updated attach

server/src/internal/billing/v2/actions/attach/compute/finalizeAttachPlan.ts

@@ -1,18 +1,25 @@
-import type { AttachBillingContext, AutumnBillingPlan } from "@autumn/shared";
+import type {
+	AttachBillingContext,
+	AttachParamsV0,
+	AutumnBillingPlan,
+} from "@autumn/shared";
 import type { AutumnContext } from "@/honoUtils/HonoEnv";
 import { finalizeLineItems } from "@/internal/billing/v2/compute/finalize/finalizeLineItems";
 
 /**
- * Finalizes the attach billing plan by processing line items.
+ * Finalizes the attach billing plan by processing line items
+ * and applying attach-specific guards.
  */
 export const finalizeAttachPlan = ({
 	ctx,
 	plan,
 	attachBillingContext,
+	params,
 }: {
 	ctx: AutumnContext;
 	plan: AutumnBillingPlan;
 	attachBillingContext: AttachBillingContext;
+	params: AttachParamsV0;
 }): AutumnBillingPlan => {
 	plan.lineItems = finalizeLineItems({
 		ctx,
@@ -21,5 +28,10 @@ export const finalizeAttachPlan = ({
 		autumnBillingPlan: plan,
 	});
 
+	// Guard: if billing_behavior is 'next_cycle_only', clear line items (skip proration charges)
+	if (params.billing_behavior === "next_cycle_only") {
+		plan.lineItems = [];
+	}
+
 	return plan;
 };