feat(upsell): apply real cart discounts and track performance

app/Services/UpsellService.php

@@ -43,8 +43,18 @@ class UpsellService {
         }
 
         $price = floatval($product->get_price());
+        return $this->calculateDiscountedPrice($price, $upsell);
+    }
+
+    public function calculateDiscountedPrice($price, $upsell) {
+        $price = max(0, floatval($price));
+        if (!$upsell) {
+            return $price;
+        }
+
         if ($upsell->discount_type === 'percentage') {
-            return max(0, $price * (1 - floatval($upsell->discount_value) / 100));
+            $percent = max(0, min(100, floatval($upsell->discount_value)));
+            return max(0, $price * (1 - $percent / 100));
         }
 
         if ($upsell->discount_type === 'fixed') {
@@ -54,6 +64,31 @@ class UpsellService {
         return $price;
     }
 
+    public function getById($id) {
+        return $this->upsellRepository->getById((int) $id);
+    }
+
+    public function isValidForCart($upsell, $cart) {
+        return $cart && !$cart->is_empty() && $this->cartMatchesTrigger($upsell, $cart);
+    }
+
+    public function canApplyToProduct($upsell, $productId, $variationId = 0) {
+        if (!$upsell || !$upsell->isActive()) {
+            return false;
+        }
+
+        $targetProductId = (int) $upsell->target_product_id;
+        return $targetProductId > 0 && ($targetProductId === (int) $productId || $targetProductId === (int) $variationId);
+    }
+
+    public function incrementImpression($upsellId) {
+        return $this->upsellRepository->incrementImpression((int) $upsellId);
+    }
+
+    public function incrementConversion($upsellId) {
+        return $this->upsellRepository->incrementConversion((int) $upsellId);
+    }
+
     public function getTriggerLabel($upsell) {
         switch ($upsell->trigger_type) {
             case 'product':