tx).c_str());
      w1.import("tttxxx.root:w0:model",RooFit::RenameAllVariables(tt.c_str()),RooFit::RenameAllNodes(tt.c_str()));
//       w1.Print("v");
      auto xvar = w1.var(("x"+tx).c_str());
      auto yvar = w1.var(("y"+tx).c_str());
      auto pdf = w1.pdf(("model"+tx).c_str());
//       xvar->SetName(("x"+tx).c_str());
//       yvar->SetName(("y"+tx).c_str());
//       pdf->SetName(("model"+tx).c_str());
//       xvar->Print("v");
//       yvar->Print("v");
//       pdf->Print("v");

      auto data = pdf->generate(RooArgSet(*xvar,*yvar), nNumbers, RooFit::Name(("data_"+tt).c_str()));
      auto toy_obs = data->get();
      auto toy_obs0 = dynamic_cast<RooRealVar*>((*toy_obs)[0]);
      auto toy_obs1 = dynamic_cast<RooRealVar*>((*toy_obs)[1]);
      for (UInt_t i = 0; i < nNumbers; ++i) {
        data->get(i);
        wh1d->Fill(toy_obs0->getVal(),toy_obs1->getVal());
        wh1dr->Fill(toy_obs0->getVal(),toy_obs1->getVal());
      }

//       auto wh1d = h1d.Get();
//       wh1d->SetBit(TH1::kAutoBinPTwo);
//       auto wh1dr = h1dr.Get();
// 
//       Double_t x;
//       for (UInt_t i = 0; i < nNumbers; ++i) {
//          x = workerRndm.Gaus(3.);
//          wh1d->Fill(x);
//          wh1dr->Fill(x);
//       }
   };

   // Create the collection which will hold the threads, our "pool"
   std::vector<std::thread> workers;

   // Fill the "pool" with workers
   for (auto workerID : ROOT::TSeqI(nWorkers)) {
      workers.emplace_back(workItem, workerID);
   }

   // Now join them
   for (auto &&worker : workers)
      worker.join();

   // Merge
   auto fh1d = h1d.Merge();
   auto fh1dr = h1dr.Merge();

   // Make the canvas
   auto c = new TCanvas("c", "c", 800, 800);
   c->Divide(1, 2);

   gStyle->SetOptStat(111110);
   c->cd(1);
   fh1d->DrawCopy();
   c->cd(2);
   fh1dr->DrawCopy();

   c->Update();

   return 0;
}