import base64
import hashlib
from contextlib import suppress
# from Cryptodome.Cipher import AES

class Decrypt :
    def __init__(self, aid, episodeId, timestamp, nonce, userId, zid):
        self._aid = aid
        self._episodeId = episodeId
        self._timestamp = timestamp
        self._nonce = nonce
        self._userId = userId
        self._zid = zid
    
    @classmethod
    def get_aes(cls):
        with suppress(AttributeError):
            return cls.AES
        try:
            from Crypto.Cipher import AES
        except ImportError:
            raise ImportError("Missing optional dependency 'pycryptodomex'. Please install it to use this functionality.")
        
        cls.AES = AES
        return cls.AES

    @classmethod
    def _decrypt(cls, data: bytes, key: bytes, iv: bytes) -> bytes:
        AES = cls.get_aes()
        cipher = AES.new(key, AES.MODE_CBC, iv)
        return cipher.decrypt(data)

    def get_decrypt_infomations(self) -> tuple[bytes, bytes]:
        
        temp_key = hashlib.sha256(f"{self._userId}{self._episodeId}{self._timestamp}".encode()).digest()
        temp_iv = hashlib.sha256(f"{self._nonce}{self._timestamp}".encode()).digest()[:16]
        encrypted_key = base64.b64decode(self._aid)
        encrypted_iv = base64.b64decode(self._zid)

        key = self._decrypt(encrypted_key, temp_key, temp_iv)[:16]
        iv = self._decrypt(encrypted_iv, temp_key, temp_iv)[:16]
        return key, iv