export type StockQtyRoundMode = "CEILING" | "FLOOR";
export type StockQtyRoundSource = "CREATE" | "QC";

export type StockQtyRoundChoice = {
  mode: StockQtyRoundMode;
  before: number;
  after: number;
};

/** FP-MTMS Version Checklist | Functions Ref. No. 56 | v1.0.3 | 2026-09-10 */
export function previewPoBatchStockQty(
  orderM18Qty: number,
  orderStockQty: number,
  batchM18Qty: number,
): number {
  if (!Number.isFinite(orderM18Qty) || orderM18Qty === 0) {
    return Number(batchM18Qty.toFixed(2));
  }
  return Number(((batchM18Qty * orderStockQty) / orderM18Qty).toFixed(2));
}

export function isNotIntegerQty(qty: number): boolean {
  if (!Number.isFinite(qty)) return false;
  return Math.abs(qty - Math.round(qty)) > 1e-9;
}

/**
 * FP-MTMS Version Checklist | Functions Ref. No. 56 | v1.0.3 | 2026-09-10
 * PO 收貨／品檢：pending 或 escalated 且庫存數量非整數時需選擇 CEILING / FLOOR
 */
export function needsPoQcStockQtyRound(
  purchaseOrderLineId: number | null | undefined,
  status: string | null | undefined,
  acceptedQty: number | null | undefined,
): boolean {
  if (!purchaseOrderLineId) return false;
  const silStatus = (status ?? "").toLowerCase().trim();
  if (silStatus !== "pending" && silStatus !== "escalated") return false;
  return isNotIntegerQty(Number(acceptedQty ?? 0));
}

/** FP-MTMS Version Checklist | Functions Ref. No. 56 | v1.0.3 | 2026-09-10 */
export function roundStockQty(before: number, mode: StockQtyRoundMode): number {
  if (mode === "CEILING") return Math.ceil(before);
  return Math.floor(before);
}