(function () {
  'use strict';

  if (window.__BIOTEN_PACKAGING_FAMILY_V7140__) return;
  window.__BIOTEN_PACKAGING_FAMILY_V7140__ = true;

  const root = document.documentElement;
  const body = document.body;
  const languageKey = 'dbc-site-language';
  const pageIsEnglishReady = root.dataset.enReady === 'true'
    || (body && body.dataset.enReady === 'true');

  function getLanguage() {
    try {
      const query = new URLSearchParams(window.location.search).get('lang');
      const preference = query === 'zh' || query === 'en'
        ? query
        : (root.dataset.languagePreference === 'en'
          || root.dataset.lang === 'en'
          || localStorage.getItem(languageKey) === 'en' ? 'en' : 'zh');
      return pageIsEnglishReady ? preference : 'zh';
    } catch (error) {
      return pageIsEnglishReady && root.dataset.lang === 'en' ? 'en' : 'zh';
    }
  }

  function setText(element, language) {
    const htmlKey = language === 'en' ? 'htmlEn' : 'htmlZh';
    const textKey = language === 'en' ? 'en' : 'zh';
    if (element.dataset[htmlKey] !== undefined) {
      element.innerHTML = element.dataset[htmlKey];
    } else if (element.dataset[textKey] !== undefined) {
      element.textContent = element.dataset[textKey];
    }
  }

  function applyLanguage(language) {
    const next = language === 'en' ? 'en' : 'zh';
    // Do not rewrite the observed attribute when the value is unchanged.
    // MutationObserver fires for attribute writes, so an unconditional write
    // here can create a self-sustaining microtask loop and freeze the page.
    if (root.dataset.lang !== next) root.dataset.lang = next;
    root.lang = next === 'en' ? 'en' : 'zh-CN';
    // A Chinese-authoritative page may render a Chinese fallback while the
    // visitor's global English preference remains intact for the next fully
    // bilingual route. Never persist the fallback as a new preference.
    if (pageIsEnglishReady) {
      try { localStorage.setItem(languageKey, next); } catch (error) { /* no-op */ }
    }

    document.querySelectorAll('[data-zh], [data-html-zh]').forEach(function (element) {
      setText(element, next);
    });

    document.querySelectorAll('[data-alt-zh]').forEach(function (element) {
      element.alt = next === 'en' ? (element.dataset.altEn || '') : (element.dataset.altZh || '');
    });

    document.querySelectorAll('[data-label-zh]').forEach(function (element) {
      element.setAttribute('aria-label', next === 'en' ? (element.dataset.labelEn || '') : (element.dataset.labelZh || ''));
    });

    if (body) {
      const title = next === 'en' ? body.dataset.pageTitleEn : body.dataset.pageTitleZh;
      const description = next === 'en' ? body.dataset.pageDescriptionEn : body.dataset.pageDescriptionZh;
      if (title) document.title = title;
      const descriptionTag = document.querySelector('meta[name="description"]');
      if (descriptionTag && description) descriptionTag.content = description;
    }

    updateResultCount(next);
  }

  function updateResultCount(language) {
    const cards = Array.from(document.querySelectorAll('[data-bp7140-release-card]')).filter(function (card) {
      return !card.hidden;
    });
    const target = document.querySelector('[data-bp7140-result-count]');
    if (!target) return;
    target.textContent = language === 'en'
      ? cards.length + (cards.length === 1 ? ' release' : ' releases')
      : cards.length + ' 篇发布';
  }

  function initFilters() {
    const filters = Array.from(document.querySelectorAll('[data-bp7140-filter]'));
    const cards = Array.from(document.querySelectorAll('[data-bp7140-release-card]'));
    if (!filters.length || !cards.length) return;

    filters.forEach(function (button) {
      button.addEventListener('click', function () {
        const value = button.dataset.bp7140Filter || 'all';
        filters.forEach(function (item) {
          item.setAttribute('aria-pressed', String(item === button));
        });
        cards.forEach(function (card) {
          card.hidden = value !== 'all' && card.dataset.bp7140Category !== value;
        });
        updateResultCount(getLanguage());
      });
    });
  }

  function initReveal() {
    const targets = Array.from(document.querySelectorAll('[data-bp7140-reveal]'));
    if (!targets.length) return;
    // Progressive enhancement: content is visible by default in CSS and is
    // hidden for animation only after this initializer is known to be alive.
    root.classList.add('bp7140-motion-ready');
    if (!('IntersectionObserver' in window) || window.matchMedia('(prefers-reduced-motion: reduce)').matches) {
      targets.forEach(function (target) { target.classList.add('is-visible'); });
      return;
    }
    const observer = new IntersectionObserver(function (entries) {
      entries.forEach(function (entry) {
        if (!entry.isIntersecting) return;
        entry.target.classList.add('is-visible');
        observer.unobserve(entry.target);
      });
    }, { rootMargin: '0px 0px -8% 0px', threshold: .08 });
    targets.forEach(function (target) { observer.observe(target); });
    // Final safety net: an observer implementation must never be able to leave
    // readable content transparent indefinitely.
    window.setTimeout(function () {
      targets.forEach(function (target) { target.classList.add('is-visible'); });
    }, 2400);
  }

