/* #define DEBUGTRACE_ENABLED */
#include "lasp_thread.h"
#include "BS_thread_pool.hpp"
#include "debugtrace.hpp"
#include <memory>

/**
 * @brief Store a global weak_ptr, that is used to create new shared pointers
 * if any other shared pointers are still alive. If not, we create a new
 * instance.
 */
std::weak_ptr<BS::thread_pool> _global_weak_pool;

/**
 * @brief Global mutex, used to restrict the pool creation to a single thread
 * at once.
 */
std::mutex _mtx;

using Lck = std::scoped_lock<std::mutex>;
using rte = std::runtime_error;

GlobalThreadPool::GlobalThreadPool() {
  DEBUGTRACE_ENTER;
  Lck lck(_mtx);
  /// See if we can get it from the global ptr. If not, time to allocate it.
  _pool = _global_weak_pool.lock();
  if (!_pool) {
    _pool = std::make_shared<BS::thread_pool>();
    if (!_pool) {
      throw rte("Fatal: could not allocate thread pool!");
    }
    // Update global weak pointer
    _global_weak_pool = _pool;
  }
}