Hookable.h

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// Copyright (c) 2025 Dave R. Smith.
// Malena Framework — Licensed under PolyForm Noncommercial 1.0.0; commercial use requires a paid license. See LICENSE.
 
#ifndef MALENA_HOOKABLE_H
#define MALENA_HOOKABLE_H
 
#include <Malena/Core/malena_export.h>
#include <Malena/Traits/Communication/Messenger.h>
#include <memory>
#include <type_traits>
 
namespace ml
{
    namespace detail
    {
        template<typename F> struct cb_arg;
        template<typename C, typename R, typename A>
        struct cb_arg<R(C::*)(A) const> { using type = std::decay_t<A>; };
        template<typename C, typename R, typename A>
        struct cb_arg<R(C::*)(A)>       { using type = std::decay_t<A>; };
    }
 
    template<typename F>
    using cb_arg_t = typename detail::cb_arg<decltype(&std::decay_t<F>::operator())>::type;

    struct MALENA_API Hookable : public ml::Messenger
    {
        virtual ~Hookable() = default;
 
        template<typename Enum>
        void sendHook(Enum hook) {
            sendMessage<Hookable*>(hook, this);
        }
 
        template<typename Enum, typename Callback>
        void onHook(Enum hook, Callback&& cb) {
            using T = cb_arg_t<Callback>;
            onMessage<Hookable*>(hook,
                [cb = std::forward<Callback>(cb)](Hookable* w) {
                    if constexpr (std::is_same_v<T, Hookable>) {
                        cb(*w);
                    } else {
                        if (auto* p = dynamic_cast<T*>(w))
                            cb(*p);
                    }
                }
            );
        }
    };
 
} // namespace ml
 
#endif // MALENA_HOOKABLE_H