import json

from sqlalchemy.types import TypeDecorator, LargeBinary

from community_qa_bot.settings import SECRET_KEY
from community_qa_bot.aes import AESCipher


def get_aes_key() -> bytes:
    return SECRET_KEY.encode()[:32]


class AESEncryptedColumn(TypeDecorator):
    impl = LargeBinary

    def process_bind_param(self, value, dialect):
        if value is not None:
            json_str = json.dumps(value)
            return AESCipher(get_aes_key()).encrypt(json_str)
        return value

    def process_result_value(self, value, dialect):
        if value is not None:
            json_str = AESCipher(get_aes_key()).decrypt(value)
            return json.loads(json_str)
        return value