chore: Code refactoring and improvements

app/filters/user.py

@@ -0,0 +1,27 @@
+__all__ = ("Unregistered", "Registered", "RegisteredCallback")
+
+from aiogram.filters import Filter
+from aiogram.types import CallbackQuery, Message
+
+from app.models.user import User
+
+
+class Unregistered(Filter):
+    async def __call__(self, message: Message) -> bool:
+        if message.from_user is None:
+            return False
+
+        return not User.user_by_telegram_id_exist(message.from_user.id)
+
+
+class Registered(Filter):
+    async def __call__(self, message: Message) -> bool:
+        if message.from_user is None:
+            return False
+
+        return User.user_by_telegram_id_exist(message.from_user.id)
+
+
+class RegisteredCallback(Filter):
+    async def __call__(self, callback: CallbackQuery) -> bool:
+        return User.user_by_telegram_id_exist(callback.from_user.id)