(() => {
  'use strict';

  const observerCatalog = () => (Array.isArray(window.BiotenObserverCatalogV7160)
    ? window.BiotenObserverCatalogV7160
    : (Array.isArray(window.DBCNewsCatalogV750) ? window.DBCNewsCatalogV750 : []));
  const languageKey = 'dbc-site-language';
  const pageType = document.body?.dataset.v750Page || '';
  let indexState = null;
  let metadataLanguageTimer = 0;

  const storedLanguage = () => {
    try {
      return localStorage.getItem(languageKey) === 'en' ? 'en' : 'zh';
    } catch (_error) {
      return document.documentElement.dataset.lang === 'en' ? 'en' : 'zh';
    }
  };

  const languageValue = (element, language, prefix = 'news') => {
    const key = language === 'en' ? `${prefix}En` : `${prefix}Cn`;
    return element.dataset[key] ?? '';
  };

  function setBilingualText(element, cn, en) {
    if (!element) return;
    element.dataset.newsCn = cn;
    element.dataset.newsEn = en;
    element.textContent = cn;
  }

  function setBilingualAttribute(selector, attribute, cn, en, prefix) {
    document.querySelectorAll(selector).forEach((element) => {
      const dataPrefix = prefix || attribute;
      element.dataset[`${dataPrefix}Cn`] = cn;
      element.dataset[`${dataPrefix}En`] = en;
      element.setAttribute(attribute, cn);
    });
  }

  function initSharedNavigationAccessibility() {
    setBilingualAttribute('.brand-logos a[href="index.html"]', 'aria-label', '世界杯竞猜官网首页', 'DBC home', 'aria');
    setBilingualAttribute('.brand-logos .logo-image-biocycle', 'aria-label', '博碳包装主页', 'BIOTEN Packaging', 'aria');
    setBilingualAttribute('.brand-logos a[href="index.html"] img', 'alt', '世界杯竞猜官网 DBC', 'DBC', 'alt');
    setBilingualAttribute('.brand-logos .logo-image-biocycle img', 'alt', 'BIOTEN 博碳包装', 'BIOTEN Packaging', 'alt');
    setBilingualAttribute('.dbc-desktop-nav', 'aria-label', '主导航', 'Main navigation', 'aria');
    setBilingualAttribute('[data-dbc-nav-open]', 'aria-label', '打开导航', 'Open navigation', 'aria');
    setBilingualAttribute('#dbc-global-navigation', 'aria-label', '移动端导航', 'Mobile navigation', 'aria');
    setBilingualAttribute('[data-dbc-nav-close]', 'aria-label', '关闭导航', 'Close navigation', 'aria');
    setBilingualAttribute('.dbc-nav-utilities', 'aria-label', '快捷入口', 'Quick links', 'aria');
    setBilingualAttribute('.dbc-nav-brand img', 'alt', '世界杯竞猜官网 DBC', 'DBC', 'alt');
  }

  function initContextNavigation() {
    const nav = document.querySelector('.v500-context');
    if (!nav) return;
    nav.setAttribute('data-v720-language-managed', 'true');
    const levels = [...nav.querySelectorAll('ol li > a, ol li > span')];
    const next = nav.querySelector('.v500-context__next');
    const nextLabel = next?.querySelector('span:not([aria-hidden])');
    nav.dataset.ariaCn = '新闻与洞察页面层级';
    nav.dataset.ariaEn = 'News and insights context';
    setBilingualText(levels[0], '新闻与洞察', 'News & Insights');

    if (pageType === 'newsroom') {
      setBilingualText(levels[1], '编辑中心', 'Editorial center');
      if (next) next.href = 'news-company.html';
      setBilingualText(nextLabel, '公司动态', 'Company News');
    } else if (pageType === 'index') {
      setBilingualText(levels[1], '内容索引', 'Publication index');
      if (next) next.href = 'news.html';
      setBilingualText(nextLabel, '返回新闻与洞察', 'Return to newsroom');
    } else if (pageType === 'document') {
      setBilingualText(levels[1], 'PDF 阅读', 'PDF reader');
      if (next) next.href = 'news.html';
      setBilingualText(nextLabel, '返回新闻与洞察', 'Return to newsroom');
    } else if (pageType === 'article') {
      setBilingualText(levels[1], '文章阅读', 'Article');
      if (next) next.href = 'news.html';
      setBilingualText(nextLabel, '返回新闻与洞察', 'Return to newsroom');
    }
  }

