from rest_framework.response import Response
from rest_framework.views import exception_handler


def agentfeed_exception_handler(exc, context):
    """DRF exception handler that additionally maps pathological-input crashes
    to a clean 400 instead of an unhandled 500.

    Deeply nested JSON in the request body raises RecursionError inside DRF's
    JSONParser (before any view validation runs). RecursionError subclasses
    RuntimeError, not ValueError, so DRF's default handler doesn't map it and
    it surfaces as a 500. Anything the default handler already knows about is
    left to it; anything still unhandled that isn't a RecursionError is
    returned as None so Django produces its normal 500.
    """
    response = exception_handler(exc, context)
    if response is not None:
        return response
    if isinstance(exc, RecursionError):
        return Response(
            {"detail": "Request payload is nested too deeply to parse."},
            status=400,
        )
    return None