// Minimal CSS syntax highlighter for the docs (shared).
// It converts plain-text CSS inside `.css-view` into highlighted HTML using
// the existing demo.css token classes: .kwd .str .num .punc .com .attr .val .fun

(function () {
  function escapeHtml(s) {
    return String(s)
      .replace(/&/g, '&')
      .replace(/</g, '&lt;')
      .replace(/>/g, '&gt;');
  }

  function highlightCSS(input) {
    let s = escapeHtml(input);

    // Comments
    s = s.replace(/\/\*[\s\S]*?\*\//g, (m) => `<span class="com">${m}</span>`);

    // Strings
    s = s.replace(/("(?:\\.|[^"\\])*"|'(?:\\.|[^'\\])*')/g, (m) => `<span class="str">${m}</span>`);

    // @rules
    s = s.replace(/(^|\s)(@[\w-]+)/g, (m, p1, p2) => `${p1}<span class="kwd">${p2}</span>`);

    // Hex colors
    s = s.replace(/(#(?:[0-9a-fA-F]{3}|[0-9a-fA-F]{6}|[0-9a-fA-F]{8}))/g, (m) => `<span class="num">${m}</span>`);

    // Numbers with units (very rough, but good enough visually)
    s = s.replace(/(\b\d+(?:\.\d+)?)(%|px|rem|em|vh|vw|vmin|vmax|deg|turn|s|ms)?\b/g, (m, n, unit) => {
      return `<span class="num">${n}</span>${unit || ''}`;
    });

    // Property names: "prop: value"
    s = s.replace(/(^|\n)(\s*)([a-zA-Z_-][\w-]*)(\s*):/g, (m, p1, ws, prop, ws2) => {
      return `${p1}${ws}<span class="attr">${prop}</span>${ws2}<span class="punc">:</span>`;
    });

    // Highlight braces / punctuation
    s = s.replace(/([{}();,])/g, (m) => `<span class="punc">${m}</span>`);

    // Selectors (line before "{"), skip @rules
    s = s.replace(/(^|\n)([^\n{]+?)(\s*)(<span class="punc">\{<\/span>)/g, (m, p1, sel, ws, brace) => {
      const trimmed = sel.trimStart();
      if (trimmed.startsWith('@')) return `${p1}${sel}${ws}${brace}`;
      return `${p1}<span class="fun">${sel}</span>${ws}${brace}`;
    });

    // Values: after ":" until ";" or "}" (best-effort, runs after punctuation)
    s = s.replace(/(<span class="punc">:<\/span>)([^;\n}]+)(?=(<span class="punc">;|<span class="punc">\}))/g, (m, colon, val) => {
      // avoid re-highlighting spans
      if (val.includes('<span')) return `${colon}${val}`;
      return `${colon}<span class="val">${val}</span>`;
    });

    return s;
  }

  function enhance() {
    const blocks = document.querySelectorAll('.css-view');
    blocks.forEach((el) => {
      try {
        if (el.dataset.highlighted === '1') return;
        const text = el.textContent || '';
        // If already contains spans, assume it's already highlighted.
        if (el.innerHTML.includes('<span')) {
          el.dataset.highlighted = '1';
          return;
        }
        el.innerHTML = highlightCSS(text);
        el.dataset.highlighted = '1';
      } catch (_) {
        // Never break the page; just skip highlighting if anything goes wrong.
      }
    });
  }

  // Expose for pages that want to re-run manually
  window.__highlightCssViews = enhance;

  if (document.readyState === 'loading') {
    document.addEventListener('DOMContentLoaded', enhance, { once: true });
  } else {
    enhance();
  }

  // Re-run when switching to the CSS tab (covers cases where the page
  // injects/replaces code blocks after load or during navigation).
  document.addEventListener(
    'click',
    (e) => {
      const tab = e.target && e.target.closest ? e.target.closest('.tab') : null;
      if (!tab) return;
      const label = (tab.textContent || '').trim().toLowerCase();
      if (label === 'css') {
        // Defer so the tab switch can toggle DOM/classes first
        setTimeout(enhance, 0);
      }
    },
    true
  );

  // Observe DOM changes to catch dynamically added `.css-view` blocks.
  try {
    const mo = new MutationObserver(() => {
      // Cheap debounce via microtask
      Promise.resolve().then(enhance);
    });
    mo.observe(document.documentElement, {
      subtree: true,
      childList: true,
      characterData: true
    });
  } catch (_) {}
})();