#pragma once

#include <boost/config.hpp>

#include <boost/archive/detail/basic_iarchive.hpp>

#include <optional>
#include <boost/move/utility_core.hpp>

#include <boost/serialization/detail/is_default_constructible.hpp>
#include <boost/serialization/detail/stack_constructor.hpp>
#include <boost/serialization/force_include.hpp>
#include <boost/serialization/item_version_type.hpp>
#include <boost/serialization/level.hpp>
#include <boost/serialization/nvp.hpp>
#include <boost/serialization/split_free.hpp>
#include <boost/serialization/version.hpp>
#include <boost/type_traits/is_pointer.hpp>

// function specializations must be defined in the appropriate
// namespace - boost::serialization
namespace boost {
namespace serialization {

template <class Archive, class T>
void save(Archive& ar, const std::optional<T>& t, const unsigned int /*version*/
) {
// It is an inherent limitation to the serialization of optional.hpp
// that the underlying type must be either a pointer or must have a
// default constructor.  It's possible that this could change sometime
// in the future, but for now, one will have to work around it.  This can
// be done by serialization the optional<T> as optional<T *>
#if !defined(BOOST_NO_CXX11_HDR_TYPE_TRAITS)
    BOOST_STATIC_ASSERT(boost::serialization::detail::is_default_constructible<T>::value ||
                        boost::is_pointer<T>::value);
#endif
    const bool tflag = t.has_value();
    ar << boost::serialization::make_nvp("initialized", tflag);
    if (tflag) {
        ar << boost::serialization::make_nvp("value", *t);
    }
}

template <class Archive, class T>
void load(Archive& ar, std::optional<T>& t, const unsigned int version) {
    bool tflag;
    ar >> boost::serialization::make_nvp("initialized", tflag);
    if (!tflag) {
        t.reset();
        return;
    }

    if (0 == version) {
        boost::serialization::item_version_type item_version(0);
        boost::archive::library_version_type library_version(ar.get_library_version());
        if (boost::archive::library_version_type(3) < library_version) {
            ar >> BOOST_SERIALIZATION_NVP(item_version);
        }
    }
    if (!t.has_value())
        t = T();
    ar >> boost::serialization::make_nvp("value", *t);
}

template <class Archive, class T>
void serialize(Archive& ar, std::optional<T>& t, const unsigned int version) {
    boost::serialization::split_free(ar, t, version);
}

template <class T>
struct version<std::optional<T>> {
    BOOST_STATIC_CONSTANT(int, value = 1);
};

} // namespace serialization
} // namespace boost