event_listener.hpp

#pragma once
#include <functional>
#include <any>
#include <unordered_map>
#include <deque>
 
namespace atlas::event {
 
    template<typename UEvent>
    class listener {
        using event = std::function<void(UEvent&)>;
 
    public:
        listener() = default;
 
        template<typename UObject, typename UCallback>
        void subscribe(UObject* p_instance, const UCallback& p_callback) {
            m_event_handlers.push_back(
              [p_instance, p_callback](UEvent& p_event) {
                  (p_instance->*p_callback)(p_event);
              });
        }
 
        // Notify all subscribers to this particular event listener
        void notify_all(UEvent& p_event) {
            for (const auto& callback : m_event_handlers) {
                callback(p_event);
            }
        }
 
    private:
        std::deque<event> m_event_handlers;
    };
};