#ifndef stack_h
#define stack_h 1

#include <chrono>
#include <condition_variable>
#include <mutex>
#include <optional>
#include <stack>
#include <thread>

using namespace std::chrono_literals;

template <class T> class stack {
public:
    void push(T t)
    {
        std::unique_lock lock(mutex);
        cv.wait(lock, [&] { return lock.owns_lock(); });
        container.push(std::move(t));
        lock.unlock();
        cv.notify_all();
    }

    std::optional<T> pop()
    {
        std::optional<T> optional;
        std::unique_lock lock(mutex);
        cv.wait(lock, [&] { return lock.owns_lock(); });
        if (!container.empty())
        {
            optional = container.top();
            container.pop();
        }
        lock.unlock();
        cv.notify_all();
        return optional;
    }

private:
    std::mutex mutex;
    std::condition_variable cv;
    std::stack<T> container;
};

#endif // stack_h