/* =========================================================================
   docs.js — tabbed code blocks + copy buttons + scrollspy TOC
   Vanilla. Each [data-code-tabs] group: buttons swap panels. Each code panel
   gets a hover copy button. TOC links get aria-current as you scroll.
   ========================================================================= */

(function () {
  'use strict';

  /* ---- tabbed code blocks ---- */
  function initTabs() {
    document.querySelectorAll('[data-code-tabs]').forEach((group) => {
      const buttons = group.querySelectorAll('.code-tabs button');
      const panels = group.querySelectorAll('.code-panel');
      buttons.forEach((btn) => {
        btn.addEventListener('click', () => {
          const target = btn.dataset.tab;
          buttons.forEach((b) => b.setAttribute('aria-selected', String(b === btn)));
          panels.forEach((p) => p.setAttribute('data-active', String(p.dataset.tab === target)));
        });
      });
    });
  }

  /* ---- copy buttons on code panels ---- */
  function initCopy() {
    document.querySelectorAll('.code-panel').forEach((panel) => {
      const wrap = panel.closest('.code-wrap');
      if (!wrap || wrap.querySelector('.code-copy')) return;
      const btn = document.createElement('button');
      btn.className = 'code-copy';
      btn.type = 'button';
      btn.textContent = 'Copy';
      btn.setAttribute('aria-label', 'Copy code');
      btn.addEventListener('click', async () => {
        try {
          await navigator.clipboard.writeText(panel.innerText);
        } catch (e) {
          const ta = document.createElement('textarea');
          ta.value = panel.innerText;
          document.body.appendChild(ta); ta.select();
          document.execCommand('copy'); document.body.removeChild(ta);
        }
        btn.textContent = 'Copied';
        setTimeout(() => (btn.textContent = 'Copy'), 1500);
      });
      wrap.appendChild(btn);
    });
  }

  /* ---- scrollspy: highlight the TOC link for the section in view ---- */
  function initScrollspy() {
    const links = Array.from(document.querySelectorAll('.doc-toc a'));
    if (!links.length || !('IntersectionObserver' in window)) return;
    const map = new Map();
    const headings = [];
    links.forEach((link) => {
      const id = link.getAttribute('href');
      if (!id || !id.startsWith('#')) return;
      const el = document.querySelector(id);
      if (el) { map.set(el, link); headings.push(el); }
    });
    const io = new IntersectionObserver(
      (entries) => {
        entries.forEach((entry) => {
          const link = map.get(entry.target);
          if (!link) return;
          if (entry.isIntersecting) {
            links.forEach((l) => l.removeAttribute('aria-current'));
            link.setAttribute('aria-current', 'true');
          }
        });
      },
      { rootMargin: '-30% 0px -60% 0px' }
    );
    headings.forEach((h) => io.observe(h));
  }

  function boot() { initTabs(); initCopy(); initScrollspy(); }
  if (document.readyState === 'loading') {
    document.addEventListener('DOMContentLoaded', boot);
  } else { boot(); }
})();