  function applyMetadataLanguage(language) {
    const lang = language === 'en' ? 'en' : 'zh';
    const titleElement = document.querySelector('title[data-v750-meta-title]');
    if (titleElement) document.title = titleElement.dataset[lang === 'en' ? 'en' : 'cn'] || titleElement.textContent;
    document.querySelectorAll('meta[data-v750-meta][data-cn][data-en]').forEach((element) => {
      element.setAttribute('content', element.dataset[lang === 'en' ? 'en' : 'cn'] || '');
    });
    const locale = document.querySelector('meta[data-v750-locale]');
    if (locale) locale.setAttribute('content', lang === 'en' ? 'en_US' : 'zh_CN');
  }

  function syncArticleToc(language) {
    if (pageType !== 'article') return;
    const toc = document.querySelector('.v430-article-toc');
    if (!toc) return;
    const lang = language === 'en' ? 'en' : 'zh';
    const container = lang === 'en'
      ? document.querySelector('.v750-article-en__content')
      : document.querySelector('[data-v750-original-cn] .news-content');
    const headings = container ? [...container.querySelectorAll('h2, h3')] : [];
    toc.setAttribute('data-v720-language-managed', 'true');
    toc.setAttribute('aria-label', lang === 'en' ? 'Article index' : '文章目录');
    toc.hidden = headings.length === 0;
    if (!headings.length) return;

    let title = toc.querySelector('strong');
    if (!title) {
      title = document.createElement('strong');
      toc.prepend(title);
    }
    title.textContent = lang === 'en' ? 'ARTICLE INDEX' : '文章目录';
    let list = toc.querySelector('ol');
    if (!list) {
      list = document.createElement('ol');
      toc.append(list);
    }
    list.replaceChildren();
    headings.forEach((heading, index) => {
      const id = `${lang}-article-section-${String(index + 1).padStart(2, '0')}`;
      heading.id = id;
      const item = document.createElement('li');
      const link = document.createElement('a');
      link.href = `#${id}`;
      link.textContent = heading.textContent.trim();
      item.append(link);
      list.append(item);
    });
  }

  function applyLanguage(language = storedLanguage()) {
    const lang = language === 'en' ? 'en' : 'zh';
    document.documentElement.dataset.lang = lang;
    document.documentElement.lang = lang === 'en' ? 'en' : 'zh-CN';
    document.body?.classList.toggle('is-news-en', lang === 'en');

    document.querySelectorAll('[data-news-cn][data-news-en]').forEach((element) => {
      element.textContent = languageValue(element, lang);
    });
    document.querySelectorAll('[data-news-date-cn][data-news-date-en]').forEach((element) => {
      element.textContent = languageValue(element, lang, 'newsDate');
    });
    document.querySelectorAll('[data-alt-cn][data-alt-en]').forEach((element) => {
      element.setAttribute('alt', languageValue(element, lang, 'alt'));
    });
    document.querySelectorAll('[data-aria-cn][data-aria-en]').forEach((element) => {
      element.setAttribute('aria-label', languageValue(element, lang, 'aria'));
    });

    applyMetadataLanguage(lang);
    window.clearTimeout(metadataLanguageTimer);
    metadataLanguageTimer = window.setTimeout(() => applyMetadataLanguage(lang), 140);

    const original = document.querySelector('[data-v750-original-cn]');
    const english = document.querySelector('[data-v750-article-en]');
    if (original && english) {
      original.hidden = lang === 'en';
      english.hidden = lang !== 'en';
    }
    syncArticleToc(lang);

