class FirestoreStore:
    def __init__(self, project_id, collection="measures"):
        from google.cloud import firestore  # import tardif : optionnel

        self.db = firestore.Client(project=project_id)
        self.collection = collection

    def add_measure(self, measure):
        self.db.collection(self.collection).add(measure)

    def list_measures(self, device_id, limit=50):
        docs = (
            self.db.collection(self.collection)
            .where("device_id", "==", device_id)
            .limit(limit)
            .stream()
        )
        return [d.to_dict() for d in docs]