export function unitAskFor(displayUnit) {
  if (displayUnit === "unit") return "¿Cuántas unidades querés?";
  if (displayUnit === "g") return "¿Cuántos gramos querés?";
  return "¿Cuántos kilos querés?";
}

export function unitDisplay(unit) {
  if (unit === "unit") return "unidades";
  if (unit === "g") return "gramos";
  return "kilos";
}

export function inferDefaultUnit({ name, categories }) {
  const n = String(name || "").toLowerCase();
  const cats = Array.isArray(categories) ? categories : [];
  const hay = (re) =>
    cats.some((c) => re.test(String(c?.name || "")) || re.test(String(c?.slug || ""))) || re.test(n);
  if (
    hay(/\b(vino|vinos|bebida|bebidas|cerveza|cervezas|gaseosa|gaseosas|whisky|ron|gin|vodka|fernet)\b/i)
  ) {
    return "unit";
  }
  return "kg";
}

export function normalizeUnit(unit) {
  if (!unit) return null;
  const u = String(unit).toLowerCase();
  if (u === "kg" || u === "kilo" || u === "kilos") return "kg";
  if (u === "g" || u === "gramo" || u === "gramos") return "g";
  if (u === "unidad" || u === "unidades" || u === "unit") return "unit";
  return null;
}

export function resolveQuantity({ quantity, unit, displayUnit }) {
  if (quantity == null || !Number.isFinite(Number(quantity)) || Number(quantity) <= 0) return null;
  const q = Number(quantity);
  const u = normalizeUnit(unit) || (displayUnit === "unit" ? "unit" : displayUnit === "g" ? "g" : "kg");
  if (u === "unit") {
    return { quantity: Math.round(q), unit: "unit", display_quantity: Math.round(q), display_unit: "unit" };
  }
  if (u === "g") return { quantity: Math.round(q), unit: "g", display_quantity: Math.round(q), display_unit: "g" };
  // kg -> gramos enteros
  return {
    quantity: Math.round(q * 1000),
    unit: "g",
    display_unit: "kg",
    display_quantity: q,
  };
}