物流对账单

packages/domain/src/index.test.ts

@@ -2,6 +2,7 @@ import { describe, expect, it } from 'vitest';
 import {
   calcBenefitAmount,
   calcRedeemSettleAmount,
+  calcLogisticsFeeByBottles,
   validateMinPurchase,
   validateRedeemAmount,
   allocateBenefitCoupons,
@@ -67,6 +68,37 @@ describe('calcRedeemSettleAmount', () => {
   });
 });
 
+describe('calcLogisticsFeeByBottles', () => {
+  const xfx = {
+    baseBottles: 2,
+    baseFee: 6,
+    extraBottleFee: 2,
+    boxBottles: 6,
+    boxFee: 14,
+  };
+
+  it('charges base for 1~2 bottles', () => {
+    expect(calcLogisticsFeeByBottles(1, xfx)).toBe(6);
+    expect(calcLogisticsFeeByBottles(2, xfx)).toBe(6);
+  });
+
+  it('adds extra bottle fee', () => {
+    expect(calcLogisticsFeeByBottles(3, xfx)).toBe(8);
+    expect(calcLogisticsFeeByBottles(5, xfx)).toBe(12);
+  });
+
+  it('uses box fee for full boxes', () => {
+    expect(calcLogisticsFeeByBottles(6, xfx)).toBe(14);
+    expect(calcLogisticsFeeByBottles(12, xfx)).toBe(28);
+  });
+
+  it('combines boxes with remainder ladder', () => {
+    expect(calcLogisticsFeeByBottles(7, xfx)).toBe(20);
+    expect(calcLogisticsFeeByBottles(8, xfx)).toBe(20);
+    expect(calcLogisticsFeeByBottles(9, xfx)).toBe(22);
+  });
+});
+
 describe('allocateBenefitCoupons', () => {
   const coupons = [
     { id: '1', balance: 300, createdAt: 1 },

packages/domain/src/index.ts

@@ -95,6 +95,47 @@ export function calcRedeemSettleAmount(amount: number, settlementRate: number):
   return Math.round(amount * settlementRate * 100) / 100;
 }
 
+/** 物流（快递）按瓶计价规则，如小飞侠：2瓶6元、加一瓶+2元、6瓶一箱14元 */
+export type LogisticsPricingRule = {
+  baseBottles: number;
+  baseFee: number;
+  extraBottleFee: number;
+  boxBottles?: number;
+  boxFee?: number;
+};
+
+function roundMoney(n: number): number {
+  return Math.round(n * 100) / 100;
+}
+
+function calcLogisticsBottleLadder(quantity: number, rule: LogisticsPricingRule): number {
+  const qty = Math.floor(quantity);
+  if (qty <= 0) return 0;
+  if (qty <= rule.baseBottles) return rule.baseFee;
+  return rule.baseFee + (qty - rule.baseBottles) * rule.extraBottleFee;
+}
+
+/**
+ * 按承运商计价标准计算单票物流费。
+ * 配置了箱规时：整箱按 boxFee，余瓶按「起送瓶数/加瓶」阶梯。
+ */
+export function calcLogisticsFeeByBottles(quantity: number, rule: LogisticsPricingRule): number {
+  const qty = Math.floor(Number(quantity) || 0);
+  if (qty <= 0) return 0;
+  if (!(rule.baseBottles > 0) || !(rule.baseFee >= 0) || !(rule.extraBottleFee >= 0)) {
+    throw new Error('计价标准不完整');
+  }
+
+  const boxBottles = rule.boxBottles && rule.boxBottles > 0 ? rule.boxBottles : 0;
+  const boxFee = rule.boxFee != null && rule.boxFee >= 0 ? rule.boxFee : null;
+  if (boxBottles > 0 && boxFee != null) {
+    const boxes = Math.floor(qty / boxBottles);
+    const rem = qty % boxBottles;
+    return roundMoney(boxes * boxFee + calcLogisticsBottleLadder(rem, rule));
+  }
+  return roundMoney(calcLogisticsBottleLadder(qty, rule));
+}
+
 export function generateUserNo(): string {
   const suffix = Math.floor(10000000 + Math.random() * 90000000);
   return `DK${suffix}`;