  function initToc() {
    const links = Array.from(document.querySelectorAll('.bp7140-toc a[href^="#"]'));
    if (!links.length || !('IntersectionObserver' in window)) return;
    const pairs = links.map(function (link) {
      return { link: link, section: document.querySelector(link.getAttribute('href')) };
    }).filter(function (pair) { return Boolean(pair.section); });
    if (!pairs.length) return;

    const observer = new IntersectionObserver(function (entries) {
      const visible = entries.filter(function (entry) { return entry.isIntersecting; })
        .sort(function (a, b) { return a.boundingClientRect.top - b.boundingClientRect.top; });
      if (!visible.length) return;
      const id = visible[0].target.id;
      pairs.forEach(function (pair) {
        if (pair.section.id === id) pair.link.setAttribute('aria-current', 'true');
        else pair.link.removeAttribute('aria-current');
      });
    }, { rootMargin: '-22% 0px -62% 0px', threshold: 0 });
    pairs.forEach(function (pair) { observer.observe(pair.section); });
  }

  function initContextNavigation() {
    const navigation = document.querySelector('[data-bp7160-context-route]');
    if (!navigation) return;
    const links = Array.from(navigation.querySelectorAll('a'));
    const overview = links.find(function (link) { return !link.hash; });
    const sections = links.map(function (link) {
      if (!link.hash) return null;
      const section = document.querySelector(link.hash);
      return section ? { link: link, section: section } : null;
    }).filter(Boolean);
    if (!overview || !sections.length) return;

    let scheduled = false;
    function setCurrent(link) {
      links.forEach(function (item) { item.removeAttribute('aria-current'); });
      link.setAttribute('aria-current', link === overview ? 'page' : 'location');
    }
    function updateCurrent() {
      scheduled = false;
      const navigationRect = navigation.getBoundingClientRect();
      if (navigationRect.top >= window.innerHeight) {
        setCurrent(overview);
        return;
      }
      const navigationBottom = Math.min(navigationRect.bottom, 132);
      const threshold = navigationBottom + Math.min(110, window.innerHeight * .14);
      let current = overview;
      sections.forEach(function (pair) {
        if (pair.section.getBoundingClientRect().top <= threshold) current = pair.link;
      });
      setCurrent(current);
    }
    function scheduleUpdate() {
      if (scheduled) return;
      scheduled = true;
      window.requestAnimationFrame(updateCurrent);
    }

    links.forEach(function (link) {
      link.addEventListener('click', function () {
        window.setTimeout(scheduleUpdate, 80);
      });
    });
    window.addEventListener('scroll', scheduleUpdate, { passive: true });
    window.addEventListener('resize', scheduleUpdate);
    window.addEventListener('hashchange', scheduleUpdate);
    scheduleUpdate();
  }

  function initParticles() {
    const field = document.querySelector('[data-bp7140-material-field]');
    if (!field || window.matchMedia('(prefers-reduced-motion: reduce)').matches) return;
    const count = window.innerWidth < 680 ? 18 : 34;
    for (let index = 0; index < count; index += 1) {
      const particle = document.createElement('span');
      particle.className = 'bp7140-particle';
      particle.style.setProperty('--top', (9 + Math.random() * 72).toFixed(2) + '%');
      particle.style.setProperty('--right', (4 + Math.random() * 42).toFixed(2) + '%');
      particle.style.setProperty('--size', (2 + Math.random() * 6).toFixed(2) + 'px');
      particle.style.setProperty('--duration', (4.8 + Math.random() * 5.4).toFixed(2) + 's');
      particle.style.setProperty('--delay', (-Math.random() * 6).toFixed(2) + 's');
      particle.style.setProperty('--dx', (-30 + Math.random() * 60).toFixed(2) + 'px');
      particle.style.setProperty('--dy', (-48 + Math.random() * 96).toFixed(2) + 'px');
      field.appendChild(particle);
    }
    const line = document.createElement('span');
    line.className = 'bp7140-film-line';
    field.appendChild(line);
  }

