feat(catalog): implement maximum addable quantity logic and user quota sharing across variants

app/Domains/Catalog/Resources/CatalogSearchItemResource.php

@@ -5,6 +5,7 @@ namespace App\Domains\Catalog\Resources;
 use App\Domains\Catalog\Enums\InventoryPolicy;
 use App\Domains\Catalog\Models\CatalogItem;
 use App\Domains\Catalog\Models\Variant;
+use App\Domains\Catalog\Services\CatalogItemAllowanceService;
 use Illuminate\Http\Request;
 use Illuminate\Http\Resources\Json\JsonResource;
 
@@ -27,6 +28,7 @@ class CatalogSearchItemResource extends JsonResource
             'precio' => $this->precio,
             'image' => $attachment?->getTemporaryUrl(1440),
             'stock_tecnico' => $this->availableStock(),
+            'maximum_addable_quantity' => $this->maximumAddable($this->availableStock()),
             'variants' => $this->visibleVariants()
                 ->map(fn (Variant $variant): array => [
                     'id' => $variant->id,
@@ -39,9 +41,22 @@ class CatalogSearchItemResource extends JsonResource
                     'stock_tecnico' => $this->inventory_policy === InventoryPolicy::Unlimited
                         ? null
                         : $variant->inventory?->availableStock(),
+                    'maximum_addable_quantity' => $this->maximumAddable(
+                        $this->inventory_policy === InventoryPolicy::Unlimited
+                            ? null
+                            : $variant->inventory?->availableStock(),
+                    ),
                     'values' => $variant->selectorOptions($this->itemAttributes),
                 ])
                 ->values(),
         ];
     }
+
+    private function maximumAddable(?int $stock): ?int
+    {
+        return app(CatalogItemAllowanceService::class)->maximumAddableQuantity(
+            $stock,
+            $this->getAttribute('remaining_user_quota'),
+        );
+    }
 }