# -*- coding: utf-8 -*-
"""统一应用异常与错误响应。

FastAPI 依赖里无法直接「返回响应短路」，因此用抛出 AppError + 全局异常处理器
的方式，产出与 Flask 侧同形的 JSON 包体（{status, success, message, error_code}）。
"""
from typing import Any

from fastapi import Request
from fastapi.exceptions import RequestValidationError
from starlette.exceptions import HTTPException as StarletteHTTPException

from web.response import error


class AppError(Exception):
    """业务异常：携带 HTTP 状态码与可选 error_code。"""

    def __init__(self, message: str, status_code: int = 400, error_code: str | None = None):
        super().__init__(message)
        self.message = message
        self.status_code = status_code
        self.error_code = error_code


def install_error_handlers(app) -> None:
    @app.exception_handler(AppError)
    async def _app_error(_request: Request, exc: AppError):
        return error(exc.message, exc.status_code, exc.error_code)

    @app.exception_handler(StarletteHTTPException)
    async def _http_error(_request: Request, exc: StarletteHTTPException) -> Any:
        # 404/405 等也统一为本站包体（Flask 侧 404 返回 {'success': False, ...}）
        msg = {404: '请求的资源不存在', 405: '请求方法不允许'}.get(exc.status_code,
                                                             str(exc.detail or '请求错误'))
        return error(msg, exc.status_code)

    @app.exception_handler(RequestValidationError)
    async def _validation_error(_request: Request, exc: RequestValidationError):
        return error('请求参数错误', 400)