from __future__ import annotations

import base64
import hashlib

from cryptography.fernet import Fernet, InvalidToken


def make_fernet(encryption_key: str) -> Fernet:
    digest = hashlib.sha256(encryption_key.encode("utf-8")).digest()
    key = base64.urlsafe_b64encode(digest)
    return Fernet(key)


def encrypt_token(encryption_key: str, plaintext: str) -> str:
    return make_fernet(encryption_key).encrypt(plaintext.encode("utf-8")).decode("ascii")


def decrypt_token(encryption_key: str, ciphertext: str) -> str | None:
    try:
        return make_fernet(encryption_key).decrypt(ciphertext.encode("ascii")).decode("utf-8")
    except InvalidToken:
        return None