from cryptography.fernet import Fernet


class TokenCipher:
    """Шифрует OAuth-токены перед передачей в БД."""

    def __init__(self, key: str) -> None:
        try:
            self._fernet = Fernet(key.encode("ascii"))
        except (ValueError, UnicodeEncodeError) as error:
            raise RuntimeError("TOKEN_ENCRYPTION_KEY is invalid") from error

    def encrypt(self, value: str) -> bytes:
        return self._fernet.encrypt(value.encode("utf-8"))