add notification center as apart of message passing

src/app/core/notification.h

@@ -0,0 +1,48 @@
+#ifndef YAZE_APP_CORE_NOTIFICATION_H
+#define YAZE_APP_CORE_NOTIFICATION_H
+
+#include <any>
+#include <string>
+#include <unordered_map>
+#include <vector>
+
+#include "app/core/message.h"
+
+namespace yaze {
+namespace app {
+namespace core {
+
+struct Notification : public Message {
+  Notification(const std::string& type, void* sender, std::any payload)
+      : Message{type, sender, payload} {}
+};
+
+class NotificationCenter {
+ public:
+  void AddObserver(const std::string& notificationType,
+                   IMessageListener* observer) {
+    observers[notificationType].push_back(observer);
+  }
+
+  void RemoveObserver(const std::string& notificationType,
+                      IMessageListener* observer) {
+    auto& observerList = observers[notificationType];
+    observerList.erase(
+        std::remove(observerList.begin(), observerList.end(), observer),
+        observerList.end());
+  }
+
+  void PostNotification(const Notification& notification) {
+    const auto& observerList = observers[notification.type];
+    for (auto observer : observerList) {
+      observer->onMessageReceived(notification);
+    }
+  }
+
+ private:
+  std::unordered_map<std::string, std::vector<IMessageListener*>> observers;
+};
+
+}  // namespace core
+}  // namespace app
+}  // namespace yaze