驯服 AI 造成的代码垃圾：用“深模块”哲学与架构重构重塑代码库

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// 只展示问题形态，类型定义省略
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export function validateCartItems(items: CartItem[]) {
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  if (!items || items.length === 0) throw new Error("购物车为空");
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  return items.filter((item) => item.quantity > 0);
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}
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export function computeOrderTotal(items: CartItem[], couponRate: number) {
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  const sum = items.reduce(
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    (total, item) => total + item.price * item.quantity,
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    0,
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  );
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  return sum * (1 - couponRate);
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}
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export async function deductInventoryApi(
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  api: InventoryService,
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  items: CartItem[],
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) {
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  return api.batchDeduct(items);
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}
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async function handleCheckoutFlow(cart, coupon, inventoryApi, paymentApi) {
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  const validItems = validateCartItems(cart.items);
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  const total = computeOrderTotal(validItems, coupon.rate);
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  await deductInventoryApi(inventoryApi, validItems);
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  try {
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    await paymentApi.charge({ amount: total });
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  } catch (error) {
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    // 失败处理暴露在编排代码中；实际系统还必须定义补偿与幂等语义
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    await inventoryApi.rollback(validItems);
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    throw error;
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  }
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}

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export interface OrderFulfillment {
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  checkout(command: CheckoutCommand): Promise<CheckoutResult>;
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}
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export interface CheckoutCommand {
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  userId: string;
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  cartItems: Array<{ sku: string; quantity: number; unitPrice: number }>;
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  couponCode?: string;
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  paymentToken: string;
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}
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export class OrderFulfillmentModule implements OrderFulfillment {
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  constructor(
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    private readonly paymentGateway: PaymentAdapter,
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    private readonly warehouse: InventoryAdapter,
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    private readonly orderRepo: OrderRepository,
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  ) {}
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  async checkout(command: CheckoutCommand): Promise<CheckoutResult> {
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    this.assertValidItems(command.cartItems);
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    const reservation = await this.warehouse.reserve(command.cartItems);
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    const totalAmount = this.calculateFinalAmount(
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      command.cartItems,
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      command.couponCode,
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    );
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    const paymentReceipt = await this.paymentGateway.charge({
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      token: command.paymentToken,
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      amount: totalAmount,
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      idempotencyKey: reservation.id,
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    });
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    const order = await this.orderRepo.saveOrder({
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      userId: command.userId,
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      items: command.cartItems,
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      total: totalAmount,
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      paymentId: paymentReceipt.id,
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      status: "CONFIRMED",
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    });
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    return {
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      success: true,
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      orderId: order.id,
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      receiptUrl: paymentReceipt.url,
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    };
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  }
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  private assertValidItems(items: CheckoutCommand["cartItems"]) {
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    if (!items || items.length === 0)
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      throw new InvalidCartException("Cart is empty");
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  }
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  private calculateFinalAmount(
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    items: CheckoutCommand["cartItems"],
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    couponCode?: string,
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  ): number {
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    // 为突出模块边界，示例省略优惠券规则与价格校验。
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    return items.reduce(
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      (total, item) => total + item.unitPrice * item.quantity,
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      0,
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    );
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  }
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}