/** Strip whitespace and download a remote desktop capture as a JPEG file. */
export function sanitizeScreenshotBase64(raw: string): string {
  const trimmed = raw.trim().replace(/^\uFEFF/, '');
  let best = '';
  for (const part of trimmed.split(/\s+/)) {
    const cleaned = part.replace(/[^A-Za-z0-9+/=]/g, '');
    if (cleaned.length > best.length && cleaned.length >= 100) {
      best = cleaned;
    }
  }
  if (best.length >= 100) return best;
  const fallback = trimmed.replace(/[^A-Za-z0-9+/=]/g, '');
  return fallback.length >= 100 ? fallback : '';
}

export type CaptureDownloadKind = 'screenshot' | 'camera';

export function downloadScreenshotFromBase64(
  base64: string,
  agentLabel: string,
  kind: CaptureDownloadKind = 'screenshot'
): boolean {
  const clean = sanitizeScreenshotBase64(base64);
  if (clean.length < 100) return false;

  const safeName = agentLabel.replace(/[^\w.-]+/g, '_').slice(0, 64) || 'agent';
  const stamp = new Date().toISOString().replace(/[:.]/g, '-');
  const blob = base64ToBlob(clean, 'image/jpeg');
  const url = URL.createObjectURL(blob);
  const a = document.createElement('a');
  a.href = url;
  a.download = `${kind}-${safeName}-${stamp}.jpg`;
  a.rel = 'noopener';
  document.body.appendChild(a);
  a.click();
  a.remove();
  URL.revokeObjectURL(url);
  return true;
}

function base64ToBlob(b64: string, mime: string): Blob {
  const binary = atob(b64);
  const bytes = new Uint8Array(binary.length);
  for (let i = 0; i < binary.length; i++) bytes[i] = binary.charCodeAt(i);
  return new Blob([bytes], { type: mime });
}