const SAFE_DOCUMENT_CATEGORIES = new Set([
  "vat_invoice",
  "full_vat_invoice",
  "electronic_train_ticket",
]);

function normalizeSafeMetaString(value, maxLength = 64) {
  if (typeof value !== "string") return null;
  const normalized = value.trim();
  return normalized ? normalized.slice(0, maxLength) : null;
}

function mapInvoiceDocumentMeta(invoice) {
  const result = invoice?.ocr_result?.result_json;
  const category = normalizeSafeMetaString(result?.documentCategory);
  return {
    documentCategory: SAFE_DOCUMENT_CATEGORIES.has(category) ? category : null,
    documentSubtype: normalizeSafeMetaString(result?.documentSubtype),
  };
}

module.exports = { mapInvoiceDocumentMeta };