feat(backend): implement pricing engine for loyalty points and 3-level promotions

apps/backend/prisma/schema.prisma

@@ -82,6 +82,7 @@ model Customer {
   pictureUrl  String?
   email       String?
   phone       String?
+  points      Int      @default(0)
   orders      Order[]
   reviews     Review[]
   createdAt   DateTime @default(now())
@@ -116,12 +117,27 @@ model Coupon {
   updatedAt   DateTime  @updatedAt
 }
 
+model Promotion {
+  id          Int       @id @default(autoincrement())
+  name        String
+  level       Int
+  type        String
+  value       Float
+  minPurchase Float     @default(0)
+  isActive    Boolean   @default(true)
+  startDate   DateTime?
+  endDate     DateTime?
+  createdAt   DateTime  @default(now())
+  updatedAt   DateTime  @updatedAt
+}
+
 model StoreSettings {
   id                Int      @id @default(1)
   shippingFee       Float    @default(35)
   bankName          String   @default("KASIKORNBANK (KBANK)")
   bankAccountName   String   @default("HomAroma Co., Ltd.")
   bankAccountNumber String   @default("012-3-45678-9")
+  pointsEarnRate    Float    @default(1.0)
   updatedAt         DateTime @updatedAt
 }
 
@@ -131,10 +147,22 @@ model Order {
   customerEmail   String
   customerPhone   String
   shippingAddress String
-  totalAmount     Float
+  
-  shippingFee     Float       @default(35)
+  subtotal        Float       @default(0)
+  promoLevel1Name String?
+  promoLevel1Disc Float       @default(0)
+  promoLevel2Name String?
+  promoLevel2Disc Float       @default(0)
+  
   couponCode      String?
   discountAmount  Float       @default(0)
+  
+  pointsUsed      Int         @default(0)
+  pointsDiscount  Float       @default(0)
+  pointsEarned    Int         @default(0)
+  
+  shippingFee     Float       @default(35)
+  totalAmount     Float
   status          String      @default("PENDING_PAYMENT")
   paymentSlipUrl  String?
   

apps/backend/src/index.ts

@@ -19,6 +19,7 @@ import { lazadaOrderRoute } from "./routes/lazadaOrder";
 import { customersRoute } from "./routes/customers";
 import { couponsRoute } from "./routes/coupons";
 import { reviewsRoute } from "./routes/reviews";
+import { promotionsRoute } from "./routes/promotions";
 const PORT = process.env.PORT ? parseInt(process.env.PORT) : 3000;
 const CORS_ORIGIN = process.env.CORS_ORIGIN || "http://localhost:5173";
 const JWT_SECRET = process.env.JWT_SECRET || "homaroma_secret_2026_scent";
@@ -82,7 +83,7 @@ const app = new Elysia()
     return file;
   })
   .group("/api", (app) =>
-    app.use(authRoute).use(categoriesRoute).use(productsRoute).use(uploadRoute).use(heroRoute).use(ordersRoute).use(settingsRoute).use(articlesRoute).use(tiktokRoute).use(rawMaterialsRoute).use(shopeeRoute).use(tiktokOrderRoute).use(lazadaOrderRoute).use(customersRoute).use(couponsRoute).use(reviewsRoute)
+    app.use(authRoute).use(categoriesRoute).use(productsRoute).use(uploadRoute).use(heroRoute).use(ordersRoute).use(settingsRoute).use(articlesRoute).use(tiktokRoute).use(rawMaterialsRoute).use(shopeeRoute).use(tiktokOrderRoute).use(lazadaOrderRoute).use(customersRoute).use(couponsRoute).use(reviewsRoute).use(promotionsRoute)
   )
   .listen(PORT);
 

apps/backend/src/routes/orders.ts

@@ -22,6 +22,24 @@ export const ordersRoute = new Elysia({ prefix: "/orders" })
   .post("/", async ({ body, set }) => {
     try {
       const data = body as any;
+      const settings = await prisma.storeSettings.findFirst()
+      const earnRate = settings?.pointsEarnRate || 1.0
+      const netAmount = data.totalAmount - data.shippingFee
+      const pointsEarned = Math.floor(Math.max(0, netAmount) * earnRate)
+
+      if (data.customerId && data.pointsUsed && data.pointsUsed > 0) {
+        // Verify customer has enough points
+        const customer = await prisma.customer.findUnique({ where: { id: data.customerId } })
+        if (!customer || customer.points < data.pointsUsed) {
+          set.status = 400
+          return { error: "Insufficient points" }
+        }
+        // Deduct points immediately
+        await prisma.customer.update({
+          where: { id: data.customerId },
+          data: { points: { decrement: data.pointsUsed } }
+        })
+      }
 
