# -*- coding: utf-8 -*-

import hashlib
import os
from typing import Optional, Any

from passlib.context import CryptContext
from cryptography.hazmat.backends.openssl import backend
from cryptography.hazmat.primitives import padding
from cryptography.hazmat.primitives.ciphers import Cipher, algorithms, modes
from itsdangerous import URLSafeSerializer

from app.core.logger import logger


# 密码加密配置
PwdContext = CryptContext(
    schemes=["bcrypt"],
    deprecated="auto",
    bcrypt__rounds=12  # 设置加密轮数,增加安全性
)


class PwdUtil:
    """
    密码工具类,提供密码加密和验证功能
    """

    @classmethod
    def verify_password(cls, plain_password: str, password_hash: str) -> bool:
        """
        校验密码是否匹配

        Args:
            plain_password: 明文密码
            password_hash: 加密后的密码哈希值

        Returns:
            bool: 密码是否匹配
        """
        return PwdContext.verify(plain_password, password_hash)

    @classmethod 
    def set_password_hash(cls, password: str) -> str:
        """
        对密码进行加密

        Args:
            password: 明文密码

        Returns:
            str: 加密后的密码哈希值
        """
        return PwdContext.hash(password)

    @classmethod
    def check_password_strength(cls, password: str) -> Optional[str]:
        """
        检查密码强度

        Args:
            password: 明文密码

        Returns:
            str: 如果密码强度不够返回提示信息,否则返回None
        """
        if len(password) < 6:
            return "密码长度至少6位"
        if not any(c.isupper() for c in password):
            return "密码需要包含大写字母"
        if not any(c.islower() for c in password):
            return "密码需要包含小写字母" 
        if not any(c.isdigit() for c in password):
            return "密码需要包含数字"
        return None


class AESCipher:
    """AES 加密器"""

    def __init__(self, key: bytes | str) -> None:
        """
        初始化 AES 加密器

        :param key: 密钥，16/24/32 bytes 或 16 进制字符串
        :return:
        """
        self.key = key if isinstance(key, bytes) else bytes.fromhex(key)

    def encrypt(self, plaintext: bytes | str) -> bytes:
        """
        AES 加密

        :param plaintext: 加密前的明文
        :return:
        """
        if not isinstance(plaintext, bytes):
            plaintext = str(plaintext).encode('utf-8')
        iv = os.urandom(16)
        cipher = Cipher(algorithms.AES(self.key), modes.CBC(iv), backend=backend)
        encryptor = cipher.encryptor()
        padder = padding.PKCS7(cipher.algorithm.block_size).padder()  # type: ignore
        padded_plaintext = padder.update(plaintext) + padder.finalize()
        ciphertext = encryptor.update(padded_plaintext) + encryptor.finalize()
        return iv + ciphertext

    def decrypt(self, ciphertext: bytes | str) -> str:
        """
        AES 解密

        :param ciphertext: 解密前的密文，bytes 或 16 进制字符串
        :return:
        """
        ciphertext = ciphertext if isinstance(ciphertext, bytes) else bytes.fromhex(ciphertext)
        iv = ciphertext[:16]
        ciphertext = ciphertext[16:]
        cipher = Cipher(algorithms.AES(self.key), modes.CBC(iv), backend=backend)
        decryptor = cipher.decryptor()
        unpadder = padding.PKCS7(cipher.algorithm.block_size).unpadder()  # type: ignore
        padded_plaintext = decryptor.update(ciphertext) + decryptor.finalize()
        plaintext = unpadder.update(padded_plaintext) + unpadder.finalize()
        return plaintext.decode('utf-8')


class Md5Cipher:
    """MD5 加密器"""

    @staticmethod
    def encrypt(plaintext: bytes | str) -> str:
        """
        MD5 加密

        :param plaintext: 加密前的明文
        :return:
        """
        md5 = hashlib.md5()
        if not isinstance(plaintext, bytes):
            plaintext = str(plaintext).encode('utf-8')
        md5.update(plaintext)
        return md5.hexdigest()


class ItsDCipher:
    """ItsDangerous 加密器"""

    def __init__(self, key: bytes | str) -> None:
        """
        初始化 ItsDangerous 加密器

        :param key: 密钥，16/24/32 bytes 或 16 进制字符串
        :return:
        """
        self.key = key if isinstance(key, bytes) else bytes.fromhex(key)

    def encrypt(self, plaintext: Any) -> str:
        """
        ItsDangerous 加密

        :param plaintext: 加密前的明文
        :return:
        """
        serializer = URLSafeSerializer(self.key)
        try:
            ciphertext = serializer.dumps(plaintext)
        except Exception as e:
            logger.error(f'ItsDangerous encrypt failed: {e}')
            ciphertext = Md5Cipher.encrypt(plaintext)
        return ciphertext

    def decrypt(self, ciphertext: str) -> Any:
        """
        ItsDangerous 解密

        :param ciphertext: 解密前的密文
        :return:
        """
        serializer = URLSafeSerializer(self.key)
        try:
            plaintext = serializer.loads(ciphertext)
        except Exception as e:
            logger.error(f'ItsDangerous decrypt failed: {e}')
            plaintext = ciphertext
        return plaintext