"""全局异常 + 统一错误响应。"""

from fastapi import FastAPI, Request, status
from fastapi.responses import JSONResponse


class AppError(Exception):
    """业务异常基类。子类在各域 exceptions.py 中定义。"""

    status_code: int = status.HTTP_400_BAD_REQUEST
    detail: str = "bad request"

    def __init__(self, detail: str | None = None):
        self.detail = detail or self.detail
        super().__init__(self.detail)


class NotFoundError(AppError):
    status_code = status.HTTP_404_NOT_FOUND
    detail = "not found"


def register_exception_handlers(app: FastAPI) -> None:
    @app.exception_handler(AppError)
    async def app_error_handler(_: Request, exc: AppError) -> JSONResponse:
        return JSONResponse(status_code=exc.status_code, content={"detail": exc.detail})