import hashlib


class PartitionedCache:

    def __init__(self, backend):
        self.backend = backend  # MinIO or local FS

    # -----------------------------
    # BUILD CACHE KEY
    # -----------------------------
    def key(self, action, target):

        base = f"{target.key()}:{action['hash']}"

        return hashlib.sha256(base.encode()).hexdigest()

    # -----------------------------
    # EXISTS
    # -----------------------------
    def exists(self, action, target):

        k = self.key(action, target)

        return self.backend.exists(k)

    # -----------------------------
    # STORE
    # -----------------------------
    def store(self, action, target, data):

        k = self.key(action, target)

        self.backend.put(k, data)

    # -----------------------------
    # FETCH
    # -----------------------------
    def fetch(self, action, target):

        k = self.key(action, target)

        return self.backend.get(k)