#include "TFormula.h"
#include "TThread.h"
#include "TObject.h"
#include "TVirtualStreamerInfo.h"
#include <thread>
#include <memory>
#include <atomic>
#include <cassert>
#include <iostream>

void printHelp(const char* iName, int iDefaultNThreads) {
  std::cout << iName << " [number of threads] \n\n"
            << "If no arguments are given " << iDefaultNThreads << " threads will be used" << std::endl;
}

int parseOptionsForNumberOfThreads(int argc, char** argv) {
  constexpr int kDefaultNThreads = 4;
  int returnValue = kDefaultNThreads;
  if (argc == 2) {
    if (strcmp("-h", argv[1]) == 0) {
      printHelp(argv[0], kDefaultNThreads);
      exit(0);
    }

    returnValue = atoi(argv[1]);
  }

  if (argc > 2) {
    printHelp(argv[0], kDefaultNThreads);
    exit(1);
  }
  return returnValue;
}

int main(int argc, char** argv) {
  const int kNThreads = parseOptionsForNumberOfThreads(argc, argv);

  std::atomic<int> canStart{kNThreads};
  std::vector<std::thread> threads;

  TThread::Initialize();
  //When threading, also have to keep ROOT from logging all TObjects into a list
  TObject::SetObjectStat(false);

  //Have to avoid having Streamers modify themselves after they have been used
  TVirtualStreamerInfo::Optimize(false);

  for (int i = 0; i < kNThreads; ++i) {
    threads.emplace_back([&canStart]() {
      static thread_local TThread guard;
      --canStart;
      while (canStart > 0) {
      }

      TFormula f("testFormula", "1./(1.+(4.61587e+06*(((1./(0.5*TMath::Max(1.e-6,x+1.)))-1.)/1.16042e+07)))");

      for (int i = 0; i < 100; ++i) {
        double x = double(i) / 100.;
        f.Eval(x);
      }
    });
  }
  canStart = true;

  for (auto& thread : threads) {
    thread.join();
  }

  return 0;
}