feat(cart): enhance item update functionality to support variant changes and stock management; update related request validation and resource formatting; add tests for variant handling in cart

app/Domains/Cart/Controllers/CartController.php

@@ -54,16 +54,26 @@ class CartController extends Controller
         Tenant $tenant,
         CartItem $cartItem,
     ): CartResource {
+        $updatesVariant = $request->exists('variant_id');
+
         return CartResource::make(
-            $this->cartService->updateItemQuantity(
+            $this->cartService->updateItem(
                 $tenant,
                 $request,
                 $cartItem->getKey(),
                 (int) $request->validated('cantidad'),
+                $updatesVariant
+                    ? ($request->validated('variant_id') !== null
+                        ? (int) $request->validated('variant_id')
+                        : null)
+                    : $cartItem->variant_id,
+                $updatesVariant,
             )
         )->additional([
-            'code' => 'cart.quantity_updated',
-            'message' => __('api.cart.quantity_updated'),
+            'code' => $updatesVariant ? 'cart.item_updated' : 'cart.quantity_updated',
+            'message' => $updatesVariant
+                ? __('api.cart.item_updated')
+                : __('api.cart.quantity_updated'),
         ]);
     }
 

app/Domains/Cart/Models/Cart.php

@@ -124,27 +124,85 @@ class Cart extends Model
         });
     }
 
-    public function updateItem(int $cartItemId, int $quantity): CartItem
-    {
+    public function updateItem(
+        int $cartItemId,
+        int $quantity,
+        ?int $variantId = null,
+        bool $updateVariant = false,
+    ): CartItem {
         if ($quantity <= 0) {
             throw ValidationException::withMessages([
                 'cantidad' => __('api.cart.positive_quantity'),
             ]);
         }
 
-        return DB::transaction(function () use ($cartItemId, $quantity): CartItem {
+        return DB::transaction(function () use (
+            $cartItemId,
+            $quantity,
+            $variantId,
+            $updateVariant,
+        ): CartItem {
             /** @var CartItem $item */
             $item = $this->items()
                 ->where('id', $cartItemId)
                 ->lockForUpdate()
                 ->firstOrFail();
 
-            $selectedItem = $this->resolveScopedItem(
+            $currentSelection = $this->resolveScopedItem(
                 $item->catalog_item_id,
                 $item->variant_id,
                 true,
             );
             $inventoryService = app(CatalogInventoryService::class);
+
+            if ($updateVariant && $variantId !== $item->variant_id) {
+                $nextSelection = $this->resolveScopedItem(
+                    $item->catalog_item_id,
+                    $variantId,
+                    true,
+                );
+                $otherVariantsQuantity = (int) $this->items()
+                    ->where('catalog_item_id', $item->catalog_item_id)
+                    ->whereKeyNot($item->getKey())
+                    ->sum('cantidad');
+                $this->assertUserPurchaseLimit(
+                    $nextSelection,
+                    $otherVariantsQuantity + $quantity,
+                );
+
+                $inventoryService->release($currentSelection, $item->cantidad);
+                $availableQuantity = $inventoryService->availableQuantity($nextSelection);
+
+                if ($availableQuantity !== null && $availableQuantity < $quantity) {
+                    throw ValidationException::withMessages([
+                        'variant_id' => __('api.cart.insufficient_stock', ['max' => $availableQuantity]),
+                    ]);
+                }
+
+                $targetItem = $this->items()
+                    ->where('catalog_item_id', $item->catalog_item_id)
+                    ->where('variant_id', $variantId)
+                    ->whereKeyNot($item->getKey())
+                    ->lockForUpdate()
+                    ->first();
+
+                $inventoryService->reserve($nextSelection, $quantity);
+
+                if ($targetItem !== null) {
+                    $targetItem->cantidad += $quantity;
+                    $targetItem->save();
+                    $item->delete();
+
+                    return $targetItem->fresh();
+                }
+
+                $item->variant_id = $variantId;
+                $item->cantidad = $quantity;
+                $item->save();
+
+                return $item->fresh();
+            }
+
             $delta = $quantity - $item->cantidad;
 
             if ($delta > 0) {
@@ -153,12 +211,12 @@ class Cart extends Model
                     ->whereKeyNot($item->getKey())
                     ->sum('cantidad');
                 $this->assertUserPurchaseLimit(
-                    $selectedItem,
+                    $currentSelection,
                     $otherVariantsQuantity + $quantity,
                 );
             }
 
