/**
 * KPI.chicken_life = DOC − cumulative mortality (excludes harvest).
 * Stock akhir (in-house remaining) = chicken_life − harvest_total.
 */
export function stockAkhirFromKpi(
  kpi: { chicken_life?: number | null; harvest_total?: number | null } | null | undefined
): number | null {
  if (kpi?.chicken_life == null) return null;
  return Math.max(0, kpi.chicken_life - (kpi.harvest_total ?? 0));
}