#pragma once

#include "value_functor.hpp"

// NOLINTNEXTLINE(cppcoreguidelines-macro-usage)
#define VALUE_FUNCTOR_TEMPLATE template <class Return, class... Args>

// NOLINTNEXTLINE(cppcoreguidelines-macro-usage)
#define VALUE_FUNCTOR ValueFunctor<Return(Args...)>

VALUE_FUNCTOR_TEMPLATE
VALUE_FUNCTOR::ValueFunctor() noexcept : _functor(nullptr) {}

VALUE_FUNCTOR_TEMPLATE
template <class Function, class Allocator>
VALUE_FUNCTOR::ValueFunctor(Function &&function, const Allocator &allocator)
	: _functor(nullptr)
{
	using AllocTraits = std::allocator_traits<Allocator>;

	using Functor = CopyableFunctor<Function, Allocator, Return(Args...)>;

	using FunctorAlloc = typename RebindAllocHelper<AllocTraits, Functor>::type;

	if (not_null(function))
	{
		auto functor_alloc = FunctorAlloc(allocator);

		if (sizeof(Functor) <= sizeof(_buf) &&
			std::is_nothrow_copy_constructible<Function>::value &&
			std::is_nothrow_copy_constructible<FunctorAlloc>::value)
		{
			// NOLINTNEXTLINE(cppcoreguidelines-owning-memory)
			_functor = ::new (static_cast<void *>(&_buf))
				Functor(std::forward<Function>(function), Allocator(functor_alloc));
		}
		else
		{
			using Destructor = AllocDestructor<FunctorAlloc>;

			auto hold = std::unique_ptr<TargetFunctor, Destructor>(
				functor_alloc.allocate(1),
				Destructor(functor_alloc, 1)
			);

			::new (static_cast<void *>(hold.get()))
				Functor(std::forward<Function>(function), Allocator(allocator));

			_functor = hold.release();
		}
	}
}

VALUE_FUNCTOR_TEMPLATE
VALUE_FUNCTOR::ValueFunctor(const ValueFunctor &val_functor)
{
	if (val_functor._functor == nullptr)
	{
		_functor = nullptr;
	}
	else if (static_cast<void *>(val_functor._functor) == &val_functor._buf)
	{
		_functor = _as_copyable_functor(&_buf);
		val_functor._functor->clone(_functor);
	}
	else
	{
		_functor = val_functor._functor->clone();
	}
}

VALUE_FUNCTOR_TEMPLATE
VALUE_FUNCTOR::ValueFunctor(ValueFunctor &&val_functor) noexcept
{
	if (val_functor._functor == nullptr)
	{
		_functor = nullptr;
	}
	else if (static_cast<void *>(val_functor._functor) == &val_functor._buf)
	{
		_functor = _as_copyable_functor(&_buf);
		val_functor._functor->clone(_functor);
	}
	else
	{
		_functor = val_functor._functor;
		val_functor._functor = nullptr;
	}
}

VALUE_FUNCTOR_TEMPLATE
VALUE_FUNCTOR::~ValueFunctor()
{
	if (static_cast<void *>(_functor) == &_buf)
	{
		_functor->destroy();
	}
	else if (_functor)
	{
		_functor->destroy_deallocate();
	}
}

VALUE_FUNCTOR_TEMPLATE
auto VALUE_FUNCTOR::operator=(ValueFunctor &&val_functor) noexcept -> ValueFunctor &
{
	*this = nullptr;

	if (val_functor._functor == nullptr)
	{
		_functor = nullptr;
	}
	else if (static_cast<void *>(val_functor._functor) == &val_functor._buf)
	{
		_functor = _as_copyable_functor(&_buf);
		val_functor._functor->clone(_functor);
	}
	else
	{
		_functor = val_functor._functor;
		val_functor._functor = nullptr;
	}

	return *this;
}

VALUE_FUNCTOR_TEMPLATE
auto VALUE_FUNCTOR::operator=(std::nullptr_t) -> ValueFunctor &
{
	TargetFunctor *old_functor = _functor;

	_functor = nullptr;

	if (static_cast<void *>(old_functor) == &_buf)
	{
		old_functor->destroy();
	}
	else if (old_functor)
	{
		old_functor->destroy_deallocate();
	}

	return *this;
}

VALUE_FUNCTOR_TEMPLATE
auto VALUE_FUNCTOR::operator()(Args &&...args) const -> Return
{
	if (_functor == nullptr)
	{
		std::abort();
	}

	return (*_functor)(std::forward<Args>(args)...);
}

VALUE_FUNCTOR_TEMPLATE
VALUE_FUNCTOR::operator bool() const noexcept
{
	return _functor != nullptr;
}

VALUE_FUNCTOR_TEMPLATE
auto VALUE_FUNCTOR::target_type() const noexcept -> const std::type_info &
{
	if (_functor == nullptr)
	{
		return typeid(void);
	}

	return _functor->target_type();
}

VALUE_FUNCTOR_TEMPLATE
template <typename Target>
auto VALUE_FUNCTOR::target() const noexcept -> const Target *
{
	if (_functor == nullptr)
	{
		return nullptr;
	}

	return static_cast<const Target *>(_functor->target(typeid(Target)));
}

VALUE_FUNCTOR_TEMPLATE
auto VALUE_FUNCTOR::_as_copyable_functor(void *function_ptr) -> TargetFunctor *
{
	// NOLINTNEXTLINE(cppcoreguidelines-pro-type-reinterpret-cast)
	return reinterpret_cast<TargetFunctor *>(function_ptr);
}