/**
 * 会话列表卡片右上角相对时间（工作台「正在接诊」、在线接诊列表等共用）
 * @param {Object} item
 * @returns {string}
 */
export function formatSessionRelativeTime(item) {
	if (!item) return '';
	const t =
		item.last_message_time ||
		item.updated_at ||
		item.created_at ||
		item.register_time;
	if (t == null || t === '') return '';
	const ms = typeof t === 'number' ? (t > 1e12 ? t : t * 1000) : new Date(t).getTime();
	if (Number.isNaN(ms)) return '';
	const d = new Date(ms);
	const now = Date.now();
	const diff = Math.floor((now - ms) / 60000);
	if (diff < 1) return '刚刚';
	if (diff < 60) return `${diff}分钟前`;
	const h = Math.floor(diff / 60);
	if (h < 24) return `${h}小时前`;
	const pad = (n) => (n < 10 ? '0' + n : '' + n);
	return `${pad(d.getMonth() + 1)}-${pad(d.getDate())} ${pad(d.getHours())}:${pad(d.getMinutes())}`;
}