#pragma once

#include <tuple>
#include <type_traits>

namespace sqlite
{
namespace utility
{

template <typename> struct function_traits;

template <typename Function>
struct function_traits : public function_traits<decltype(&std::remove_reference<Function>::type::operator())>
{
};

template <typename ClassType, typename ReturnType, typename... Arguments>
struct function_traits<ReturnType (ClassType::*)(Arguments...) const> : function_traits<ReturnType (*)(Arguments...)>
{
};

/* support the non-const operator ()
 * this will work with user defined functors */
template <typename ClassType, typename ReturnType, typename... Arguments>
struct function_traits<ReturnType (ClassType::*)(Arguments...)> : function_traits<ReturnType (*)(Arguments...)>
{
};

template <typename ReturnType, typename... Arguments> struct function_traits<ReturnType (*)(Arguments...)>
{
	typedef ReturnType result_type;

	template <std::size_t Index> using argument = typename std::tuple_element<Index, std::tuple<Arguments...>>::type;

	static const std::size_t arity = sizeof...(Arguments);
};

} // namespace utility
} // namespace sqlite