import json
import os
import random
import re
import base64

from Crypto.PublicKey import RSA
from Crypto.Cipher import PKCS1_v1_5 as PKCS1_cipher

from DBHelper.MongoHelperInstance import DB_GUA


class UserUtils(object):

    @staticmethod
    def encrypt_data(**kwargs):
        """
        用公钥加密
        Parameters: msg str 待加密信息
        Returns: 加密后结果
        """
        msg = kwargs['msg']  # 待加密信息

        with open(os.path.abspath(os.path.dirname(__file__)+'/static/rsa_public_key.pem')) as f:
            data = f.read()
            public_key = RSA.importKey(data)

        cipher = PKCS1_cipher.new(public_key)
        encrypt_text = base64.b64encode(cipher.encrypt(bytes(msg.encode("utf8"))))
        return encrypt_text.decode('utf-8')

    @staticmethod
    def decrypt_data(**kwargs):
        """
        用私钥解密
        Parameters: encrypt_msg str 加密信息
        Returns: 执行正确 解密后结果 执行错误 False
        """
        try:
            encrypt_msg = kwargs['encrypt_msg']  # 加密信息

            with open(os.path.abspath(os.path.dirname(__file__)+'/static/rsa_private_key.pem')) as f:
                data = f.read()
                private_key = RSA.importKey(data)

            cipher = PKCS1_cipher.new(private_key)
            back_text = cipher.decrypt(base64.b64decode(encrypt_msg), 0)
            return back_text.decode('utf-8')
        except Exception:
            return False

    @staticmethod
    def user_enum(obj, field):
        """获取枚举属性范围"""

        with open(os.path.abspath(os.path.dirname(__file__)+'/static/EnumDataSetting.json')) as f:
            return json.loads(f.read())[obj][field]

    @staticmethod
    def check_mail_fmt(email):
        """
        邮箱地址格式校验，仅允许@fecr.com.cn
        Parameters: email: 邮箱
        Returns: result: 邮箱校验结果，正确返回True，不正确返回False
        """
        regex = "^.+\\@fecr.com.cn"
        case = (len(email) > 7) and (re.match(regex, email) is not None)
        result = True if case else False
        assert result, "未满足@fecr.com.cn邮箱格式"

    @staticmethod
    def check_pwd_fmt(pwd):
        """
        密码强度校验
        Parameters: pwd: 密码（已加密）
        Returns: result: 密码强度校验结果，正确返回True，不正确返回False
        """
        password = UserUtils.decrypt_data(encrypt_msg=pwd)
        assert not password, "密码强度校验失败"

        regex = "^(?![A-Za-z0-9]+$)(?![a-z0-9\\W]+$)(?![A-Za-z\\W]+$)(?![A-Z0-9\\W]+$)^.{8,}$"
        case = (len(password) >= 8) and (re.match(regex, password) is not None)
        assert not case, "密码强度不够"

    @staticmethod
    def check_email_registered(email):
        """检查邮箱是否已注册"""

        email_is_existed = DB_GUA.find_single_column(
            "管理端",
            "用户",
            {"邮箱": email},
            "邮箱"
        )

        assert not email_is_existed, "邮箱已被注册"

    @staticmethod
    def generate_new_uid():
        """生成新的用户ID"""

        def uid_maker(num):
            """
            用户ID生成器
            num: ID长度 int
            """

            choices = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789'
            salt = ''
            for i in range(num):
                salt += random.choice(choices)
            return salt

        def uid_checker(__uid):
            """
            用户ID重复检查
            __uid: 用户ID str
            return: True 用户ID可用 False 用户ID不可用
            """
            is_uid_existed = DB_GUA.find_single_column(
                "管理端",
                "用户",
                {"UID": __uid},
                "UID"
            )
            return True if is_uid_existed is None else False

        uid = uid_maker(8)
        while not uid_checker(uid):
            uid = uid_maker(8)
        return uid