Feat(medusa): handle reservation quantity update for line items (#3484)

**What**
-  Raise exception if a reservation is updated or created to have larger quantity than is unfulfilled for a line-item

Fixes CORE-1249

packages/medusa/src/api/routes/admin/reservations/create-reservation.ts

@@ -1,6 +1,8 @@
 import { IsNumber, IsObject, IsOptional, IsString } from "class-validator"
+import { isDefined } from "medusa-core-utils"
 import { EntityManager } from "typeorm"
 import { IInventoryService } from "../../../../interfaces"
+import { validateUpdateReservationQuantity } from "./utils/validate-reservation-quantity"
 
 /**
  * @oas [post] /admin/reservations
@@ -69,6 +71,17 @@ export default async (req, res) => {
   const inventoryService: IInventoryService =
     req.scope.resolve("inventoryService")
 
+  if (isDefined(validatedBody.line_item_id)) {
+    await validateUpdateReservationQuantity(
+      validatedBody.line_item_id,
+      validatedBody.quantity,
+      {
+        lineItemService: req.scope.resolve("lineItemService"),
+        inventoryService: req.scope.resolve("inventoryService"),
+      }
+    )
+  }
+
   const reservation = await manager.transaction(async (manager) => {
     return await inventoryService
       .withTransaction(manager)

packages/medusa/src/api/routes/admin/reservations/update-reservation.ts

@@ -1,6 +1,9 @@
 import { IsNumber, IsObject, IsOptional, IsString } from "class-validator"
+import { isDefined, MedusaError } from "medusa-core-utils"
 import { EntityManager } from "typeorm"
 import { IInventoryService } from "../../../../interfaces"
+import { LineItemService } from "../../../../services"
+import { validateUpdateReservationQuantity } from "./utils/validate-reservation-quantity"
 
 /**
  * @oas [post] /admin/reservations/{id}
@@ -69,10 +72,24 @@ export default async (req, res) => {
   }
 
   const manager: EntityManager = req.scope.resolve("manager")
+  const lineItemService: LineItemService = req.scope.resolve("lineItemService")
 
   const inventoryService: IInventoryService =
     req.scope.resolve("inventoryService")
 
+  const reservation = await inventoryService.retrieveReservationItem(id)
+
+  if (reservation.line_item_id && isDefined(validatedBody.quantity)) {
+    await validateUpdateReservationQuantity(
+      reservation.line_item_id,
+      validatedBody.quantity - reservation.quantity,
+      {
+        lineItemService,
+        inventoryService,
+      }
+    )
+  }
+
   const result = await manager.transaction(async (manager) => {
     await inventoryService
       .withTransaction(manager)

packages/medusa/src/api/routes/admin/reservations/utils/validate-reservation-quantity.ts

@@ -0,0 +1,31 @@
+import { MedusaError } from "medusa-core-utils"
+import { IInventoryService } from "../../../../../interfaces"
+import { LineItemService } from "../../../../../services"
+
+export const validateUpdateReservationQuantity = async (
+  lineItemId: string,
+  quantityUpdate: number,
+  context: {
+    lineItemService: LineItemService
+    inventoryService: IInventoryService
+  }
+) => {
+  const { lineItemService, inventoryService } = context
+  const [reservationItems] = await inventoryService.listReservationItems({
+    line_item_id: lineItemId,
+  })
+
+  const totalQuantity = reservationItems.reduce(
+    (acc, cur) => acc + cur.quantity,
+    quantityUpdate
+  )
+
+  const lineItem = await lineItemService.retrieve(lineItemId)
+
+  if (totalQuantity > lineItem.quantity - (lineItem.fulfilled_quantity || 0)) {
+    throw new MedusaError(
+      MedusaError.Types.INVALID_DATA,
+      "The reservation quantity cannot be greater than the unfulfilled line item quantity"
+    )
+  }
+}