function slugifyContentId(value, fallback = "item") {
  const normalized = String(value || "")
    .trim()
    .toLowerCase()
    .replace(/[^a-z0-9]+/g, "-")
    .replace(/^-+|-+$/g, "");

  return normalized || fallback;
}

function ensureUniqueIds(items, getExistingId, getSourceValue, fallbackPrefix) {
  const usedIds = new Set();

  return (Array.isArray(items) ? items : []).map((item, index) => {
    const existingId = String(getExistingId(item, index) || "").trim();
    let nextId = existingId || slugifyContentId(getSourceValue(item, index), `${fallbackPrefix}-${index + 1}`);
    let suffix = 2;

    while (usedIds.has(nextId)) {
      nextId = `${existingId || slugifyContentId(getSourceValue(item, index), fallbackPrefix)}-${suffix}`;
      suffix += 1;
    }

    usedIds.add(nextId);
    return {
      ...item,
      id: nextId,
    };
  });
}

module.exports = {
  slugifyContentId,
  ensureUniqueIds,
};