feat(purchase): implement purchase limit enforcement and custom exception handling

app/Domains/Purchase/Services/UserPurchaseLimitService.php

@@ -4,11 +4,11 @@ namespace App\Domains\Purchase\Services;
 
 use App\Domains\Cart\Models\CartItem;
 use App\Domains\Catalog\Models\CatalogItem;
+use App\Domains\Purchase\Exceptions\PurchaseLimitExceededException;
 use App\Domains\Purchase\Models\Purchase;
 use App\Domains\Purchase\Models\PurchaseItem;
 use Illuminate\Support\Collection;
 use Illuminate\Support\Facades\DB;
-use Illuminate\Validation\ValidationException;
 
 class UserPurchaseLimitService
 {
@@ -18,6 +18,8 @@ class UserPurchaseLimitService
         int $requestedQuantity,
         ?int $excludedPurchaseId = null,
         ?int $excludedCartId = null,
+        int $heldQuantity = 0,
+        ?int $maximumAddableCeiling = null,
         string $field = 'quantity',
     ): void {
         DB::transaction(function () use (
@@ -26,6 +28,8 @@ class UserPurchaseLimitService
             $requestedQuantity,
             $excludedPurchaseId,
             $excludedCartId,
+            $heldQuantity,
+            $maximumAddableCeiling,
             $field,
         ): void {
             /** @var CatalogItem $catalogItem */
@@ -86,9 +90,20 @@ class UserPurchaseLimitService
                 ->sum('cantidad');
 
             if ($purchasedQuantity + $checkoutQuantity + $reservedCartQuantity + $requestedQuantity > $limit) {
-                throw ValidationException::withMessages([
-                    $field => __('api.purchase_limit.exceeded', ['max' => $limit]),
-                ]);
+                $remainingQuota = max(
+                    0,
+                    $limit - $purchasedQuantity - $checkoutQuantity - $reservedCartQuantity,
+                );
+
+                $maximumAddableQuantity = max(0, $remainingQuota - $heldQuantity);
+
+                throw new PurchaseLimitExceededException(
+                    $catalogItem,
+                    $maximumAddableCeiling === null
+                        ? $maximumAddableQuantity
+                        : min($maximumAddableQuantity, $maximumAddableCeiling),
+                    $field,
+                );
             }
         });
     }