-            $availableQuantity = $inventoryService->availableQuantity($selectedItem);
+            $availableQuantity = $inventoryService->availableQuantity($currentSelection);
 
             if ($delta > 0 && $availableQuantity !== null && $availableQuantity < $delta) {
                 $maxAvailable = $availableQuantity + $item->cantidad;
@@ -171,11 +229,11 @@ class Cart extends Model
             $item->save();
 
             if ($delta > 0) {
-                $inventoryService->reserve($selectedItem, $delta);
+                $inventoryService->reserve($currentSelection, $delta);
             }
 
             if ($delta < 0) {
-                $inventoryService->release($selectedItem, abs($delta));
+                $inventoryService->release($currentSelection, abs($delta));
             }
 
             return $item->fresh();

app/Domains/Cart/Requests/UpdateCartItemQuantityRequest.php

@@ -19,7 +19,7 @@ class UpdateCartItemQuantityRequest extends FormRequest
         return [
             'cantidad' => ['required', 'integer', 'min:1'],
             'catalog_item_id' => ['prohibited'],
-            'variant_id' => ['prohibited'],
+            'variant_id' => ['sometimes', 'nullable', 'integer'],
         ];
     }
 }

app/Domains/Cart/Resources/CartItemResource.php

@@ -3,8 +3,11 @@
 namespace App\Domains\Cart\Resources;
 
 use App\Domains\Cart\Models\CartItem;
+use App\Domains\Catalog\Enums\InventoryPolicy;
+use App\Domains\Catalog\Models\Variant;
 use Illuminate\Http\Request;
 use Illuminate\Http\Resources\Json\JsonResource;
+use Illuminate\Support\Collection;
 
 /**
  * @mixin CartItem
@@ -36,10 +39,42 @@ class CartItemResource extends JsonResource
             'product' => $selectedItem === null ? null : [
                 'nombre' => $selectedItem->getName(),
                 'imagen' => $imageUrl,
+                'variants' => $this->catalogItem->variants
+                    ->map(fn (Variant $variant): array => [
+                        'id' => $variant->id,
+                        'precio' => $this->formatMoney($variant->getPrice()),
+                        'stock_tecnico' => $this->catalogItem->inventory_policy === InventoryPolicy::Unlimited
+                            ? null
+                            : $variant->inventory->availableStock(),
+                        'values' => $this->variantValues($variant),
+                    ])
+                    ->values(),
             ],
         ];
     }
 
+    /** @return Collection<string, string|array<int, string>> */
+    private function variantValues(Variant $variant): Collection
+    {
+        $values = $variant->selectionValues();
+        $eventDates = $variant->selectedEventDates();
+
+        if ($eventDates->isNotEmpty()) {
+            $labels = $eventDates
+                ->map(fn ($eventDate): string => $eventDate->date->format('d/m/Y').' · '
+                    .substr($eventDate->time_start, 0, 5).' a '
+                    .substr($eventDate->time_end, 0, 5))
+                ->values();
+
+            $values->put(
+                'event_date',
+                $labels->count() === 1 ? $labels->first() : $labels->all(),
+            );
+        }
+
+        return $values;
+    }
+
     protected function formatMoney(float|int|string|null $amount): string
     {
         return number_format((float) ($amount ?? 0), 2, '.', '');

app/Domains/Cart/Services/CartService.php

@@ -51,11 +51,17 @@ class CartService
         ];
     }
 
-    public function updateItemQuantity(Tenant $tenant, Request $request, int $cartItemId, int $quantity): Cart
-    {
+    public function updateItem(
+        Tenant $tenant,
+        Request $request,
+        int $cartItemId,
+        int $quantity,
+        ?int $variantId,
+        bool $updateVariant,
+    ): Cart {
         $identity = $this->requireIdentity($request);
         $cart = $this->findCartOrFail($tenant, $identity);
-        $cart->updateItem($cartItemId, $quantity);
+        $cart->updateItem($cartItemId, $quantity, $variantId, $updateVariant);
 
         return $this->loadCart($cart);
     }
@@ -101,6 +107,10 @@ class CartService
         return $cart->fresh()->load([
             'items.catalogItem.attachments',
             'items.catalogItem.inventory',
+            'items.catalogItem.variants.inventory',
+            'items.catalogItem.variants.definitions.itemAttribute.attribute',
+            'items.catalogItem.variants.eventDates',
+            'items.catalogItem.variants.eventDate',
             'items.variant.attachments',
             'items.variant.inventory',
             'items.variant.definitions.itemAttribute.attribute',