from typing import Optional


class AppException(Exception):
    """
    Base class for application specific exceptions that can also be used as API error responses.
    """
    code: str = 'unspecified_error'
    status_code: int = 400
    message: str

    def __init__(self, message: str, *, code: Optional[str] = None, status_code: Optional[int] = None):
        if code is not None:
            self.code = code
        if status_code is not None:
            self.status_code = status_code
        self.message = message

    def to_dict(self) -> dict:
        return {
            'code': self.code,
            'message': self.message,
        }