sorting.js｜公告排序完整程式

const SORT_MODE_LABELS = {
  newest: '最新發布在前',
  oldest: '最舊發布在前',
  manual: '教師手動排序',
};

export const SORT_MODES = Object.keys(SORT_MODE_LABELS);

export function getSortModeLabel(mode) {
  return SORT_MODE_LABELS[mode] || SORT_MODE_LABELS.newest;
}

function timeValue(post) {
  const value = post.publish_at || post.published_at || post.updated_at || post.created_at;
  const time = value ? new Date(value).getTime() : 0;
  return Number.isNaN(time) ? 0 : time;
}

export function sortPosts(posts, mode = 'newest') {
  return [...posts].sort((a, b) => {
    const priorityDifference = Number(Boolean(b.pinned || b.locked)) - Number(Boolean(a.pinned || a.locked));
    if (priorityDifference !== 0) return priorityDifference;

    if (mode === 'manual') {
      return (a.sort_order || 0) - (b.sort_order || 0) || timeValue(b) - timeValue(a);
    }

    const timeDifference = timeValue(b) - timeValue(a);
    if (timeDifference !== 0) return mode === 'oldest' ? -timeDifference : timeDifference;
    return (a.sort_order || 0) - (b.sort_order || 0);
  });
}