case_4.h

//
// Created by belov on 14.07.2026.
//

#pragma once


namespace case_4 {
    template <typename A>
    consteval bool has_annotation(std::meta::info info) {
        return not std::meta::annotations_of_with_type(info, ^^A).empty();
    }

    struct Component {};

    namespace some_dir {
        class [[=Component{}]] D1 {
            public:
            void run() {}
        };

        class [[=Component{}]] D2 {
            public:
            void run() {}
        };

        class D3 {
        public:
            void run() {}
        };
    }

    void case_4() {
        constexpr auto ctx = std::meta::access_context::current();
        static constexpr auto classList = std::define_static_array(std::meta::members_of(^^some_dir, ctx));

        static_assert(classList.size() == 3);
        template for (constexpr auto obj : classList) {
            static_assert(std::meta::is_class_type(obj));
        }

        auto getAnnotatedClassListSize = [&]() consteval -> auto {
            std::size_t t = 0;
            template for (constexpr auto obj : classList) {
                if (has_annotation<Component>(obj))
                    t += 1;
            }
            return t;
        };

        auto getAnnotatedClassList = [&]() consteval -> auto {
            constexpr auto size = getAnnotatedClassListSize();
            std::size_t c = 0;
            std::array<std::meta::info, size> array{};
            template for (constexpr auto obj : classList) {
                if (has_annotation<Component>(obj))
                    array[c++] = obj;
            }
            return array;
        };

        constexpr auto annotatedClassList = getAnnotatedClassList();
        static_assert(annotatedClassList == std::array<std::meta::info, 2>{^^some_dir::D1, ^^some_dir::D2});
    }
}