/**
 * AKSRT Enhancements — 全局 UI 增强
 *
 * 图片灯箱由 assets/js/runtime/imgbox.js（Miniimgbox，zibll 风格）唯一负责，
 * 此文件仅保留滚动方向感知的 legacy class 同步。
 *
 * @package AKSRT
 */

(function () {
  'use strict';

  var initialized = false;

  /* ============================================================
   * 滚动方向感知
   * Scroll direction is owned by runtime main.js body scroll bus
   * (body.scroll-down / body.scroll-up / body.body-scroll).
   * This stub syncs the legacy aksrt-* prefixed classes for backward compat.
   * ============================================================ */
  function initScrollDirection() {
    var body = document.body;

    function sync() {
      body.classList.toggle('aksrt-body-scroll', body.classList.contains('body-scroll'));
      body.classList.toggle('aksrt-scroll-down', body.classList.contains('scroll-down'));
      body.classList.toggle('aksrt-scroll-up', body.classList.contains('scroll-up'));

      body.classList.add('aksrt-scrolling');
      clearTimeout(body._aksrtScrollTimer);
      body._aksrtScrollTimer = setTimeout(function () {
        body.classList.remove('aksrt-scrolling');
      }, 300);
    }

    function onScroll() {
      requestAnimationFrame(sync);
    }

    window.addEventListener('scroll', onScroll, { passive: true });
  }

  /* ============================================================
   * 初始化入口 — 只执行一次（window scroll 绑定不可重复）
   * ============================================================ */
  function init() {
    if (initialized) return;
    initialized = true;
    initScrollDirection();
  }

  if (document.readyState === 'loading') {
    document.addEventListener('DOMContentLoaded', init);
  } else {
    init();
  }

})();