  function initIntakeContext() {
    if (!body.classList.contains('bp7140-intake-page')) return;
    const params = new URLSearchParams(window.location.search);
    const keys = ['domain', 'topic', 'route', 'source'];
    const values = {};
    const labels = {
      'packaging': { zh: '博碳包装项目', en: 'BIOTEN Packaging project' },
      'food-beverage': { zh: '食品与饮料包装', en: 'Food & beverage packaging' },
      'beauty-care': { zh: '美妆与个护包装', en: 'Beauty & personal care packaging' },
      'medical-outer': { zh: '医药与医疗外包装', en: 'Pharma & medical outer packaging' },
      'special-performance': { zh: '特种包装', en: 'Specialty packaging' },
      'pha-barrier-emulsion': { zh: '博碳阻隔乳液', en: 'BIOTEN barrier emulsion' },
      'waterborne-coated-paper': { zh: '博碳水涂纸', en: 'BIOTEN waterborne-coated paper' },
      'bioten-foodserviceware': { zh: '博碳餐饮具', en: 'BIOTEN foodserviceware' },
      'paper-cup-sample': { zh: '纸杯', en: 'Paper cups' },
      'paper-box-sample': { zh: '纸盒', en: 'Paper cartons' },
      'paper-bag-sample': { zh: '纸袋等制品', en: 'Paper bags and related articles' },
      'other-sample': { zh: '其他纸基包装样品', en: 'Other fiber-based packaging samples' },
      'packaging-home-sample': { zh: '首页样品申请', en: 'Homepage sample request' },
      'coating-converting-partnership': { zh: '涂布与加工成型合作', en: 'Coating and converting partnership' },
      'packaging-product-release': { zh: '新应用发布与合作申请', en: 'New application release and partnership application' }
    };
    const requestedSampleLabels = {
      'pha-barrier-emulsion': '博碳阻隔乳液 / BIOTEN barrier emulsion',
      'waterborne-coated-paper': '博碳水涂纸 / BIOTEN waterborne-coated paper',
      'bioten-foodserviceware': '博碳餐饮具 / BIOTEN foodserviceware',
      'paper-cup-sample': '纸杯 / Paper cups',
      'paper-box-sample': '纸盒 / Paper cartons',
      'paper-bag-sample': '纸袋等制品 / Paper bags and related articles',
      'other-sample': '其他纸基包装样品 / Other fiber-based packaging samples'
    };
    keys.forEach(function (key) { values[key] = params.get(key) || ''; });
    const sourceInput = document.querySelector('input[name="source"]');
    if (sourceInput) sourceInput.value = values.source || 'packaging-direct';
    keys.forEach(function (key) {
      let input = document.querySelector('input[name="' + key + '"]');
      if (!input && values[key]) {
        input = document.createElement('input');
        input.type = 'hidden';
        input.name = key;
        const form = document.querySelector('form');
        if (form) form.appendChild(input);
      }
      if (input && values[key]) input.value = values[key];
    });
    const context = document.querySelector('[data-bp7140-intake-context]');
    if (context && (values.domain || values.topic || values.route || values.source)) {
      context.hidden = false;
      const rawValues = [values.domain, values.topic, values.route, values.source].filter(Boolean);
      const summaryZh = rawValues.map(function (value) { return labels[value] ? labels[value].zh : value; }).join(' · ');
      const summaryEn = rawValues.map(function (value) { return labels[value] ? labels[value].en : value; }).join(' · ');
      const output = context.querySelector('[data-bp7140-context-value]');
      if (output) {
        output.dataset.zh = summaryZh;
        output.dataset.en = summaryEn;
        output.textContent = getLanguage() === 'en' ? summaryEn : summaryZh;
      }
    }
    if (values.source === 'packaging-home-sample') {
      const sampleNeed = document.querySelector('input[name="request_need"][value="样品/纸样测试"]');
      if (sampleNeed) sampleNeed.checked = true;
      const sampleSelection = document.querySelector('input[name="sample_selection"]');
      if (sampleSelection && requestedSampleLabels[values.topic] && !sampleSelection.value) {
        sampleSelection.value = requestedSampleLabels[values.topic];
      }
    }
    if (values.topic === 'coating-converting-partnership' || values.source === 'packaging-product-release') {
      const partnershipNeed = document.querySelector('input[name="request_need"][value="商务合作/报价咨询"]');
      if (partnershipNeed) partnershipNeed.checked = true;
      const application = document.querySelector('input[name="application"]');
      if (application && !application.value) {
        application.value = '涂布、印刷、模切、制盒或加工成型合作 / Coating, printing, die cutting, carton making or converting partnership';
      }
      const message = document.querySelector('textarea[name="message"]');
      if (message && !message.value) {
        message.value = '希望围绕博碳新应用开展打样、加工服务或市场协同 / I would like to discuss prototyping, converting services or market collaboration for a BIOTEN application';
      }
    }
  }

  document.addEventListener('dbc:languagechange', function (event) {
    applyLanguage(event.detail && event.detail.language === 'en' ? 'en' : 'zh');
  });

  const languageObserver = new MutationObserver(function () {
    applyLanguage(root.dataset.lang === 'en' ? 'en' : 'zh');
  });
  languageObserver.observe(root, { attributes: true, attributeFilter: ['data-lang'] });

  initFilters();
  initReveal();
  initToc();
  initContextNavigation();
  initParticles();
  initIntakeContext();
  applyLanguage(getLanguage());
}());