feat(cart): implement user purchase limit validation for cart items and add related tests

app/Domains/Cart/Models/Cart.php

@@ -7,6 +7,7 @@ use App\Domains\Catalog\Models\CatalogItem;
 use App\Domains\Catalog\Models\Inventory;
 use App\Domains\Catalog\Models\Variant;
 use App\Domains\Catalog\Services\CatalogInventoryService;
+use App\Domains\Purchase\Services\UserPurchaseLimitService;
 use App\Domains\Tenant\Models\Tenant;
 use Illuminate\Database\Eloquent\Attributes\Fillable;
 use Illuminate\Database\Eloquent\Factories\HasFactory;
@@ -86,6 +87,10 @@ class Cart extends Model
         return DB::transaction(function () use ($catalogItemId, $variantId, $quantity): CartItem {
             self::query()->whereKey($this->getKey())->lockForUpdate()->firstOrFail();
             $selectedItem = $this->resolveScopedItem($catalogItemId, $variantId, true);
+            $cartQuantity = (int) $this->items()
+                ->where('catalog_item_id', $catalogItemId)
+                ->sum('cantidad');
+            $this->assertUserPurchaseLimit($selectedItem, $cartQuantity + $quantity);
             $inventoryService = app(CatalogInventoryService::class);
             $availableQuantity = $inventoryService->availableQuantity($selectedItem);
 
@@ -141,6 +146,18 @@ class Cart extends Model
             );
             $inventoryService = app(CatalogInventoryService::class);
             $delta = $quantity - $item->cantidad;
+
+            if ($delta > 0) {
+                $otherVariantsQuantity = (int) $this->items()
+                    ->where('catalog_item_id', $item->catalog_item_id)
+                    ->whereKeyNot($item->getKey())
+                    ->sum('cantidad');
+                $this->assertUserPurchaseLimit(
+                    $selectedItem,
+                    $otherVariantsQuantity + $quantity,
+                );
+            }
+
             $availableQuantity = $inventoryService->availableQuantity($selectedItem);
 
             if ($delta > 0 && $availableQuantity !== null && $availableQuantity < $delta) {
@@ -256,6 +273,26 @@ class Cart extends Model
         return $variant;
     }
 
+    private function assertUserPurchaseLimit(
+        CatalogItem|Variant $selectedItem,
+        int $cartQuantity,
+    ): void {
+        if ($this->user_id === null) {
+            return;
+        }
+
+        $catalogItem = $selectedItem instanceof Variant
+            ? $selectedItem->catalogItem
+            : $selectedItem;
+
+        app(UserPurchaseLimitService::class)->assertCanPurchase(
+            $catalogItem,
+            $this->user_id,
+            $cartQuantity,
+            field: 'cantidad',
+        );
+    }
+
     protected function resolveInventory(int $inventoryId, bool $lockForUpdate): Inventory
     {
         $query = Inventory::query()->whereKey($inventoryId);