    if (indexState) updateIndex(indexState, false);
  }

  function initReveals() {
    const items = [...document.querySelectorAll('[data-v750-reveal]')];
    if (!items.length) return;
    document.documentElement.classList.add('v750-enhanced');
    const reduced = window.matchMedia('(prefers-reduced-motion: reduce)').matches;
    if (reduced || !('IntersectionObserver' in window)) {
      items.forEach((item) => item.classList.add('is-visible'));
      return;
    }
    const observer = new IntersectionObserver((entries) => {
      entries.forEach((entry) => {
        if (!entry.isIntersecting) return;
        entry.target.classList.add('is-visible');
        observer.unobserve(entry.target);
      });
    }, { rootMargin: '0px 0px -8% 0px', threshold: 0.08 });
    items.forEach((item) => observer.observe(item));
  }

  function initIndex() {
    const items = [...document.querySelectorAll('[data-index-item]')];
    if (!items.length) return;
    const categoryButtons = [...document.querySelectorAll('[data-index-category]')];
    const yearSelect = document.querySelector('[data-index-year]');
    const moreButton = document.querySelector('[data-index-more]');
    const empty = document.querySelector('[data-index-empty]');
    const status = document.querySelector('[data-index-status]');
    const requestedCategory = new URLSearchParams(location.search).get('category');
    const validCategory = categoryButtons.some((button) => button.dataset.indexCategory === requestedCategory);
    indexState = {
      items,
      categoryButtons,
      yearSelect,
      moreButton,
      empty,
      status,
      category: validCategory ? requestedCategory : 'all',
      year: 'all',
      limit: 12,
      step: 12,
    };

    categoryButtons.forEach((button) => {
      button.addEventListener('click', () => {
        indexState.category = button.dataset.indexCategory || 'all';
        indexState.limit = indexState.step;
        updateIndex(indexState, true);
      });
    });
    yearSelect?.addEventListener('change', () => {
      indexState.year = yearSelect.value || 'all';
      indexState.limit = indexState.step;
      updateIndex(indexState, true);
    });
    moreButton?.addEventListener('click', () => {
      indexState.limit += indexState.step;
      updateIndex(indexState, false);
    });
    updateIndex(indexState, false);
  }

  function updateIndex(state, updateUrl) {
    const matching = state.items.filter((item) => {
      const categoryMatch = state.category === 'all' || item.dataset.category === state.category;
      const yearMatch = state.year === 'all' || item.dataset.year === state.year;
      return categoryMatch && yearMatch;
    });
    state.items.forEach((item) => {
      const position = matching.indexOf(item);
      item.hidden = position === -1 || position >= state.limit;
    });
    state.categoryButtons.forEach((button) => {
      const selected = button.dataset.indexCategory === state.category;
      button.classList.toggle('is-active', selected);
      button.setAttribute('aria-pressed', String(selected));
    });
    if (state.yearSelect && state.yearSelect.value !== state.year) state.yearSelect.value = state.year;
    if (state.empty) state.empty.hidden = matching.length > 0;
    if (state.moreButton) state.moreButton.hidden = matching.length <= state.limit;
    if (state.status) {
      const shown = Math.min(matching.length, state.limit);
      const isEnglish = document.documentElement.dataset.lang === 'en';
      state.status.textContent = isEnglish
        ? `Showing ${shown} of ${matching.length} publications`
        : `显示 ${shown} / ${matching.length} 篇`;
    }
    if (updateUrl && history.replaceState) {
      const url = new URL(location.href);
      if (state.category === 'all') url.searchParams.delete('category');
      else url.searchParams.set('category', state.category);
      history.replaceState({}, '', `${url.pathname}${url.search}${location.hash || '#content-index'}`);
    }
  }

  function initDocumentReader() {
    const frame = document.querySelector('[data-document-frame]');
    if (!frame) return;
    const catalog = observerCatalog();
    const params = new URLSearchParams(location.search);
    const slug = params.get('doc') || '';
    const from = params.get('from') || slug;
    const item = catalog.find((entry) => entry.slug === slug);
    const error = document.querySelector('[data-document-error]');
    if (!item || !/^news-[a-z0-9-]+$/i.test(slug)) {
      frame.hidden = true;
      if (error) error.hidden = false;
      return;
    }

