// The MIT License (MIT) 

// Copyright (c) 2013-2016 Rapptz, 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_RESOLVE_HPP
#define SOL_RESOLVE_HPP

#include "traits.hpp"
#include "tuple.hpp"

namespace sol {
	
#ifndef __clang__
	// constexpr is fine for not-clang

	namespace detail {
		template<typename R, typename... Args, typename F, typename = std::result_of_t<meta::unqualified_t<F>(Args...)>>
		inline constexpr auto resolve_i(types<R(Args...)>, F&&)->R(meta::unqualified_t<F>::*)(Args...) {
			using Sig = R(Args...);
			typedef meta::unqualified_t<F> Fu;
			return static_cast<Sig Fu::*>(&Fu::operator());
		}

		template<typename F, typename U = meta::unqualified_t<F>>
		inline constexpr auto resolve_f(std::true_type, F&& f)
			-> decltype(resolve_i(types<meta::function_signature_t<decltype(&U::operator())>>(), std::forward<F>(f))) {
			return resolve_i(types<meta::function_signature_t<decltype(&U::operator())>>(), std::forward<F>(f));
		}

		template<typename F>
		inline constexpr void resolve_f(std::false_type, F&&) {
			static_assert(meta::has_deducible_signature<F>::value,
				"Cannot use no-template-parameter call with an overloaded functor: specify the signature");
		}

		template<typename F, typename U = meta::unqualified_t<F>>
		inline constexpr auto resolve_i(types<>, F&& f) -> decltype(resolve_f(meta::has_deducible_signature<U>(), std::forward<F>(f))) {
			return resolve_f(meta::has_deducible_signature<U> {}, std::forward<F>(f));
		}

		template<typename... Args, typename F, typename R = std::result_of_t<F&(Args...)>>
		inline constexpr auto resolve_i(types<Args...>, F&& f) -> decltype(resolve_i(types<R(Args...)>(), std::forward<F>(f))) {
			return resolve_i(types<R(Args...)>(), std::forward<F>(f));
		}

		template<typename Sig, typename C>
		inline constexpr Sig C::* resolve_v(std::false_type, Sig C::* mem_func_ptr) {
			return mem_func_ptr;
		}

		template<typename Sig, typename C>
		inline constexpr Sig C::* resolve_v(std::true_type, Sig C::* mem_variable_ptr) {
			return mem_variable_ptr;
		}
	} // detail

	template<typename... Args, typename R>
	inline constexpr auto resolve(R fun_ptr(Args...))->R(*)(Args...) {
		return fun_ptr;
	}

	template<typename Sig>
	inline constexpr Sig* resolve(Sig* fun_ptr) {
		return fun_ptr;
	}

	template<typename... Args, typename R, typename C>
	inline constexpr auto resolve(R(C::*mem_ptr)(Args...))->R(C::*)(Args...) {
		return mem_ptr;
	}

	template<typename Sig, typename C>
	inline constexpr Sig C::* resolve(Sig C::* mem_ptr) {
		return detail::resolve_v(std::is_member_object_pointer<Sig C::*>(), mem_ptr);
	}

	template<typename... Sig, typename F, meta::disable<std::is_function<meta::unqualified_t<F>>> = meta::enabler>
	inline constexpr auto resolve(F&& f) -> decltype(detail::resolve_i(types<Sig...>(), std::forward<F>(f))) {
		return detail::resolve_i(types<Sig...>(), std::forward<F>(f));
	}
#else

	// Clang has distinct problems with constexpr arguments,
	// so don't use the constexpr versions inside of clang.

	namespace detail {
		template<typename R, typename... Args, typename F, typename = std::result_of_t<meta::unqualified_t<F>(Args...)>>
		inline auto resolve_i(types<R(Args...)>, F&&)->R(meta::unqualified_t<F>::*)(Args...) {
			using Sig = R(Args...);
			typedef meta::unqualified_t<F> Fu;
			return static_cast<Sig Fu::*>(&Fu::operator());
		}

		template<typename F, typename U = meta::unqualified_t<F>>
		inline auto resolve_f(std::true_type, F&& f)
			-> decltype(resolve_i(types<meta::function_signature_t<decltype(&U::operator())>>(), std::forward<F>(f))) {
			return resolve_i(types<meta::function_signature_t<decltype(&U::operator())>>(), std::forward<F>(f));
		}

		template<typename F>
		inline void resolve_f(std::false_type, F&&) {
			static_assert(meta::has_deducible_signature<F>::value,
				"Cannot use no-template-parameter call with an overloaded functor: specify the signature");
		}

		template<typename F, typename U = meta::unqualified_t<F>>
		inline auto resolve_i(types<>, F&& f) -> decltype(resolve_f(meta::has_deducible_signature<U>(), std::forward<F>(f))) {
			return resolve_f(meta::has_deducible_signature<U> {}, std::forward<F>(f));
		}

		template<typename... Args, typename F, typename R = std::result_of_t<F&(Args...)>>
		inline auto resolve_i(types<Args...>, F&& f) -> decltype(resolve_i(types<R(Args...)>(), std::forward<F>(f))) {
			return resolve_i(types<R(Args...)>(), std::forward<F>(f));
		}

		template<typename Sig, typename C>
		inline Sig C::* resolve_v(std::false_type, Sig C::* mem_func_ptr) {
			return mem_func_ptr;
		}

		template<typename Sig, typename C>
		inline Sig C::* resolve_v(std::true_type, Sig C::* mem_variable_ptr) {
			return mem_variable_ptr;
		}
	} // detail

	template<typename... Args, typename R>
	inline auto resolve(R fun_ptr(Args...))->R(*)(Args...) {
		return fun_ptr;
	}

	template<typename Sig>
	inline Sig* resolve(Sig* fun_ptr) {
		return fun_ptr;
	}

	template<typename... Args, typename R, typename C>
	inline auto resolve(R(C::*mem_ptr)(Args...))->R(C::*)(Args...) {
		return mem_ptr;
	}

	template<typename Sig, typename C>
	inline Sig C::* resolve(Sig C::* mem_ptr) {
		return detail::resolve_v(std::is_member_object_pointer<Sig C::*>(), mem_ptr);
	}

	template<typename... Sig, typename F>
	inline auto resolve(F&& f) -> decltype(detail::resolve_i(types<Sig...>(), std::forward<F>(f))) {
		return detail::resolve_i(types<Sig...>(), std::forward<F>(f));
	}

#endif

} // sol

#endif // SOL_RESOLVE_HPP
