refactor: extract common handler logic into decorators

- Add @answer_callback for auto-answering callback queries
- Add @with_user_and_session for injecting user/session
- Add @require_state for state validation
- Reduce handlers.py from ~850 to ~540 lines

src/decorators.py

@@ -0,0 +1,76 @@
+from functools import wraps
+from typing import Callable
+
+from telegram import Update
+from telegram.ext import ContextTypes
+
+from src.database import (
+    User,
+    UserSession,
+    UserState,
+    get_or_create_user,
+    get_user_session,
+)
+
+INVALID_STATE_TEXT = "❌ Некорректное действие. Используйте /start для начала."
+
+
+def answer_callback(func: Callable) -> Callable:
+    """Автоматически отвечает на callback query."""
+
+    @wraps(func)
+    async def wrapper(
+        update: Update, context: ContextTypes.DEFAULT_TYPE, *args, **kwargs
+    ):
+        if update.callback_query:
+            await update.callback_query.answer()
+        return await func(update, context, *args, **kwargs)
+
+    return wrapper
+
+
+def with_user_and_session(func: Callable) -> Callable:
+    """Добавляет user и session в kwargs."""
+
+    @wraps(func)
+    async def wrapper(
+        update: Update, context: ContextTypes.DEFAULT_TYPE, *args, **kwargs
+    ):
+        user = get_or_create_user(update.effective_user.id)
+        session = get_user_session(user.id)
+        return await func(update, context, *args, user=user, session=session, **kwargs)
+
+    return wrapper
+
+
+def require_state(*states: UserState):
+    """Проверяет, что сессия в одном из указанных состояний."""
+
+    def decorator(func: Callable) -> Callable:
+        @wraps(func)
+        async def wrapper(
+            update: Update,
+            context: ContextTypes.DEFAULT_TYPE,
+            *args,
+            user: User,
+            session: UserSession | None,
+            **kwargs,
+        ):
+            if not session or session.state not in states:
+                if update.callback_query:
+                    await update.callback_query.edit_message_text(INVALID_STATE_TEXT)
+                elif update.message:
+                    await update.message.reply_text(INVALID_STATE_TEXT)
+                return
+            return await func(
+                update, context, *args, user=user, session=session, **kwargs
+            )
+
+        return wrapper
+
+    return decorator
+
+
+def require_states(*states: UserState):
+    """Алиас для require_state с несколькими состояниями."""
+    return require_state(*states)