from __future__ import annotations

from typing import Any

from fastapi import FastAPI, Request
from fastapi.exceptions import RequestValidationError
from fastapi.responses import JSONResponse
from starlette.exceptions import HTTPException as StarletteHTTPException


class APIError(Exception):
    def __init__(
        self,
        status_code: int,
        code: str,
        message: str,
        detail: Any | None = None,
    ) -> None:
        super().__init__(message)
        self.status_code = status_code
        self.code = code
        self.message = message
        self.detail = detail


def error_payload(code: str, message: str, detail: Any | None = None) -> dict[str, Any]:
    payload: dict[str, Any] = {"code": code, "message": message}
    if detail is not None:
        payload["detail"] = detail
    return payload


def install_exception_handlers(app: FastAPI) -> None:
    @app.exception_handler(APIError)
    async def api_error_handler(_: Request, exc: APIError) -> JSONResponse:
        return JSONResponse(
            status_code=exc.status_code,
            content=error_payload(exc.code, exc.message, exc.detail),
        )

    @app.exception_handler(RequestValidationError)
    async def validation_error_handler(
        _: Request, exc: RequestValidationError
    ) -> JSONResponse:
        return JSONResponse(
            status_code=422,
            content=error_payload("validation_error", "请求参数校验失败", exc.errors()),
        )

    @app.exception_handler(StarletteHTTPException)
    async def http_error_handler(_: Request, exc: StarletteHTTPException) -> JSONResponse:
        detail = exc.detail
        if isinstance(detail, dict) and "code" in detail:
            return JSONResponse(status_code=exc.status_code, content=detail)
        return JSONResponse(
            status_code=exc.status_code,
            content=error_payload("http_error", str(detail)),
        )