#ifndef TESTER_H
#define TESTER_H

// Examples:
// tester<std::chrono::nanoseconds>::run_once(std::bind(&class::method, instance_ptr, std::placeholder::_1), 5);
// tester<std::chrono::microseconds>::run_const_iter<10>(func, 6);
// tester<std::chrono::nanoseconds>::run_dyn_iter(1000000, func, 6);


#include <chrono>


template<size_t count>
class run_loop {
public:
	template<typename Callable, typename ...Args>
	static inline void run(Callable&& func, Args&&... args) {
		volatile auto result = std::forward<decltype(func)>(func)(std::forward<Args>(args)...);
		(void)result;
		run_loop<count - 1>::run(func, args...);
	}
};

template<>
class run_loop<1> {
public:
	template<typename Callable, typename ...Args>
	static inline void run(Callable&& func, Args&&... args) {
		volatile auto result = std::forward<decltype(func)>(func)(std::forward<Args>(args)...);
		(void)result;
	}
};


template<typename Time_t = std::chrono::milliseconds, typename Clock_t = std::chrono::high_resolution_clock>
class tester {
public:
	template<typename Callable, typename ...Args>
	static typename Time_t::rep run_once(Callable&& func, Args&&... args) {
		return run_const_iter<1>(func, args...);
	}

	template<typename Callable, typename ...Args>
	static typename Time_t::rep run_dyn_iter(size_t iterations, Callable&& func, Args&&... args) {
		auto start = Clock_t::now();
		for (size_t i = 0; i < iterations; ++i) {
			run_loop<1>::run(func, args...);
		}
		auto duration = std::chrono::duration_cast<Time_t>(Clock_t::now() - start);
		return duration.count();
	}

	template<size_t iters, typename Callable, typename ...Args>
	static typename Time_t::rep run_const_iter(Callable&& func, Args&&... args) {
		auto start = Clock_t::now();
		run_loop<iters>::run(func, args...);
		auto duration = std::chrono::duration_cast<Time_t>(Clock_t::now() - start);
		return duration.count();
	}
};


#endif // TESTER_H