#ifndef _THREADPOOL_H_
#define _THREADPOOL_H_

#include <thread>
#include <mutex>
#include <condition_variable>
#include <functional>
#include <queue>
#include <vector>
#include <future>

class threadpool
{
private:
	std::size_t _concurrency;
	std::queue<std::function<void()>> _queue;
	std::mutex _mutex;
	std::condition_variable _cv;
	std::vector<std::thread> _workers;
	bool _enabled;

public:
	threadpool();
	threadpool(std::size_t concurrency);
	~threadpool();

	template <typename R> std::future<R> add_task(std::function<R()> func)
	{
		std::lock_guard<std::mutex> lock(_mutex);
		std::shared_ptr<std::packaged_task<R()>> pt_ptr = std::make_shared<std::packaged_task<R()>>(func);
		std::future<R> fut = pt_ptr->get_future();

		std::function<void()> tf = [pt_ptr] { (*pt_ptr)(); };
		_queue.push(tf);
		_cv.notify_one();
		return fut;
	}

private:
	void worker_func();
};

#endif // _THREADPOOL_H_