// License: Modified MIT (NON-AI)
// See the LICENSE file in the root directory for license information.
// Copyright 2025 Timothy Prepscius

#pragma once

#include "Timer.h"
#include <chrono>
#include <thread>

#include "../containers/Optional.hpp"
#include "../assert/debug_assert.h"

namespace tjp::core {

class Timer
{
  public:
	typedef double Time;
	typedef double Duration;
	
	Duration accumulator = 0;
	Optional<std::chrono::time_point<std::chrono::high_resolution_clock>> then;

	Timer()
	{
		start();
	}

	Timer(bool start_)
	{
		if (start_)
			start();
	}

	auto now() const
	{
		return std::chrono::high_resolution_clock::now();
	}

	void start()
	{
		debug_assert(!then);
		
		accumulator = 0;
		then = now();
	}
	
	void restart()
	{
		then.reset();
		start();
	}

	bool running ()
	{
		return then.has_value();
	}

	Duration elapsed() const
	{
		if (!then)
			return accumulator;
			
		auto now_ = now();
		auto duration = std::chrono::duration<double>(now_ - *then).count();

		return duration + accumulator;
	}
	
	void pause()
	{
		if (!then)
			return ;
			
		auto now_ = now();
		auto partial = std::chrono::duration<double>(now_ - *then).count();
		then.reset();
		accumulator += partial;
	}
	
	Duration stop()
	{
		pause();
		return accumulator;
	}

	void resume()
	{
		debug_assert(!then);
		
		then = now();
	}
};

} // namespace