// The MIT License (MIT) 

// Copyright (c) 2013-2017 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_STACK_CHECK_GET_HPP
#define SOL_STACK_CHECK_GET_HPP

#include "stack_core.hpp"
#include "stack_get.hpp"
#include "stack_check.hpp"
#include "optional.hpp"
#include <cstdlib>
#include <cmath>

namespace sol {
	namespace stack {
		template <typename T, typename>
		struct check_getter {
			typedef decltype(stack_detail::unchecked_get<T>(nullptr, 0, std::declval<record&>())) R;

			template <typename Handler>
			static optional<R> get(lua_State* L, int index, Handler&& handler, record& tracking) {
				if (!check<T>(L, index, std::forward<Handler>(handler))) {
					tracking.use(static_cast<int>(!lua_isnone(L, index)));
					return nullopt;
				}
				return stack_detail::unchecked_get<T>(L, index, tracking);
			}
		};

		template <typename T>
		struct check_getter<optional<T>> {
			template <typename Handler>
			static decltype(auto) get(lua_State* L, int index, Handler&&, record& tracking) {
				return check_get<T>(L, index, no_panic, tracking);
			}
		};

		template <typename T>
		struct check_getter<T, std::enable_if_t<std::is_integral<T>::value && lua_type_of<T>::value == type::number>> {
			template <typename Handler>
			static optional<T> get(lua_State* L, int index, Handler&& handler, record& tracking) {
#if SOL_LUA_VERSION >= 503
				if (lua_isinteger(L, index) != 0) {
					tracking.use(1);
					return static_cast<T>(lua_tointeger(L, index));
				}
#endif
				int isnum = 0;
				const lua_Number value = lua_tonumberx(L, index, &isnum);
				if (isnum != 0) {
#if 1 // defined(SOL_CHECK_ARGUMENTS) && !defined(SOL_NO_CHECK_NUMBER_PRECISION)
					const auto integer_value = llround(value);
					if (static_cast<lua_Number>(integer_value) == value) {
						tracking.use(1);
						return static_cast<T>(integer_value);
					}
#else
					tracking.use(1);
					return static_cast<T>(value);
#endif
				}
				const type t = type_of(L, index);
				tracking.use(static_cast<int>(t != type::none));
				handler(L, index, type::number, t);
				return nullopt;
			}
		};

		template <typename T>
		struct check_getter<T, std::enable_if_t<std::is_enum<T>::value && !meta::any_same<T, meta_function, type>::value>> {
			template <typename Handler>
			static optional<T> get(lua_State* L, int index, Handler&& handler, record& tracking) {
				int isnum = 0;
				lua_Integer value = lua_tointegerx(L, index, &isnum);
				if (isnum == 0) {
					type t = type_of(L, index);
					tracking.use(static_cast<int>(t != type::none));
					handler(L, index, type::number, t);
					return nullopt;
				}
				tracking.use(1);
				return static_cast<T>(value);
			}
		};

		template <typename T>
		struct check_getter<T, std::enable_if_t<std::is_floating_point<T>::value>> {
			template <typename Handler>
			static optional<T> get(lua_State* L, int index, Handler&& handler, record& tracking) {
				int isnum = 0;
				lua_Number value = lua_tonumberx(L, index, &isnum);
				if (isnum == 0) {
					type t = type_of(L, index);
					tracking.use(static_cast<int>(t != type::none));
					handler(L, index, type::number, t);
					return nullopt;
				}
				tracking.use(1);
				return static_cast<T>(value);
			}
		};

		template <typename T>
		struct getter<optional<T>> {
			static decltype(auto) get(lua_State* L, int index, record& tracking) {
				return check_get<T>(L, index, no_panic, tracking);
			}
		};

#ifdef SOL_CXX17_FEATURES
		template <typename... Tn>
		struct check_getter<std::variant<Tn...>> {
			typedef std::variant<Tn...> V;
			typedef std::variant_size<V> V_size;
			typedef std::integral_constant<bool, V_size::value == 0> V_is_empty;

			template <typename Handler>
			static optional<V> get_empty(std::true_type, lua_State* L, int index, Handler&& handler, record& tracking) {
				return nullopt;
			}

			template <typename Handler>
			static optional<V> get_empty(std::false_type, lua_State* L, int index, Handler&& handler, record& tracking) {
				typedef std::variant_alternative_t<0, V> T;
				// This should never be reached...
				// please check your code and understand what you did to bring yourself here
				handler(L, index, type::poly, type_of(L, index));
				return nullopt;
			}

			template <typename Handler>
			static optional<V> get_one(std::integral_constant<std::size_t, 0>, lua_State* L, int index, Handler&& handler, record& tracking) {
				return get_empty(V_is_empty(), L, index, std::forward<Handler>(handler), tracking);
			}

			template <std::size_t I, typename Handler>
			static optional<V> get_one(std::integral_constant<std::size_t, I>, lua_State* L, int index, Handler&& handler, record& tracking) {
				typedef std::variant_alternative_t<I - 1, V> T;
				if (stack::check<T>(L, index, no_panic, tracking)) {
					return V(std::in_place_index<I - 1>, stack::get<T>(L, index));
				}
				return get_one(std::integral_constant<std::size_t, I - 1>(), L, index, std::forward<Handler>(handler), tracking);
			}

			template <typename Handler>
			static optional<V> get(lua_State* L, int index, Handler&& handler, record& tracking) {
				return get_one(std::integral_constant<std::size_t, V_size::value>(), L, index, std::forward<Handler>(handler), tracking);
			}
		};
#endif // C++17
	} // stack
} // sol

#endif // SOL_STACK_CHECK_GET_HPP