The Split-Brain Cache Lease

"""
User Profile Service
Handles profile updates and transactional database operations.
"""

class UserProfileService:
    def __init__(self, db, cache):
        self.db = db
        self.cache = cache

    def update_email(self, user_id, new_email):
        # AI Attempt: Invalidate cache before committing to DB
        self.cache.invalidate(f"user:{user_id}")
        self.db.begin_transaction()
        self.db.update_user(user_id, {"email": new_email})
        self.db.commit()
        return {"user_id": user_id, "email": new_email, "status": "updated"}

    def get_profile(self, user_id):
        key = f"user:{user_id}"
        cached = self.cache.get(key)
        if cached is not None:
            return {"data": cached, "source": "cache"}

        lease = self.cache.acquire_lease(key)
        db_user = self.db.get_user(user_id)
        stored = self.cache.set_with_lease(key, db_user, lease["token"])
        return {"data": db_user, "source": "db_loader", "stored": stored}