import base64

import boto3
from fansifter_common.utils.functional import lazy_proxy

from app.config import settings

_client = lazy_proxy(
    lambda: boto3.client(
        "kms",
        region_name=settings.aws_region_name,
    ),
)


def decrypt(ciphertext: str) -> str:
    response = _client.decrypt(
        CiphertextBlob=base64.b64decode(ciphertext),
        KeyId=settings.kms_key_arn,
        EncryptionContext={"field": "token"},
    )
    return response["Plaintext"].decode()