Task: Progressive Depth Levels

# src/managers/user_manager.py
class UserManager:
    """Manages user service lifecycle and dependencies"""

    def __init__(self, db_connection, cache_client, logger):
        self.db = db_connection
        self.cache = cache_client
        self.logger = logger
        self.service = None

    def get_service(self):
        """Lazy initialization of UserService with all dependencies"""
        if self.service is None:
            self.service = UserService(
                db=self.db,
                cache=self.cache,
                logger=self.logger
            )
        return self.service

    def reset(self):
        """Reset service instance for testing"""
        self.service = None


# src/services/user_service.py
class UserService:
    def __init__(self, db, cache, logger):
        self.db = db
        self.cache = cache
        self.logger = logger

    def get_user(self, user_id):
        cached = self.cache.get(f"user:{user_id}")
        if cached:
            return cached

        user = self.db.query("SELECT * FROM users WHERE id = ?", [user_id])
        self.cache.set(f"user:{user_id}", user)
        return user