first upload all files

Modules/Coupon/Checkers/AlreadyApplied.php

@@ -0,0 +1,19 @@
+<?php
+
+namespace Modules\Coupon\Checkers;
+
+use Closure;
+use Modules\Cart\Facades\Cart;
+use Modules\Coupon\Exceptions\CouponAlreadyAppliedException;
+
+class AlreadyApplied
+{
+    public function handle($coupon, Closure $next)
+    {
+        if (Cart::couponAlreadyApplied($coupon)) {
+            throw new CouponAlreadyAppliedException;
+        }
+
+        return $next($coupon);
+    }
+}