import { isEmpty } from '@ember/utils';

//
// Derives a stable grouping key for a contribution, so that contributions
// created for the same issue/pull request (one per contributor) can be
// linked together in the UI.
//
// The bot writes the exact same `url` string (the html_url of the issue/PR)
// into every per-contributor IPFS document for a given piece of work, so the
// top-level `url` field on the model is sufficient as a grouping key. Manual
// contributions without a URL return null and are treated as singletons.
//
export default function contributionGroupingKey (contribution) {
  let url = contribution ? contribution.url : null;
  if (isEmpty(url)) return null;
  return url;
}