core_future/tjp/core/future/Future.hpp

// License: Modified MIT (NON-AI)
// See the LICENSE file in the root directory for license information.
// Copyright 2026 Timothy Prepscius

#pragma once

#include "Future.h"
#include "./custom/Future.hpp"
#include <tjp/core/algorithm/copy_of.hpp>

namespace tjp {
namespace core {

template<typename R, typename F>
Promise<R> &promise_of(Promise<R> &p, F &&f)
{
	p.consume(f);
	return p;
}

template<typename F>
auto future_of(F &&f)
{
	using R_Ref = decltype(f());
	using R = std::remove_reference_t<R_Ref>;

	Promise<R> promise;
	promise.consume(f);
	return promise.get_future();
}

template<typename F, typename ... Args>
auto future_of(F &&f, Args && ... args)
{
	using R_Ref = decltype(f(std::forward<Args>(args)...));
	using R = std::remove_reference_t<R_Ref>;

	Promise<R> promise;
	promise.consume(f, std::forward<Args>(args)...);
	return promise.get_future();
}

template<typename T>
auto future_of_value(T &&t)
{
	using T_ = std::remove_reference_t<T>;
	Promise<T_> promise;
	
	promise.set_value(std::forward<T>(t));
	return promise.get_future();
}

template<typename T>
Future<T> future_of_value(const T &t)
{
	Promise<T> promise;
	promise.set_value(t);
	return promise.get_future();
}

inline
Future<void> future_of_value()
{
	Promise<void> promise;
	promise.set_value();
	return promise.get_future();
}

template<typename T, typename E>
Future<T> future_of_exception(E &&e)
{
	Promise<T> promise;
	promise.set_exception(std::forward<E>(e));
	return promise.get_future();
}

template<typename T, typename E>
Future<T> future_of_exception(const E &e)
{
	return future_of_exception<T, E>(E(e));
}

template<typename F>
auto future_with(F &&f)
{
	using R_Ref = decltype(f());
	using R = std::remove_reference_t<R_Ref>;
	
	if constexpr (is_future<R>::value)
	{
		using RV = typename R::value_type;
		
		try
		{
			return f();
		}
		CORE_FUTURE_CATCH_BEGIN(e)
		{
			return future_of_exception<RV>(e);
		}
		CORE_FUTURE_CATCH_END
	}
	else
	{
		return future_of(f);
	}
}

template<typename F, typename ... Args>
auto future_with(F &&f, Args && ...args)
{
	using R_Ref = decltype(f(std::forward<Args>(args)...));
	using R = std::remove_reference_t<R_Ref>;
	
	if constexpr (is_future<R>::value)
	{
		using RV = typename R::value_type;
		
		try
		{
			return f(std::forward<Args>(args)...);
		}
		CORE_FUTURE_CATCH_BEGIN(e)
		{
			return future_of_exception<RV>(e);
		}
		CORE_FUTURE_CATCH_END
	}
	else
	{
		return future_of(f, std::forward<Args>(args)...);
	}
}

template<typename T>
struct AsFuture_
{
	T v;
	
	template<typename U>
	operator Future<U>()
	{
		return future_of_value<U>(std::move(v));
	}
};

template<>
struct AsFuture_<void>
{
	template<typename U>
	operator Future<U>()
	{
		return future_of_value();
	}
} ;

template<typename T>
AsFuture_<T> as_future(T &&t)
{
	return AsFuture_<std::remove_reference_t<T>> { std::forward<T>(t) };
}

inline
AsFuture_<void> as_future()
{
	return AsFuture_<void> { };
}

template<typename T>
struct AsFutureException_
{
	T v;
	
	template<typename U>
	operator Future<U>()
	{
		return future_of_exception<U>(std::move(v));
	}
};

template<typename T>
AsFutureException_<T> as_future_exception(T &&t)
{
	return AsFutureException_<std::remove_reference_t<T>> { std::forward<T>(t) };
}


//template<typename F>
//auto future_with(F f) -> decltype(f()) {
//	using R = typename decltype(f())::value_type;
//	try {
//		return f();
//	}
//	catch (Exception &e) {
//		return future_of_exception<R>(copy_of(e));
//	}
//}


//template<typename R, typename ...T, typename std::enable_if<!is_future<R>::value, R>::type*>
//auto with(std::function<R(T&&...)> &&f) {
//	return f;
//}
//

} // namespace
} // namespace