import base64
import hashlib
import json
import logging

logger = logging.getLogger(__name__)


def decrypt_jd_message(encrypted_body: str, app_secret: str) -> dict | None:
    try:
        key = hashlib.md5(app_secret.encode("utf-8")).hexdigest()[:16].encode("utf-8")
        raw = base64.b64decode(encrypted_body)

        iv = raw[:16]
        ciphertext = raw[16:]

        from Crypto.Cipher import AES

        cipher = AES.new(key, AES.MODE_CBC, iv)
        decrypted = cipher.decrypt(ciphertext)

        pad_len = decrypted[-1]
        decrypted = decrypted[:-pad_len]

        return json.loads(decrypted.decode("utf-8"))
    except Exception:
        logger.warning("JD message AES decrypt failed")
        return None