       const order = await prisma.order.create({
         data: {
@@ -30,10 +48,18 @@ export const ordersRoute = new Elysia({ prefix: "/orders" })
           customerEmail: data.customerEmail,
           customerPhone: data.customerPhone,
           shippingAddress: data.shippingAddress,
-          totalAmount: data.totalAmount,
+          subtotal: data.subtotal || 0,
-          shippingFee: data.shippingFee,
+          promoLevel1Name: data.promoLevel1Name,
+          promoLevel1Disc: data.promoLevel1Disc || 0,
+          promoLevel2Name: data.promoLevel2Name,
+          promoLevel2Disc: data.promoLevel2Disc || 0,
           couponCode: data.couponCode || null,
           discountAmount: data.discountAmount || 0,
+          pointsUsed: data.pointsUsed || 0,
+          pointsDiscount: data.pointsDiscount || 0,
+          pointsEarned: pointsEarned,
+          shippingFee: data.shippingFee,
+          totalAmount: data.totalAmount,
           items: {
             create: data.items.map((item: any) => ({
               productId: item.productId,
@@ -76,8 +102,15 @@ export const ordersRoute = new Elysia({ prefix: "/orders" })
       shippingAddress: t.String(),
       totalAmount: t.Number(),
       shippingFee: t.Number(),
+      subtotal: t.Optional(t.Number()),
+      promoLevel1Name: t.Optional(t.Nullable(t.String())),
+      promoLevel1Disc: t.Optional(t.Number()),
+      promoLevel2Name: t.Optional(t.Nullable(t.String())),
+      promoLevel2Disc: t.Optional(t.Number()),
       couponCode: t.Optional(t.Nullable(t.String())),
       discountAmount: t.Optional(t.Number()),
+      pointsUsed: t.Optional(t.Number()),
+      pointsDiscount: t.Optional(t.Number()),
       items: t.Array(t.Object({
         productId: t.Number(),
         variantId: t.Optional(t.Number()),
@@ -92,11 +125,31 @@ export const ordersRoute = new Elysia({ prefix: "/orders" })
   .patch("/:id/status", async ({ params: { id }, body, set }) => {
     try {
       const { status } = body as any;
-      return await prisma.order.update({
+      const order = await prisma.order.findUnique({ where: { id: Number(id) } });
+      
+      const updatedOrder = await prisma.order.update({
         where: { id: Number(id) },
         data: { status },
         include: { items: true }
       });
+
+      // Grant points if status becomes PAID and it wasn't PAID before
+      if (status === 'PAID' && order?.status !== 'PAID' && order?.customerId && order?.pointsEarned > 0) {
+        await prisma.customer.update({
+          where: { id: order.customerId },
+          data: { points: { increment: order.pointsEarned } }
+        });
+      }
+
+      // If status becomes CANCELLED, refund the points used
+      if (status === 'CANCELLED' && order?.status !== 'CANCELLED' && order?.customerId && order?.pointsUsed > 0) {
+        await prisma.customer.update({
+          where: { id: order.customerId },
+          data: { points: { increment: order.pointsUsed } }
+        });
+      }
+
+      return updatedOrder;
     } catch (err) {
       set.status = 500;
       return { error: "Failed to update order status" };

apps/backend/src/routes/promotions.ts

@@ -0,0 +1,20 @@
+import { Elysia, t } from "elysia";
+import prisma from "../lib/prisma";
+
+export const promotionsRoute = new Elysia({ prefix: "/promotions" })
+  .get("/active", async () => {
+    const now = new Date()
+    return await prisma.promotion.findMany({
+      where: {
+        isActive: true,
+        OR: [
+          { startDate: null },
+          { startDate: { lte: now } }
+        ],
+        AND: [
+          { OR: [{ endDate: null }, { endDate: { gte: now } }] }
+        ]
+      },
+      orderBy: { level: 'asc' }
+    });
+  });