class user_util():

    def get_user_id(token):
        db = dataset.connect('mysql://choozmo:pAssw0rd@db.ptt.cx:3306/AI_anchor?charset=utf8mb4')
        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 = models.TokenData(username=username)
        except JWTError:
            raise credentials_exception
        user = get_user(username=token_data.username)
        if user is None:
            raise credentials_exception
        user_id = first(db.query('SELECT * FROM users where username="' + user.username+'"'))['id']
        return user_id

    def check_user_exists(username):
        db = dataset.connect('mysql://choozmo:pAssw0rd@db.ptt.cx:3306/AI_anchor?charset=utf8mb4')
        if int(next(iter(db.query('SELECT COUNT(*) FROM AI_anchor.users WHERE username = "'+username+'"')))['COUNT(*)']) > 0:
            return True
        else:
            return False

    def get_user(username: str):
        db = dataset.connect('mysql://choozmo:pAssw0rd@db.ptt.cx:3306/AI_anchor?charset=utf8mb4')
        if not check_user_exists(username):  # if user don't exist
            return False
        user_dict = next(
            iter(db.query('SELECT * FROM AI_anchor.users where username ="'+username+'"')))
        user = models.User(**user_dict)
        return user
        
    def user_register(user):
        db = dataset.connect('mysql://choozmo:pAssw0rd@db.ptt.cx:3306/AI_anchor?charset=utf8mb4')
        table = db['users']
        user.password = get_password_hash(user.password)
        table.insert(dict(user))

    def get_password_hash(password):
        return pwd_context.hash(password)
    def verify_password(plain_password, hashed_password):
        return pwd_context.verify(plain_password, hashed_password)
    def authenticate_user(username: str, password: str):
        db = dataset.connect('mysql://choozmo:pAssw0rd@db.ptt.cx:3306/AI_anchor?charset=utf8mb4')
        if not check_user_exists(username):  # if user don't exist
            return False
        user_dict = next(iter(db.query('SELECT * FROM AI_anchor.users where username ="'+username+'"')))
        user = models.User(**user_dict)
        if not verify_password(password, user.password):
            return False
        return user