// Some of the ROOT stuff we will need...
#include <TFile.h>
#include <TTree.h>
#include <TGraph.h>
#include <TH1F.h>
#include <TCanvas.h>
// Stuff for RooFit.
#include <RooRealVar.h>
#include <RooDataSet.h>
#include <RooPlot.h>
#include <RooArgSet.h>
#include <RooCategory.h>
#include <RooAbsReal.h>
#include <RooPoisson.h>
#include <RooMinuit.h>
#include <RooNLLVar.h>
#include <RooFormulaVar.h>
#include <iostream>

using namespace RooFit;

int main(int argc, char* argv[]){


  // This is our observable.
  RooRealVar t0("t0", "t0", -1e3, 1e3);
  
  // Let the first input be the name of the ROOT file.
  std::cout << "Opening the TFiles!" << std::endl;
  std::string ROOTFilename = argv[1];
  std::string ROOTTTree = argv[2];
  std::cout << ROOTTTree << std::endl;
  // Open said ROOT file and get the TTree (second argument).
  TFile* f = new TFile(ROOTFilename.c_str(), "OPEN");
  TTree* t = (TTree*)f->Get(ROOTTTree.c_str());

  std::cout << "Creating the observed dataset!" << std::endl;
  // Store the dataset into a RooDataSet with RooRealVar.
  // vFlag is for the cuts (i.e. Did it stop in lead?)
  RooRealVar tim("time", "time", -1e9, 10e9);
  RooRealVar cts("counts", "counts", 0, 100);
    
  RooDataSet data("data", "data", RooArgSet(tim,cts), Import(*t));
  
  // Open the second file and get the mean as a function of time.
  TFile* f2 = new TFile("t0-analyzed.root", "OPEN");
  TTree* t2 = (TTree*)f2->Get("mean");
  
  // Store these in a RooRealVar.
  RooRealVar meanTime("meanTime", "meanTime", -1e9, 10e9);
  RooRealVar meanCounts("meanCounts", "meanCounts", 0, 30);

  std::cout << "Creating the mean dataset!" << std::endl;
  // Form the dataset for the mean.
  RooDataSet mean("mean", "mean", RooArgSet(meanTime, meanCounts), Import(*t2));
  // We subtract out t0 to the time.
  RooFormulaVar tPrime("tPrime", "meanTime-t0", RooArgList(t0,meanTime));
  RooPoisson poisson("poisson", "poisson", tPrime, meanCounts, kFALSE);
  
  RooAbsReal* nll = poisson.createNLL(data, NumCPU(2));
  RooMinuit(*nll).migrad();

  TCanvas* c = new TCanvas("c", "c", 400, 400);
  
  RooPlot* frame1 = t0.frame(Range(-1e3,1e3), Title("Test Likelihood"));
  nll->plotOn(frame1);
  frame1->Draw();
  
  f->Close();
  f2->Close();

  c->Print("test.png");

  return 0;
  
}