$(()=>{
  const ENDPOINT_URL = "https://school.one-way.dev/chtm/tableExporter/api~lesson-viewed";
  const STORAGE_PREFIX = 'tableExporter.lessonViewed.v1';

  function isLessonPage() {
    const href = window.location.href || '';
    return href.includes('/lesson/view') || href.includes('/lesson/webview');
  }

  function extractPageID() {
    let pageID = null;

    const searchParams = new URLSearchParams(window.location.search);
    if (searchParams.has('id')) {
      pageID = parseInt(searchParams.get('id'), 10);
      if (!isNaN(pageID)) return pageID;
    }

    const pathMatch = window.location.pathname.match(/(\\d+)/);
    if (pathMatch && pathMatch[1]) {
      pageID = parseInt(pathMatch[1], 10);
      if (!isNaN(pageID)) return pageID;
    }

    const hrefMatch = (window.location.href || '').match(/[\\?&]id=(\\d+)/);
    if (hrefMatch && hrefMatch[1]) {
      pageID = parseInt(hrefMatch[1], 10);
      if (!isNaN(pageID)) return pageID;
    }

    return null;
  }

  function getGcUserId() {
    try {
      const ui = window.userInfo || {};
      const candidates = [ui.id, ui.userId, ui.user_id, ui.gcId, ui.gc_id, window.accountUserId];
      for (const c of candidates) {
        const n = Number(c);
        if (!isNaN(n) && n > 0) return n;
      }
    } catch (e) {}
    return null;
  }

  async function sendViewed(gcId, lessonId) {
    try {
      await fetch(ENDPOINT_URL, {
        method: 'POST',
        credentials: 'include',
        headers: { 'Content-Type': 'application/json' },
        body: JSON.stringify({ gcId, lessonId })
      });
    } catch (e) {
      // noop
    }
  }

  if (!isLessonPage()) return;

  const lessonId = extractPageID();
  const gcId = getGcUserId();
  if (!lessonId || !gcId) return;

  const key = STORAGE_PREFIX + '.' + gcId + '.' + lessonId;
  try {
    if (localStorage.getItem(key)) return;
    localStorage.setItem(key, String(Date.now()));
  } catch (e) {}

  sendViewed(gcId, lessonId);
});