    const articleLink = document.querySelector('[data-document-article-link]');
    const categoryLink = document.querySelector('[data-document-category-link]');
    const back = document.querySelector('[data-document-back]');
    const open = document.querySelector('[data-document-open]');
    const download = document.querySelector('[data-document-download]');
    const title = document.querySelector('[data-document-title]');
    const toolbarTitle = document.querySelector('[data-document-toolbar-title]');
    const category = document.querySelector('[data-document-category]');
    const meta = document.querySelector('[data-document-meta]');
    const returnFile = catalog.some((entry) => entry.slug === from) ? `${from}.html` : item.file;

    frame.setAttribute('data', item.pdf);
    frame.dataset.ariaCn = `${item.title} PDF`;
    frame.dataset.ariaEn = `${item.titleEn || 'Article'} PDF`;
    frame.setAttribute('aria-label', frame.dataset.ariaCn);
    if (articleLink) articleLink.href = returnFile;
    if (categoryLink) {
      categoryLink.href = item.observerCategory === 'industry' ? 'news-insights.html' : 'news-company.html';
      categoryLink.dataset.newsCn = item.observerCategoryCn || '公司动态';
      categoryLink.dataset.newsEn = item.observerCategoryEn || 'Company News';
    }
    if (back) back.href = returnFile;
    if (open) open.href = item.pdf;
    if (download) {
      download.href = item.pdf;
      download.setAttribute('download', `${item.slug}-article-record.pdf`);
    }
    if (title) {
      title.dataset.newsCn = item.title;
      title.dataset.newsEn = item.titleEn || item.title;
    }
    if (toolbarTitle) {
      toolbarTitle.dataset.newsCn = item.title;
      toolbarTitle.dataset.newsEn = item.titleEn || item.title;
    }
    if (category) {
      category.dataset.newsCn = item.observerCategoryCn || '公司动态';
      category.dataset.newsEn = item.observerCategoryEn || 'Company News';
    }
    if (meta) {
      meta.dataset.newsCn = `${item.dateCn} / ${item.brand} / 文章同名归档 PDF`;
      meta.dataset.newsEn = `${item.dateEn} / ${item.brand} / same-name archival article PDF`;
    }
  }

  function initExternalLinkSafety() {
    document.querySelectorAll('a[target="_blank"]').forEach((link) => {
      const rel = new Set((link.getAttribute('rel') || '').split(/\s+/).filter(Boolean));
      rel.add('noopener');
      rel.add('noreferrer');
      link.setAttribute('rel', [...rel].join(' '));
    });
  }

  function routeLegacyCategoryLink() {
    if (pageType !== 'newsroom') return false;
    const params = new URLSearchParams(location.search);
    const category = params.get('category') || '';
    const allowed = new Set(['technology-product', 'application-engineering', 'industry-collaboration', 'enterprise-brand']);
    if (!allowed.has(category)) return false;
    const destination = category === 'industry-collaboration' || category === 'enterprise-brand'
      ? 'news-company.html'
      : 'news-insights.html';
    location.replace(destination);
    return true;
  }

  function init() {
    if (routeLegacyCategoryLink()) return;
    initDocumentReader();
    initIndex();
    initExternalLinkSafety();
    initSharedNavigationAccessibility();
    initContextNavigation();
    applyLanguage(storedLanguage());
    initReveals();
    document.documentElement.dataset.v750Ready = 'true';
  }

  document.addEventListener('dbc:languagechange', (event) => {
    applyLanguage(event.detail?.language === 'en' ? 'en' : 'zh');
  });
  document.addEventListener('dbc:translations-loaded', () => applyLanguage(storedLanguage()));
  if (document.readyState === 'loading') document.addEventListener('DOMContentLoaded', init, { once: true });
  else init();
})();