Function downloadAndMerge

src/lib/sync.ts:36–57

(userId: string)

// Download remote progress and replace local state with it
export async function downloadAndMerge(userId: string): Promise<boolean> {
  const { data, error } = await supabase
    .from("user_progress")
    .select("*")
    .eq("user_id", userId)
    .single();

  if (error || !data) {
    // No remote data yet — push local up
    await uploadProgress(userId);
    return false;
  }

  // Remote is the source of truth — overwrite local state
  saveCompleted(new Set<number>(data.completed ?? []));
  saveStarred(new Set<number>(data.starred ?? []));
  saveNotes((data.notes as Record<number, string>) ?? {});
  saveSolvedDates((data.solved_dates as Record<number, string>) ?? {});
  saveReminders((data.reminders as Record<number, Reminder>) ?? {});

  return true;
}

// Track when we last uploaded to ignore our own realtime events
let lastUploadAt = 0;