// The MIT License (MIT)

// Copyright (c) 2013-2016 Rappt1101010z, ThePhD and contributors

// Permission is hereby granted, free of charge, to any person obtaining a copy of
// this software and associated documentation files (the "Software"), to deal in
// the Software without restriction, including without limitation the rights to
// use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
// the Software, and to permit persons to whom the Software is furnished to do so,
// subject to the following conditions:

// The above copyright notice and this permission notice shall be included in all
// copies or substantial portions of the Software.

// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
// FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
// COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
// IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
// CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

#ifndef SOL_BIND_TRAITS_HPP
#define SOL_BIND_TRAITS_HPP

#include "tuple.hpp"

namespace sol {
	namespace meta {
		namespace meta_detail {

			template<class F>
			struct check_deducible_signature {
				struct nat {};
				template<class G>
				static auto test(int) -> decltype(&G::operator(), void());
				template<class>
				static auto test(...)->nat;

				using type = std::is_void<decltype(test<F>(0))>;
			};
		} // meta_detail

		template<class F>
		struct has_deducible_signature : meta_detail::check_deducible_signature<F>::type { };

		namespace meta_detail {

			template <std::size_t I, typename T>
			struct void_tuple_element : meta::tuple_element<I, T> {};

			template <std::size_t I>
			struct void_tuple_element<I, std::tuple<>> { typedef void type; };

			template <std::size_t I, typename T>
			using void_tuple_element_t = typename void_tuple_element<I, T>::type;

			template <bool has_c_variadic, typename T, typename R, typename... Args>
			struct basic_traits {
			private:
				typedef std::conditional_t<std::is_void<T>::value, int, T>& first_type;

			public:
				static const bool is_member_function = std::is_void<T>::value;
				static const bool has_c_var_arg = has_c_variadic;
				static const std::size_t arity = sizeof...(Args);
				static const std::size_t free_arity = sizeof...(Args)+static_cast<std::size_t>(!std::is_void<T>::value);
				typedef types<Args...> args_list;
				typedef std::tuple<Args...> args_tuple;
				typedef T object_type;
				typedef R return_type;
				typedef tuple_types<R> returns_list;
				typedef R(function_type)(Args...);
				typedef std::conditional_t<std::is_void<T>::value, args_list, types<first_type, Args...>> free_args_list;
				typedef std::conditional_t<std::is_void<T>::value, R(Args...), R(first_type, Args...)> free_function_type;
				typedef std::conditional_t<std::is_void<T>::value, R(*)(Args...), R(*)(first_type, Args...)> free_function_pointer_type;
				typedef std::remove_pointer_t<free_function_pointer_type> signature_type;
				template<std::size_t i>
				using arg_at = void_tuple_element_t<i, args_tuple>;
			};

			template<typename Signature, bool b = has_deducible_signature<Signature>::value>
			struct fx_traits : basic_traits<false, void, void> {};

			// Free Functions
			template<typename R, typename... Args>
			struct fx_traits<R(Args...), false> : basic_traits<false, void, R, Args...> {
				typedef R(*function_pointer_type)(Args...);
			};

			template<typename R, typename... Args>
			struct fx_traits<R(*)(Args...), false> : basic_traits<false, void, R, Args...> {
				typedef R(*function_pointer_type)(Args...);
			};

			template<typename R, typename... Args>
			struct fx_traits<R(Args..., ...), false> : basic_traits<true, void, R, Args...> {
				typedef R(*function_pointer_type)(Args..., ...);
			};

			template<typename R, typename... Args>
			struct fx_traits<R(*)(Args..., ...), false> : basic_traits<true, void, R, Args...> {
				typedef R(*function_pointer_type)(Args..., ...);
			};

			// Member Functions
			/* C-Style Variadics */
			template<typename T, typename R, typename... Args>
			struct fx_traits<R(T::*)(Args...), false> : basic_traits<false, T, R, Args...> {
				typedef R(T::* function_pointer_type)(Args...);
			};

			template<typename T, typename R, typename... Args>
			struct fx_traits<R(T::*)(Args..., ...), false> : basic_traits<true, T, R, Args...> {
				typedef R(T::* function_pointer_type)(Args..., ...);
			};

			/* Const Volatile */
			template<typename T, typename R, typename... Args>
			struct fx_traits<R(T::*)(Args...) const, false> : basic_traits<false, T, R, Args...> {
				typedef R(T::* function_pointer_type)(Args...) const;
			};

			template<typename T, typename R, typename... Args>
			struct fx_traits<R(T::*)(Args..., ...) const, false> : basic_traits<true, T, R, Args...> {
				typedef R(T::* function_pointer_type)(Args..., ...) const;
			};

			template<typename T, typename R, typename... Args>
			struct fx_traits<R(T::*)(Args...) const volatile, false> : basic_traits<false, T, R, Args...> {
				typedef R(T::* function_pointer_type)(Args...) const volatile;
			};

			template<typename T, typename R, typename... Args>
			struct fx_traits<R(T::*)(Args..., ...) const volatile, false> : basic_traits<true, T, R, Args...> {
				typedef R(T::* function_pointer_type)(Args..., ...) const volatile;
			};

