from datetime import datetime, timedelta, timezone
from jose import JWTError, jwt
from passlib.context import CryptContext
from fastapi.security import OAuth2PasswordBearer
from fastapi import Depends, HTTPException, status
from internal.models import TokenData, UserInDB, User
from internal.database import execute_query

# openssl rand -hex 32
SECRET_KEY = "e86c54c19962d562dab09081e5a6ce0c8ef49ac9a49cdb7135aa670707bbc894"
ALGORITHM = "HS256"
ACCESS_TOKEN_EXPIRE_MINUTES = 240

pwd_context = CryptContext(schemes=["bcrypt"], deprecated="auto")
oauth2_scheme = OAuth2PasswordBearer(tokenUrl="/users/token")

# 创建访问令牌
def create_access_token(data: dict, expires_delta: timedelta):
    to_encode = data.copy()
    expire = datetime.now(timezone.utc) + expires_delta
    to_encode.update({"exp": expire})
    encoded_jwt = jwt.encode(to_encode, SECRET_KEY, algorithm=ALGORITHM)
    return encoded_jwt

# 从数据库获取信息


def get_user(username: str):
    query = "SELECT * FROM users WHERE username = %s"
    result = execute_query(query, (username,), fetchall=False)
    if result:
        return UserInDB(**result)


async def get_current_user(token: str = Depends(oauth2_scheme)):
    credentials_exception = HTTPException(
        status_code=status.HTTP_401_UNAUTHORIZED,
        detail="Could not validate credentials",
        headers={"WWW-Authenticate": "Bearer"},
    )
    try:
        payload = jwt.decode(token, SECRET_KEY, algorithms=[ALGORITHM])
        username: str = payload.get("sub")
        if username is None:
            raise credentials_exception
        token_data = TokenData(username=username)
    except JWTError:
        raise credentials_exception
    user = get_user(username=token_data.username)
    if user is None:
        raise credentials_exception
    return user

# 验证用户是否为活跃用户


async def get_current_active_user(current_user: User = Depends(get_current_user)):
    if current_user.disabled:
        raise HTTPException(status_code=400, detail="Inactive user")
    return current_user

# 验证密码


def verify_password(plain_password, hashed_password):
    return pwd_context.verify(plain_password, hashed_password)

# 获取密码哈希


def get_password_hash(password):
    return pwd_context.hash(password)

# 验证用户密码


def authenticate_user(username: str, password: str):
    user = get_user(username)
    if not user:
        return False
    if not verify_password(password, user.hashed_password):
        return False
    return user