import { getAccountRaw, LS } from "../lib/storage";
import { parsePositiveIntId } from "../lib/parseId";

// The Playlists module's selected-id seed, split out of PlaylistsProvider so its ?pl guard is
// unit-testable and the provider stays react-refresh-clean (component-only exports).
export function readSelectedId(): number | null {
  // A ?pl bookmark wins over the stored selection so a pasted link opens that playlist. BOTH must be a
  // positive-integer id (a bare "?pl=" gives Number("")===0, "?pl=1.5" a fractional id) — either would
  // select a non-existent playlist, so the stored fallback is guarded exactly like the URL.
  return (
    parsePositiveIntId(new URLSearchParams(window.location.search).get("pl")) ??
    parsePositiveIntId(getAccountRaw(LS.playlist))
  );
}