/* Progressive enhancement: without JS, the tab links jump to visible sections.
   Add a link and matching panel to extend the tabs (for example, a future SAE tab). */
(function () {
  const list = document.querySelector('.landing-tabs');
  if (!list) return;
  const tabs = Array.from(list.querySelectorAll('a[href^="#"]'));
  const panels = tabs.map(tab => document.getElementById(tab.hash.slice(1)));
  if (panels.some(panel => !panel)) return;

  list.setAttribute('role', 'tablist');
  tabs.forEach((tab, index) => {
    tab.setAttribute('role', 'tab');
    tab.setAttribute('aria-controls', panels[index].id);
    panels[index].setAttribute('role', 'tabpanel');
    panels[index].tabIndex = 0;
  });

  const activate = (index, focus = false) => {
    tabs.forEach((tab, i) => {
      const selected = i === index;
      tab.setAttribute('aria-selected', String(selected));
      tab.tabIndex = selected ? 0 : -1;
      panels[i].hidden = !selected;
    });
    if (focus) tabs[index].focus();
  };

  const fromHash = () => {
    const target = document.getElementById(location.hash.slice(1));
    // Keep the original overview's quick-start and download links useful.
    const aliases = { start: 'use', availability: 'models', cite: 'models', more: 'models', zeroshot: 'overview', scaling: 'overview', finetune: 'overview' };
    const alias = aliases[location.hash.slice(1)];
    const index = panels.findIndex(panel => panel.id === alias || panel === target || (target && panel.contains(target)));
    activate(index < 0 ? 0 : index);
  };

  tabs.forEach((tab, index) => {
    tab.addEventListener('click', event => {
      if (event.metaKey || event.ctrlKey || event.shiftKey || event.altKey || event.button !== 0) return;
      event.preventDefault();
      activate(index);
      // Preserve Hugging Face's query parameters when updating the fragment.
      if (location.hash !== tab.hash) history.pushState(null, '', tab.hash);
    });
    tab.addEventListener('keydown', event => {
      let next;
      if (event.key === 'ArrowRight') next = (index + 1) % tabs.length;
      if (event.key === 'ArrowLeft') next = (index + tabs.length - 1) % tabs.length;
      if (event.key === 'Home') next = 0;
      if (event.key === 'End') next = tabs.length - 1;
      if (event.key === ' ' || event.key === 'Enter') next = index;
      if (next === undefined) return;
      event.preventDefault();
      activate(next, true);
      history.replaceState(null, '', tabs[next].hash);
    });
  });
  window.addEventListener('hashchange', fromHash);
  window.addEventListener('popstate', fromHash);
  fromHash();
})();

/* Copy-to-clipboard for the BibTeX blocks. The entry stays selectable without JS. */
(function () {
  const fallback = text => {
    const area = document.createElement('textarea');
    area.value = text;
    area.setAttribute('readonly', '');
    area.style.position = 'fixed';
    area.style.opacity = '0';
    document.body.appendChild(area);
    area.select();
    let ok = false;
    try { ok = document.execCommand('copy'); } catch (e) { ok = false; }
    area.remove();
    return ok;
  };
  document.querySelectorAll('.copy-bibtex').forEach(button => {
    const label = button.textContent;
    const code = button.parentElement.querySelector('pre code');
    if (!code) return;
    let timer = null;
    const done = (state, text) => {
      button.dataset.state = state;
      button.textContent = text;
      clearTimeout(timer);
      timer = setTimeout(() => { delete button.dataset.state; button.textContent = label; }, 1800);
    };
    button.addEventListener('click', () => {
      const text = code.textContent;
      const write = navigator.clipboard && window.isSecureContext
        ? navigator.clipboard.writeText(text).then(() => true, () => fallback(text))
        : Promise.resolve(fallback(text));
      write.then(ok => done(ok ? 'copied' : 'failed', ok ? 'Copied' : 'Select and copy'));
    });
  });
})();