const MAX_PUBLIC_AUDIT_SLUG_LENGTH = 120;

const transliterations: Record<string, string> = {
  ä: "ae",
  ö: "oe",
  ü: "ue",
  ß: "ss",
  æ: "ae",
  ø: "oe",
  å: "a",
};

export const toPublicAuditSlug = (companyName: string, domain: string) => {
  const input = `${companyName} ${domain}`.trim().toLowerCase();
  const normalized = input
    .replace(/[äöüßæøå]/g, (character) => transliterations[character] ?? character)
    .normalize("NFKD")
    .replace(/[\u0300-\u036f]/g, "")
    .replace(/[^a-z0-9]+/g, "-")
    .replace(/^-+|-+$/g, "")
    .replace(/-{2,}/g, "-")
    .slice(0, MAX_PUBLIC_AUDIT_SLUG_LENGTH)
    .replace(/-+$/g, "");

  return normalized.length > 0 ? normalized : "audit";
};

export const parsePublicAuditSlug = (slug: string) => {
  const normalized = slug.trim().toLowerCase();

  if (
    normalized.length === 0 ||
    normalized.length > MAX_PUBLIC_AUDIT_SLUG_LENGTH ||
    !/^[a-z0-9]+(?:-[a-z0-9]+)*$/.test(normalized)
  ) {
    return null;
  }

  return normalized;
};