from pathlib import PurePosixPath

from django.urls import reverse


def attachment_download_url(obj, request=None):
    """Never expose a storage URL: the download rechecks the request's ACL."""
    if not obj.attachment:
        return None
    url = reverse("api:v1:request-attachment-download", kwargs={"pk": obj.pk})
    return request.build_absolute_uri(url) if request else url


def attachment_filename(obj):
    return PurePosixPath(obj.attachment.name).name if obj.attachment else None