			/* Member Function Qualifiers */
			template<typename T, typename R, typename... Args>
			struct fx_traits<R(T::*)(Args...) &, false> : basic_traits<false, T, R, Args...> {
				typedef R(T::* function_pointer_type)(Args...) &;
			};

			template<typename T, typename R, typename... Args>
			struct fx_traits<R(T::*)(Args..., ...) &, false> : basic_traits<true, T, R, Args...> {
				typedef R(T::* function_pointer_type)(Args..., ...) &;
			};

			template<typename T, typename R, typename... Args>
			struct fx_traits<R(T::*)(Args...) const &, false> : basic_traits<false, T, R, Args...> {
				typedef R(T::* function_pointer_type)(Args...) const &;
			};

			template<typename T, typename R, typename... Args>
			struct fx_traits<R(T::*)(Args..., ...) const &, false> : basic_traits<true, T, R, Args...> {
				typedef R(T::* function_pointer_type)(Args..., ...) const &;
			};

			template<typename T, typename R, typename... Args>
			struct fx_traits<R(T::*)(Args...) const volatile &, false> : basic_traits<false, T, R, Args...> {
				typedef R(T::* function_pointer_type)(Args...) const volatile &;
			};

			template<typename T, typename R, typename... Args>
			struct fx_traits<R(T::*)(Args..., ...) const volatile &, false> : basic_traits<true, T, R, Args...> {
				typedef R(T::* function_pointer_type)(Args..., ...) const volatile &;
			};

			template<typename T, typename R, typename... Args>
			struct fx_traits<R(T::*)(Args...) && , false> : basic_traits<false, T, R, Args...> {
				typedef R(T::* function_pointer_type)(Args...) && ;
			};

			template<typename T, typename R, typename... Args>
			struct fx_traits<R(T::*)(Args..., ...) && , false> : basic_traits<true, T, R, Args...> {
				typedef R(T::* function_pointer_type)(Args..., ...) && ;
			};

			template<typename T, typename R, typename... Args>
			struct fx_traits<R(T::*)(Args...) const &&, false> : basic_traits<false, T, R, Args...> {
				typedef R(T::* function_pointer_type)(Args...) const &&;
			};

			template<typename T, typename R, typename... Args>
			struct fx_traits<R(T::*)(Args..., ...) const &&, false> : basic_traits<true, T, R, Args...> {
				typedef R(T::* function_pointer_type)(Args..., ...) const &&;
			};

			template<typename T, typename R, typename... Args>
			struct fx_traits<R(T::*)(Args...) const volatile &&, false> : basic_traits<false, T, R, Args...> {
				typedef R(T::* function_pointer_type)(Args...) const volatile &&;
			};

			template<typename T, typename R, typename... Args>
			struct fx_traits<R(T::*)(Args..., ...) const volatile &&, false> : basic_traits<true, T, R, Args...> {
				typedef R(T::* function_pointer_type)(Args..., ...) const volatile &&;
			};

			template<typename Signature>
			struct fx_traits<Signature, true> : fx_traits<typename fx_traits<decltype(&Signature::operator())>::function_type, false> {};

			template<typename Signature, bool b = std::is_member_object_pointer<Signature>::value>
			struct callable_traits : fx_traits<std::decay_t<Signature>> {

			};

			template<typename R, typename T>
			struct callable_traits<R(T::*), true> {
				typedef R Arg;
				typedef T object_type;
				using signature_type = R(T::*);
				static const bool is_member_function = false;
				static const std::size_t arity = 1;
				static const std::size_t free_arity = 2;
				typedef std::tuple<Arg> args_tuple;
				typedef R return_type;
				typedef types<Arg> args_list;
				typedef types<T, Arg> free_args_list;
				typedef meta::tuple_types<R> returns_list;
				typedef R(function_type)(T&, R);
				typedef R(*function_pointer_type)(T&, R);
				typedef R(*free_function_pointer_type)(T&, R);
				template<std::size_t i>
				using arg_at = void_tuple_element_t<i, args_tuple>;
			};
		} // meta_detail

		template<typename Signature>
		struct bind_traits : meta_detail::callable_traits<Signature> {};

		template<typename Signature>
		using function_args_t = typename bind_traits<Signature>::args_list;

		template<typename Signature>
		using function_signature_t = typename bind_traits<Signature>::signature_type;

		template<typename Signature>
		using function_return_t = typename bind_traits<Signature>::return_type;

	} // meta
} // sol

#endif // SOL_BIND_TRAITS_HPP