feat(core-flows,medusa,types): add automatic-taxes to region + generate tax lines endpoint (#6667)

what:

- endpoint to generate tax lines
- update workflows to force calculate tax lines with a flag
- added automatic_taxes to region

packages/core-flows/src/definition/cart/steps/get-item-tax-lines.ts

@@ -9,6 +9,7 @@ import {
   TaxableItemDTO,
   TaxableShippingDTO,
 } from "@medusajs/types"
+import { MedusaError } from "@medusajs/utils"
 import { StepResponse, createStep } from "@medusajs/workflows-sdk"
 import { ModuleRegistrationName } from "../../../../../modules-sdk/dist"
 
@@ -16,14 +17,28 @@ interface StepInput {
   cart: CartWorkflowDTO
   items: CartLineItemDTO[]
   shipping_methods: CartShippingMethodDTO[]
+  force_tax_calculation?: boolean
 }
 
 function normalizeTaxModuleContext(
-  cart: CartWorkflowDTO
+  cart: CartWorkflowDTO,
+  forceTaxCalculation: boolean
 ): TaxCalculationContext | null {
   const address = cart.shipping_address
+  const shouldCalculateTax = forceTaxCalculation || cart.region?.automatic_taxes
 
-  if (!address || !address.country_code) {
+  if (!shouldCalculateTax) {
+    return null
+  }
+
+  if (forceTaxCalculation && !address?.country_code) {
+    throw new MedusaError(
+      MedusaError.Types.INVALID_DATA,
+      `country code is required to calculate taxes`
+    )
+  }
+
+  if (!address?.country_code) {
     return null
   }
 
@@ -83,12 +98,17 @@ export const getItemTaxLinesStepId = "get-item-tax-lines"
 export const getItemTaxLinesStep = createStep(
   getItemTaxLinesStepId,
   async (data: StepInput, { container }) => {
-    const { cart, items, shipping_methods: shippingMethods } = data
+    const {
+      cart,
+      items,
+      shipping_methods: shippingMethods,
+      force_tax_calculation: forceTaxCalculation = false,
+    } = data
     const taxService = container.resolve<ITaxModuleService>(
       ModuleRegistrationName.TAX
     )
 
-    const taxContext = normalizeTaxModuleContext(cart)
+    const taxContext = normalizeTaxModuleContext(cart, forceTaxCalculation)
 
     if (!taxContext) {
       return new StepResponse({

packages/core-flows/src/definition/cart/steps/update-tax-lines.ts

@@ -10,6 +10,7 @@ interface StepInput {
   cart_or_cart_id: CartWorkflowDTO | string
   items?: CartLineItemDTO[]
   shipping_methods?: CartShippingMethodDTO[]
+  force_tax_calculation?: boolean
 }
 
 export const updateTaxLinesStepId = "update-tax-lines-step"

packages/core-flows/src/definition/cart/workflows/update-tax-lines.ts

@@ -18,6 +18,8 @@ const cartFields = [
   "id",
   "currency_code",
   "email",
+  "region.id",
+  "region.automatic_taxes",
   "items.id",
   "items.variant_id",
   "items.product_id",
@@ -62,6 +64,7 @@ type WorkflowInput = {
   cart_or_cart_id: string | CartWorkflowDTO
   items?: CartLineItemDTO[]
   shipping_methods?: CartShippingMethodDTO[]
+  force_tax_calculation?: boolean
 }
 
 export const updateTaxLinesWorkflowId = "update-tax-lines"
@@ -79,6 +82,7 @@ export const updateTaxLinesWorkflow = createWorkflow(
         items: data.input.items || data.cart.items,
         shipping_methods:
           data.input.shipping_methods || data.cart.shipping_methods,
+        force_tax_calculation: data.input.force_tax_calculation,
       }))
     )