feat(core-flows,medusa): Add API to update cart's customer (#10151)

what:

- adds an endpoint that updates a cart's customer

RESOLVES CMRC-718

packages/core/core-flows/src/cart/workflows/index.ts

@@ -7,6 +7,7 @@ export * from "./create-payment-collection-for-cart"
 export * from "./list-shipping-options-for-cart"
 export * from "./refresh-payment-collection"
 export * from "./update-cart"
+export * from "./update-cart-customer"
 export * from "./update-cart-promotions"
 export * from "./update-line-item-in-cart"
 export * from "./update-tax-lines"

packages/core/core-flows/src/cart/workflows/update-cart-customer.ts

@@ -0,0 +1,98 @@
+import { isDefined, MedusaError } from "@medusajs/framework/utils"
+import {
+  createStep,
+  createWorkflow,
+  StepResponse,
+  transform,
+  when,
+  WorkflowData,
+} from "@medusajs/framework/workflows-sdk"
+import { CustomerDTO } from "@medusajs/types"
+import { useQueryGraphStep } from "../../common"
+import { updateCartsStep } from "../steps"
+
+/**
+ * This step validates if cart should be updated
+ */
+export const validateCartCustomerUpdateStep = createStep(
+  "validate-cart-customer-update",
+  async function ({
+    cart,
+    customer,
+  }: {
+    cart: {
+      customer?: { id: string; has_account: boolean }
+    }
+    customer: CustomerDTO
+  }) {
+    // If cart customer is the same as the provided customer, succeed early
+    // Pass in a boolean to not perform a customer update
+    if (isDefined(cart.customer?.id) && cart.customer.id === customer.id) {
+      return new StepResponse(false)
+    }
+
+    // If the cart customer already has an account, we can safely assume that its already
+    // been assigned to a different customer. This falls under cart take over, which isn't being
+    // handled with this workflow
+    if (cart.customer?.has_account) {
+      throw new MedusaError(
+        MedusaError.Types.NOT_ALLOWED,
+        `Cannot update cart customer when its assigned to a different customer`
+      )
+    }
+
+    return new StepResponse(true)
+  }
+)
+
+export const updateCartCustomerWorkflowId = "update-cart-customer"
+/**
+ * This workflow updates cart's customer.
+ */
+export const updateCartCustomerWorkflow = createWorkflow(
+  updateCartCustomerWorkflowId,
+  (input: WorkflowData<{ id: string; customer_id: string }>) => {
+    const cartQuery = useQueryGraphStep({
+      entity: "cart",
+      filters: { id: input.id },
+      fields: [
+        "id",
+        "email",
+        "customer_id",
+        "customer.has_account",
+        "shipping_address.*",
+        "region.*",
+        "region.countries.*",
+      ],
+      options: { throwIfKeyNotFound: true },
+    }).config({ name: "get-cart" })
+
+    const cart = transform({ cartQuery }, ({ cartQuery }) => cartQuery.data[0])
+
+    const customerQuery = useQueryGraphStep({
+      entity: "customer",
+      filters: { id: input.customer_id },
+      fields: ["id", "email"],
+      options: { throwIfKeyNotFound: true },
+    }).config({ name: "get-customer" })
+
+    const customer = transform(
+      { customerQuery },
+      ({ customerQuery }) => customerQuery.data[0]
+    )
+
+    const shouldUpdate = validateCartCustomerUpdateStep({ cart, customer })
+
+    when({ shouldUpdate }, ({ shouldUpdate }) => !!shouldUpdate).then(() => {
+      const cartInput = transform({ cart, customer }, ({ cart, customer }) => [
+        {
+          id: cart.id,
+          customer_id: customer.id,
+          email: customer.email,
+        },
+      ])
+
+      updateCartsStep(cartInput)
+    })
+  }
+)