import base64
import hashlib
import hmac
import json
import os
from datetime import datetime, timedelta
from typing import Any, Union, Optional
import jwt
from Crypto.Cipher import AES
from Crypto.Util.Padding import pad
from fastapi import HTTPException, status, Depends
from fastapi.security import OAuth2PasswordBearer
from passlib.context import CryptContext

from app import schemas
from app.core.config import settings
from cryptography.fernet import Fernet

pwd_context = CryptContext(schemes=["bcrypt"], deprecated="auto")
ALGORITHM = "HS256"

# Token认证
reusable_oauth2 = OAuth2PasswordBearer(
    tokenUrl=f"{settings.API_V1_STR}/login/access-token"
)


def create_access_token(
        subject: Union[str, Any], expires_delta: timedelta = None
) -> str:
    if expires_delta:
        expire = datetime.utcnow() + expires_delta
    else:
        expire = datetime.utcnow() + timedelta(
            minutes=settings.ACCESS_TOKEN_EXPIRE_MINUTES
        )
    to_encode = {"exp": expire, "sub": str(subject)}
    encoded_jwt = jwt.encode(to_encode, settings.SECRET_KEY, algorithm=ALGORITHM)
    return encoded_jwt


def verify_token(token: str = Depends(reusable_oauth2)) -> schemas.TokenPayload:
    try:
        payload = jwt.decode(
            token, settings.SECRET_KEY, algorithms=[ALGORITHM]
        )
        return schemas.TokenPayload(**payload)
    except (jwt.DecodeError, jwt.InvalidTokenError, jwt.ImmatureSignatureError):
        raise HTTPException(
            status_code=status.HTTP_403_FORBIDDEN,
            detail="token校验不通过",
        )


def get_token(token: str = None) -> str:
    """
    从请求URL中获取token
    """
    if token is None:
        raise HTTPException(
            status_code=status.HTTP_401_UNAUTHORIZED,
            detail="token请求参数缺失",
            headers={"WWW-Authenticate": "Bearer"},
        )
    return token


def verify_uri_token(token: str = Depends(get_token)) -> str:
    """
    通过依赖项使用token进行身份认证
    """
    if token != settings.API_TOKEN:
        raise HTTPException(
            status_code=status.HTTP_401_UNAUTHORIZED,
            detail="token校验不通过",
            headers={"WWW-Authenticate": "Bearer"},
        )
    return token


def verify_password(plain_password: str, hashed_password: str) -> bool:
    return pwd_context.verify(plain_password, hashed_password)


def get_password_hash(password: str) -> str:
    return pwd_context.hash(password)


def decrypt(data: bytes, key: bytes) -> Optional[bytes]:
    """
    解密二进制数据
    """
    fernet = Fernet(key)
    try:
        return fernet.decrypt(data)
    except Exception as e:
        print(str(e))
        return None


def encrypt_message(message: str, key: bytes):
    """
    使用给定的key对消息进行加密，并返回加密后的字符串
    """
    f = Fernet(key)
    encrypted_message = f.encrypt(message.encode())
    return encrypted_message.decode()


def hash_sha256(message):
    """
    对字符串做hash运算
    """
    return hashlib.sha256(message.encode()).hexdigest()


def aes_decrypt(data, key):
    """
    AES解密
    """
    if not data:
        return ""
    data = base64.b64decode(data)
    iv = data[:16]
    encrypted = data[16:]
    # 使用AES-256-CBC解密
    cipher = AES.new(key.encode('utf-8'), AES.MODE_CBC, iv)
    result = cipher.decrypt(encrypted)
    # 去除填充
    padding = result[-1]
    if padding < 1 or padding > AES.block_size:
        return ""
    result = result[:-padding]
    return result.decode('utf-8')


def aes_encrypt(data, key):
    """
    AES加密
    """
    if not data:
        return ""
    # 使用AES-256-CBC加密
    cipher = AES.new(key.encode('utf-8'), AES.MODE_CBC)
    # 填充
    padding = AES.block_size - len(data) % AES.block_size
    data += chr(padding) * padding
    result = cipher.encrypt(data.encode('utf-8'))
    # 使用base64编码
    return base64.b64encode(cipher.iv + result).decode('utf-8')


def nexusphp_encrypt(data_str: str, key):
    """
    NexusPHP加密
    """
    # 生成16字节长的随机字符串
    iv = os.urandom(16)
    # 对向量进行 Base64 编码
    iv_base64 = base64.b64encode(iv)
    # 加密数据
    cipher = AES.new(key, AES.MODE_CBC, iv)
    ciphertext = cipher.encrypt(pad(data_str.encode(), AES.block_size))
    ciphertext_base64 = base64.b64encode(ciphertext)
    # 对向量的字符串表示进行签名
    mac = hmac.new(key, msg=iv_base64 + ciphertext_base64, digestmod=hashlib.sha256).hexdigest()
    # 构造 JSON 字符串
    json_str = json.dumps({
        'iv': iv_base64.decode(),
        'value': ciphertext_base64.decode(),
        'mac': mac,
        'tag': ''
    })

    # 对 JSON 字符串进行 Base64 编码
    return base64.b64encode(json_str.encode()).decode()