Add per-item order pricing

prisma/migrations/0008_order_item_pricing/migration.sql

@@ -0,0 +1,2 @@
+ALTER TABLE "OrderItem"
+ADD COLUMN "unitPrice" DECIMAL(14, 2);

prisma/schema.prisma

@@ -273,6 +273,7 @@ model OrderItem {
   product     Product? @relation(fields: [productId], references: [id])
   productName String
   quantity    Decimal  @db.Decimal(14, 3)
+  unitPrice   Decimal? @db.Decimal(14, 2)
   createdAt   DateTime @default(now())
 }
 

src/resolvers.js

@@ -25,6 +25,10 @@ function toFloat(value) {
   return value == null ? null : Number(value);
 }
 
+function roundMoney(value) {
+  return Math.round((Number(value) + Number.EPSILON) * 100) / 100;
+}
+
 function requireUser(context) {
   if (!context.user) {
     throw new Error('Authentication required.');
@@ -1365,19 +1369,75 @@ export const resolvers = {
       const manager = requireManagerAccess(context);
       const existingOrder = await context.prisma.order.findUnique({
         where: { id: input.orderId },
+        include: {
+          items: true,
+        },
       });
       assertManagerCanAccessOrder(existingOrder);
 
-      const order = await context.prisma.order.update({
+      if (!existingOrder.items.length) {
+        throw new Error('Order has no items to price.');
+      }
+
+      const deliveryFee = Number(input.deliveryFee);
+      if (!Number.isFinite(deliveryFee) || deliveryFee < 0) {
+        throw new Error('Delivery fee must be zero or greater.');
+      }
+
+      const orderItemIds = new Set(existingOrder.items.map((item) => item.id));
+      const itemPriceMap = new Map();
+
+      for (const itemPrice of input.itemPrices) {
+        if (itemPriceMap.has(itemPrice.itemId)) {
+          throw new Error('Duplicate item pricing entries are not allowed.');
+        }
+
+        if (!orderItemIds.has(itemPrice.itemId)) {
+          throw new Error('Pricing can only be set for items from this order.');
+        }
+
+        const unitPrice = Number(itemPrice.unitPrice);
+        if (!Number.isFinite(unitPrice) || unitPrice < 0) {
+          throw new Error('Unit price must be zero or greater.');
+        }
+
+        itemPriceMap.set(itemPrice.itemId, roundMoney(unitPrice));
+      }
+
+      if (itemPriceMap.size !== existingOrder.items.length) {
+        throw new Error('Pricing must be provided for every order item.');
+      }
+
+      const totalProductsPrice = existingOrder.items.reduce(
+        (sum, item) => sum + (Number(item.quantity) * itemPriceMap.get(item.id)),
+        0,
+      );
+      const totalPrice = roundMoney(totalProductsPrice + deliveryFee);
+
+      const order = await context.prisma.$transaction(async (tx) => {
+        for (const item of existingOrder.items) {
+          await tx.orderItem.update({
+            where: { id: item.id },
+            data: {
+              unitPrice: itemPriceMap.get(item.id),
+            },
+          });
+        }
+
+        return tx.order.update({
           where: { id: input.orderId },
           data: {
             managerId: manager.id,
             status: 'WAITING_DOUBLE_CONFIRM',
-          deliveryTerms: input.deliveryTerms,
-          deliveryFee: input.deliveryFee,
-          totalPrice: input.totalPrice,
+            clientApproved: null,
+            managerApproved: null,
+            blockReason: null,
+            deliveryTerms: normalizeOptionalText(input.deliveryTerms),
+            deliveryFee: roundMoney(deliveryFee),
+            totalPrice,
           },
         });
+      });
 
       await appendOrderEvent(context.prisma, order.id, 'WAITING_DOUBLE_CONFIRM', manager.id, 'Offer is published by manager');
       await notifyOrderStakeholders(context, order, 'WAITING_DOUBLE_CONFIRM', 'Offer is published by manager');
@@ -1636,6 +1696,12 @@ export const resolvers = {
 
   OrderItem: {
     quantity: (item) => toFloat(item.quantity),
+    unitPrice: (item) => toFloat(item.unitPrice),
+    lineTotal: (item) => (
+      item.unitPrice == null
+        ? null
+        : roundMoney(Number(item.quantity) * Number(item.unitPrice))
+    ),
   },
 
   BonusTransaction: {

src/schema.graphql

@@ -232,6 +232,8 @@ type OrderItem {
   productId: ID
   productName: String!
   quantity: Float!
+  unitPrice: Float
+  lineTotal: Float
 }
 
 type OrderStatusEvent {
@@ -428,9 +430,14 @@ input SubmitCalculationOrderInput {
 
 input SetOrderOfferInput {
   orderId: ID!
+  itemPrices: [OrderItemPriceInput!]!
   deliveryTerms: String!
   deliveryFee: Float!
-  totalPrice: Float!
+}
+
+input OrderItemPriceInput {
+  itemId: ID!
+  unitPrice: Float!
 }
 
 input BlockOrderInput {