Added cart rule validation function which validates the cart rule and added unique coupon check while creating or updating couponable cart rule

config/app.php

@@ -245,7 +245,7 @@ return [
         Webkul\Sales\Providers\SalesServiceProvider::class,
         Webkul\Tax\Providers\TaxServiceProvider::class,
         Webkul\API\Providers\APIServiceProvider::class,
-        Webkul\Discount\Providers\DiscountServiceProvider::class,
+        Webkul\Discount\Providers\DiscountServiceProvider::class
     ],
 
     /*

packages/Webkul/Admin/src/Resources/lang/en/app.php

@@ -864,7 +864,8 @@ return [
             'coupon-failed' => 'Coupon failed to apply',
             'no-coupon' => '* Coupon not applicable',
             'coupon-removed' => 'Coupon removed successfully',
-            'coupon-remove-failed' => 'Coupon removal failed'
+            'coupon-remove-failed' => 'Coupon removal failed',
+            'duplicate-coupon' => 'Coupon already exists, please try again with a different coupon'
         ],
 
         'catalog' => [

packages/Webkul/Discount/src/Helpers/Discount.php

@@ -136,25 +136,26 @@ abstract class Discount
         ]);
 
         if (count($existingRule)) {
-            // $this->clearDiscount();
-
             if ($existingRule->first()->cart_rule_id != $rule->id) {
                 $existingRule->first()->update([
                     'cart_rule_id' => $rule->id
                 ]);
 
+                $this->clearDiscount();
+
                 $this->updateCartItemAndCart($rule);
 
                 return true;
             }
         } else {
-            // $this->clearDiscount();
 
             $this->cartRuleCart->create([
                 'cart_id' => $cart->id,
                 'cart_rule_id' => $rule->id
             ]);
 
+            $this->clearDiscount();
+
             $this->updateCartItemAndCart($rule);
 
             return true;
@@ -272,7 +273,7 @@ abstract class Discount
     /**
      * To find the max worth item in current cart instance
      *
-     * @return Array
+     * @return array
      */
     public function maxWorthItem()
     {
@@ -296,6 +297,27 @@ abstract class Discount
         return $maxWorthItem;
     }
 
+    /**
+     * Validate the currently applied cart rule
+     *
+     * @return boolean
+     */
+    public function validateRule($rule)
+    {
+        $applicability = $this->checkApplicability($rule);
+
+        if ($applicability) {
+            if ($rule->status) {
+                return true;
+            } else {
+                return false;
+            }
+        } else {
+            return false;
+        }
+    }
+
+
     /**
      * Checks the rule against the current cart instance whether rule conditions are applicable
      * or not

packages/Webkul/Discount/src/Helpers/NonCouponAbleRule.php

@@ -32,13 +32,25 @@ class NonCouponAbleRule extends Discount
             ]);
         }
 
-        $alreadyAppliedRule = $this->cartRuleCart->findWhere([
+        $alreadyAppliedCartRuleCart = $this->cartRuleCart->findWhere([
             'cart_id' => $cart->id,
         ]);
 
 
-        if (count($alreadyAppliedRule)) {
-            $alreadyAppliedRule = $alreadyAppliedRule->first()->cart_rule;
+        if (count($alreadyAppliedCartRuleCart)) {
+            $alreadyAppliedRule = $alreadyAppliedCartRuleCart->first()->cart_rule;
+
+            $validated = $this->validateRule($alreadyAppliedRule);
+
+            if (! $alreadyAppliedRule->use_coupon && ! $validated) {
+                // if the validation fails then the cart rule gets deleted from cart rule cart
+                $alreadyAppliedRule->delete();
+
+                // all discount is cleared fro mthe cart and cart items table
+                $this->clearDiscount();
+
+                return null;
+            }
 
             if ($alreadyAppliedRule->use_coupon) {
                 return null;

packages/Webkul/Discount/src/Http/Controllers/CartRuleController.php

@@ -190,6 +190,16 @@ class CartRuleController extends Controller
             // save the coupon used in coupon section
             $coupons['code'] = $data['code'];
 
+            $couponExists = $this->cartRuleCoupon->findWhere([
+                'code' => $coupons['code']
+            ]);
+
+            if ($couponExists->count()) {
+                session()->flash('warning', trans('admin::app.promotion.status.duplicate-coupon'));
+
+                return redirect()->back();
+            }
+
             // set coupon usage per customer same as per_customer limit which is disabled for now
             $coupons['usage_per_customer'] = $data['per_customer']; //0 is for unlimited usage
             // unset coupon code from coupon section
@@ -390,6 +400,18 @@ class CartRuleController extends Controller
 
             $coupons['code'] = $data['code'];
 
+            $couponExists = $this->cartRuleCoupon->findWhere([
+                'code' => $coupons['code']
+            ]);
+
+            if ($couponExists->count()) {
+                if ($couponExists->first()->cart_rule_id != $id) {
+                    session()->flash('warning', trans('admin::app.promotion.status.duplicate-coupon'));
+
+                    return redirect()->back();
+                }
+            }
+
             unset($data['code']);
             // } else {
             //     $data['auto_generation'] = 1;