feat: add invoice

app/Http/Controllers/BillingController.php

@@ -51,11 +51,24 @@ class BillingController extends Controller
         ];
 
         if ($creditProduct->type === CreditProductType::MONTHLY) {
+            if ($user->subscribed('default')) {
+                return response()->json([
+                    'message' => __('api.billing.active_subscription_exists'),
+                ], 409);
+            }
+
             $checkout = $user
                 ->newSubscription('default', $creditProduct->stripe_price_id)
                 ->withMetadata($metadata)
                 ->checkout($sessionOptions);
         } else {
+            $sessionOptions['invoice_creation'] = [
+                'enabled' => true,
+                'invoice_data' => [
+                    'metadata' => $metadata,
+                ],
+            ];
+
             $checkout = $user->checkout([
                 $creditProduct->stripe_price_id => 1,
             ], $sessionOptions);
@@ -83,6 +96,12 @@ class BillingController extends Controller
         $user = $request->user();
         $this->ensureStripeCustomer($user);
 
+        if (! $user->subscribed('default')) {
+            return response()->json([
+                'message' => __('api.billing.no_active_subscription'),
+            ], 409);
+        }
+
         $portalUrl = $user->billingPortalUrl($this->redirectUrl('portal'));
 
         return response()->json([