// ═══════════════════════════════════════════════════════
// QR Code (using qrcode-generator library)
// ═══════════════════════════════════════════════════════
function generateQR() {
  const data = document.getElementById('qrInput').value.trim();
  const container = document.getElementById('qrCanvas');
  const ph = document.getElementById('qrPlaceholder');
  if (!data) { container.style.display = 'none'; ph.style.display = ''; return; }
  if (typeof qrcode === 'undefined') { ph.textContent = 'Loading QR library...'; return; }

  try {
    const qr = qrcode(0, 'M');
    qr.addData(data);
    qr.make();
    container.innerHTML = qr.createSvgTag({ cellSize: 4, margin: 8, scalable: true });
    // Style the SVG
    const svg = container.querySelector('svg');
    if (svg) {
      svg.style.width = '256px';
      svg.style.height = '256px';
      svg.style.background = '#fff';
      svg.style.borderRadius = '12px';
    }
    container.style.display = '';
    ph.style.display = 'none';
  } catch (err) {
    ph.textContent = err.message;
    container.style.display = 'none';
    ph.style.display = '';
  }
}

function downloadQR() {
  const container = document.getElementById('qrCanvas');
  if (container.style.display === 'none') return;
  const svg = container.querySelector('svg');
  if (!svg) return;

  // Convert SVG to PNG via canvas
  const svgData = new XMLSerializer().serializeToString(svg);
  const img = new Image();
  img.onload = function () {
    const canvas = document.createElement('canvas');
    canvas.width = 512;
    canvas.height = 512;
    const ctx = canvas.getContext('2d');
    ctx.fillStyle = '#ffffff';
    ctx.fillRect(0, 0, 512, 512);
    ctx.drawImage(img, 0, 0, 512, 512);
    const a = document.createElement('a');
    a.href = canvas.toDataURL('image/png');
    a.download = 'qrcode.png';
    a.click();
  };
  img.src = 'data:image/svg+xml;base64,' + btoa(unescape(encodeURIComponent(svgData)));
}