const invalidApiResponse = /unexpected token|doctype|not valid json|json parse|syntaxerror/i;
const htmlResponse = /<html|<!doctype|<body/i;

export const formatOperatorError = (error: unknown, fallback: string): string => {
  const raw = error instanceof Error ? error.message : String(error || "");
  const normalized = raw.trim();

  if (!normalized) return fallback;
  if (invalidApiResponse.test(normalized) || htmlResponse.test(normalized)) {
    return `${fallback} De backendbron gaf geen geldige API-respons.`;
  }
  if (normalized.length > 240) {
    return `${normalized.slice(0, 237)}...`;
  }
  return normalized;
};