init

src/usecase/get_user.py

@@ -0,0 +1,18 @@
+import uuid
+from typing import TYPE_CHECKING
+
+from src import domain, dto
+
+if TYPE_CHECKING:
+    from src.usecase.usecase import Usecase
+
+
+async def get_user(self: 'Usecase', user_id: uuid.UUID) -> dto.GetUserOutput:
+    user: domain.User | None = await self.database.get_user(user_id=user_id)
+    if user is None:
+        raise domain.UserNotFound(user_id)
+
+    return dto.GetUserOutput(
+        user_id=user.id,
+        name=user.name,
+    )

src/usecase/notify_user.py

@@ -0,0 +1,22 @@
+import uuid
+from typing import TYPE_CHECKING
+
+from src import domain
+
+if TYPE_CHECKING:
+    from src.usecase.usecase import Usecase
+
+
+async def notify_user(self: 'Usecase', user_id: uuid.UUID, chat_id: int, message: str) -> None:
+    """Send notification to user via Telegram"""
+    if self.telegram_writer is None:
+        raise RuntimeError('TelegramWriter not configured')
+
+    # Get user from database
+    user = await self.database.get_user(user_id)
+    if user is None:
+        raise domain.UserNotFound(user_id)
+
+    # Send personalized message
+    text = f'Привет, {user.name}!\n\n{message}'
+    await self.telegram_writer.send_message(chat_id=chat_id, text=text)

src/usecase/usecase.py

@@ -0,0 +1,25 @@
+import uuid
+from dataclasses import dataclass
+from typing import Protocol
+
+from src import domain
+
+from .get_user import get_user
+from .notify_user import notify_user
+
+
+class Database(Protocol):
+    async def get_user(self, user_id: uuid.UUID) -> domain.User | None: ...
+
+
+class TelegramWriter(Protocol):
+    async def send_message(self, chat_id: int, text: str) -> None: ...
+
+
+@dataclass
+class Usecase:
+    database: Database
+    telegram_writer: TelegramWriter
+
+    get_user = get_user
+    notify_user = notify_user