"""User repository for data access operations."""
from typing import Optional
from sqlalchemy.orm import Session
from backend.models.user import User
from backend.repositories.base import BaseRepository


class UserRepository(BaseRepository[User]):
    """Repository for User model operations."""

    def __init__(self, db: Session):
        """Initialize user repository."""
        super().__init__(User, db)

    def get_by_username(self, username: str) -> Optional[User]:
        """Get a user by username."""
        return self.db.query(User).filter(User.username == username).first()