feat(core-flows,medusa): add endpoint to add/remove fulfillment providers to location (#8299)

what:

- add endpoint to add/remove fulfillment providers to location
- specs cleanup from previous PR

RESOLVES CC-259

packages/medusa/src/api/admin/stock-locations/[id]/fulfillment-providers/route.ts

@@ -0,0 +1,41 @@
+import { batchLinksWorkflow } from "@medusajs/core-flows"
+import { LinkMethodRequest } from "@medusajs/types"
+import { Modules } from "@medusajs/utils"
+
+import {
+  AuthenticatedMedusaRequest,
+  MedusaResponse,
+} from "../../../../../types/routing"
+import { refetchStockLocation } from "../../helpers"
+
+const buildLinks = (id, fulfillmentProviderIds: string[]) => {
+  return fulfillmentProviderIds.map((fulfillmentProviderId) => ({
+    [Modules.STOCK_LOCATION]: { stock_location_id: id },
+    [Modules.FULFILLMENT]: {
+      fulfillment_provider_id: fulfillmentProviderId,
+    },
+  }))
+}
+
+export const POST = async (
+  req: AuthenticatedMedusaRequest<LinkMethodRequest>,
+  res: MedusaResponse
+) => {
+  const { id } = req.params
+  const { add = [], remove = [] } = req.validatedBody
+
+  await batchLinksWorkflow(req.scope).run({
+    input: {
+      create: buildLinks(id, add),
+      delete: buildLinks(id, remove),
+    },
+  })
+
+  const stockLocation = await refetchStockLocation(
+    req.params.id,
+    req.scope,
+    req.remoteQueryConfig.fields
+  )
+
+  res.status(200).json({ stock_location: stockLocation })
+}

packages/medusa/src/api/admin/stock-locations/middlewares.ts

@@ -82,4 +82,15 @@ export const adminStockLocationRoutesMiddlewares: MiddlewareRoute[] = [
       ),
     ],
   },
+  {
+    method: ["POST"],
+    matcher: "/admin/stock-locations/:id/fulfillment-providers",
+    middlewares: [
+      validateAndTransformBody(createLinkBody()),
+      validateAndTransformQuery(
+        AdminGetStockLocationParams,
+        QueryConfig.retrieveTransformQueryConfig
+      ),
+    ],
+  },
 ]