# coding=utf-8
"""
    @project: maxkb
    @Author：虎
    @file： rsa_util.py
    @date：2023/11/3 11:13
    @desc:
"""
import base64
import threading

from Crypto.Cipher import PKCS1_v1_5 as PKCS1_cipher
from Crypto.PublicKey import RSA
from django.core import cache
from django.db.models import QuerySet

from setting.models import SystemSetting, SettingType

lock = threading.Lock()
rsa_cache = cache.caches['default']
cache_key = "rsa_key"
# 对密钥加密的密码
secret_code = "mac_kb_password"


def generate():
    """
    生成 私钥秘钥对
    :return:{key:'公钥',value:'私钥'}
    """
    # 生成一个 2048 位的密钥
    key = RSA.generate(2048)

    # 获取私钥
    encrypted_key = key.export_key(passphrase=secret_code, pkcs=8,
                                   protection="scryptAndAES128-CBC")
    return {'key': key.publickey().export_key(), 'value': encrypted_key}


def get_key_pair():
    rsa_value = rsa_cache.get(cache_key)
    if rsa_value is None:
        lock.acquire()
        rsa_value = rsa_cache.get(cache_key)
        if rsa_value is not None:
            return rsa_value
        try:
            rsa_value = get_key_pair_by_sql()
            rsa_cache.set(cache_key, rsa_value)
        finally:
            lock.release()
    return rsa_value


def get_key_pair_by_sql():
    system_setting = QuerySet(SystemSetting).filter(type=SettingType.RSA.value).first()
    if system_setting is None:
        kv = generate()
        system_setting = SystemSetting(type=SettingType.RSA.value,
                                       meta={'key': kv.get('key').decode(), 'value': kv.get('value').decode()})
        system_setting.save()
    return system_setting.meta


# def get_key_pair():
#     if not os.path.exists("/opt/maxkb/conf/receiver.pem"):
#         kv = generate()
#         private_file_out = open("/opt/maxkb/conf/private.pem", "wb")
#         private_file_out.write(kv.get('value'))
#         private_file_out.close()
#         receiver_file_out = open("/opt/maxkb/conf/receiver.pem", "wb")
#         receiver_file_out.write(kv.get('key'))
#         receiver_file_out.close()
#     return {'key': open("/opt/maxkb/conf/receiver.pem").read(), 'value': open("/opt/maxkb/conf/private.pem").read()}


def encrypt(msg, public_key: str | None = None):
    """
    加密
    :param msg:        加密数据
    :param public_key: 公钥
    :return: 加密后的数据
    """
    if public_key is None:
        public_key = get_key_pair().get('key')
    cipher = PKCS1_cipher.new(RSA.importKey(public_key))
    encrypt_msg = cipher.encrypt(msg.encode("utf-8"))
    return base64.b64encode(encrypt_msg).decode()


def decrypt(msg, pri_key: str | None = None):
    """
    解密
    :param msg: 需要解密的数据
    :param pri_key: 私钥
    :return: 解密后数据
    """
    if pri_key is None:
        pri_key = get_key_pair().get('value')
    cipher = PKCS1_cipher.new(RSA.importKey(pri_key, passphrase=secret_code))
    decrypt_data = cipher.decrypt(base64.b64decode(msg), 0)
    return decrypt_data.decode("utf-8")