with_latest_from.hpp

//                   ReactivePlusPlus library
// 
//           Copyright Aleksey Loginov 2022 - present.
//  Distributed under the Boost Software License, Version 1.0.
//     (See accompanying file LICENSE_1_0.txt or copy at
//           https://www.boost.org/LICENSE_1_0.txt)
// 
//  Project home: https://github.com/victimsnino/ReactivePlusPlus
 
#pragma once
 
#include <rpp/observables/details/member_overload.hpp>
#include <rpp/observables/constraints.hpp>
#include <rpp/utils/functors.hpp>
#include <rpp/utils/function_traits.hpp>
 
 
#include <tuple>
 
namespace rpp::details
{
struct with_latest_from_tag;
}
 
namespace rpp::details
{
template<constraint::decayed_type Type, typename TSelector, constraint::observable ...TObservables>
struct with_latest_from_impl;
 
template<constraint::decayed_type Type, typename SpecificObservable>
struct member_overload<Type, SpecificObservable, with_latest_from_tag>
{
    template<constraint::observable ...TObservables, std::invocable<Type, utils::extract_observable_type_t<TObservables>...> TSelector>
    auto with_latest_from(TSelector&& selector, TObservables&&...observables) const& requires is_header_included<with_latest_from_tag, TObservables...>
    {
        return static_cast<const SpecificObservable*>(this)->template lift<utils::decayed_invoke_result_t<TSelector, Type, utils::extract_observable_type_t<TObservables>...>>(with_latest_from_impl<Type, std::decay_t<TSelector>, std::decay_t<TObservables>...>{std::forward<TSelector>(selector), { std::forward<TObservables>(observables)... }});
    }
 
    template<constraint::observable ...TObservables, std::invocable<Type, utils::extract_observable_type_t<TObservables>...> TSelector>
    auto with_latest_from(TSelector&& selector, TObservables&&...observables) && requires is_header_included<with_latest_from_tag, TObservables...>
    {
        return std::move(*static_cast<SpecificObservable*>(this)).template lift<utils::decayed_invoke_result_t<TSelector, Type, utils::extract_observable_type_t<TObservables>...>>(with_latest_from_impl<Type, std::decay_t<TSelector>, std::decay_t<TObservables>...>{std::forward<TSelector>(selector), { std::forward<TObservables>(observables)... }});
    }
 
    template<constraint::observable ...TObservables>
    auto with_latest_from(TObservables&&...observables) const& requires is_header_included<with_latest_from_tag, TObservables...>
    {
        return static_cast<const SpecificObservable*>(this)->with_latest_from(utils::pack_to_tuple{}, std::forward<TObservables>(observables)...);
    }
 
    template<constraint::observable ...TObservables>
    auto with_latest_from(TObservables&&...observables) && requires is_header_included<with_latest_from_tag, TObservables...>
    {
        return std::move(*static_cast<SpecificObservable*>(this)).with_latest_from(utils::pack_to_tuple{}, std::forward<TObservables>(observables)...);
    }
};
} // namespace rpp::details