Messaging.h

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// File: Messaging.h
// Description: A system that holds a map of events and functions linked to events. It can call the functions linked to an event with a passed-in message 
// Author(s): Ori Balashov (ori.balashov@digipen.edu)
// 2025 / 10 / 22
// (C) Digipen 2025
//   ____   __                  __  __
// /\__  _\/\ \                /\ \/\ \
// \/_/\ \/\ \ \___      __    \ \ \_\ \    ___   __  __    ____     __
//    \ \ \ \ \  _ `\  /'__`\   \ \  _  \  / __`\/\ \/\ \  /',__\  /'__`\
//     \ \ \ \ \ \ \ \/\  __/    \ \ \ \ \/\ \L\ \ \ \_\ \/\__, `\/\  __/
//      \ \_\ \ \_\ \_\ \____\    \ \_\ \_\ \____/\ \____/\/\____/\ \____\
//       \/_/  \/_/\/_/\/____/     \/_/\/_/\/___/  \/___/  \/___/  \/____/
#pragma once
 
#include "Utility/MemberFunction.h"
#include "Framework/System.h"
 
namespace sys
{
class Messaging : public System
{
public:
#pragma region static_functions

    static auto getEnum() -> Type
    {
        return Type::Messaging;
    }

    static auto Broadcast(const std::string& eventName, const Message* message) -> std::vector<Message>;
 
#pragma endregion
 
    Messaging();
    ~Messaging() override             = default;
    Messaging(const Messaging& other) = default;
    Messaging(Messaging&& other) noexcept;
    auto operator=(const Messaging& other) -> Messaging&;
    auto operator=(Messaging&& other) noexcept -> Messaging& = default;
 
 
#pragma region overridden_functions
 
    auto clone() const -> std::unique_ptr<GameObject> override
    {
        return std::make_unique<Messaging>(*this);
    }
 
 
    auto onUpdate(float dt) -> void override;
    auto onRender() -> void override;
 
    auto endWindow() -> void override
    {
    }; // for debug ImGUI
    auto load(Stream& stream) -> void override;
    auto save(Stream& stream) const -> void override;
 
protected:
    auto systemShowMenu() -> void override;
 
public:
#pragma endregion
 
#pragma region Messaging_Functions
 
 
#pragma endregion

    template <typename classType>
    auto connect(
            const std::string& eventName,
            Message (classType::*functionToLink)(const Message*),
            const std::string& functionName,
            classType* pointerToSelf
            ) -> void
    {
        hlg::Debug("Messaging is connecting a function of name:{} to the event:{} with the owner"
                   ": {}::{}", functionName, eventName, pointerToSelf->getName(), pointerToSelf->getUUID());
        // Create a function that is the bound function pointer to the class instance
        std::function<Message(const Message*)> functionToCall = std::bind_front(functionToLink, pointerToSelf);
        // Create a Member Function with the bound function, function name, and a pointer to the owner
        th::MemberFunction<Message, const Message*> connectedFunction{functionToCall, functionName, pointerToSelf};
        // Attach the Member Function to the event
        functionMap.insert({eventName, connectedFunction});
    }

    auto remove(const std::string& functionToRemove, GameObject* owner) -> void;
 
    auto removeAll(const GameObject* owner) -> void;

    auto broadcast(const std::string& eventName, const Message* message) -> std::vector<Message>;
 
private:
#pragma region member_variables
    // The map that stores all functions linked to a map
    std::unordered_multimap<std::string, th::MemberFunction<Message, const Message*>> functionMap;
    //
#pragma endregion
 
#pragma region helper_functions
 
 
    // Lambda for checking if a message's owner doesn't exist anymore 
    inline static auto HasParentExpired = [](const auto& item)
    {
        const auto& [key, value] = item;
        return !value.hasValidOwner();
    };
 
#pragma endregion
 
};
}