refactor(checkout): materialize purchase item snapshots at start

app/Domains/Purchase/Services/Checkout/CompleteCheckoutService.php

@@ -15,7 +15,6 @@ class CompleteCheckoutService
     public function __construct(
         private readonly StockReservationService $reservations,
         private readonly SourceCartService $sourceCart,
-        private readonly PurchaseItemSnapshotFactory $snapshots,
         private readonly PurchaseStateGuard $purchaseState,
     ) {}
 
@@ -90,18 +89,17 @@ class CompleteCheckoutService
                 ]);
             }
 
-            if ($purchase->items()->exists()) {
-                $cart = $purchase->cart()->withTrashed()->lockForUpdate()->first();
-                if ($cart?->status === 'converted' && $cart->trashed()) {
-                    return;
-                }
-
+            if (! $purchase->items()->exists()) {
                 throw ValidationException::withMessages([
                     'items' => __('api.purchase.inconsistent_reservation'),
                 ]);
             }
 
-            $cart = $purchase->cart()->lockForUpdate()->first();
+            $cart = $purchase->cart()->withTrashed()->lockForUpdate()->first();
+            if ($cart?->status === 'converted' && $cart->trashed()) {
+                return;
+            }
+
             if ($cart === null || $cart->status !== 'checkout') {
                 throw ValidationException::withMessages([
                     'items' => __('api.purchase.inconsistent_reservation'),
@@ -115,10 +113,32 @@ class CompleteCheckoutService
                 ]);
             }
 
+            $snapshotQuantities = $purchase->items()
+                ->lockForUpdate()
+                ->get(['source_catalog_item_id', 'source_variant_id', 'cantidad'])
+                ->groupBy(fn ($item): string => $this->itemKey(
+                    (int) $item->source_catalog_item_id,
+                    $item->source_variant_id === null ? null : (int) $item->source_variant_id,
+                ))
+                ->map(fn (Collection $items): int => (int) $items->sum('cantidad'))
+                ->sortKeys()
+                ->all();
+            $cartQuantities = $cartItems
+                ->groupBy(fn (CartItem $item): string => $this->itemKey(
+                    (int) $item->catalog_item_id,
+                    $item->variant_id === null ? null : (int) $item->variant_id,
+                ))
+                ->map(fn (Collection $items): int => (int) $items->sum('cantidad'))
+                ->sortKeys()
+                ->all();
+
+            if ($snapshotQuantities !== $cartQuantities) {
+                throw ValidationException::withMessages([
+                    'items' => __('api.purchase.inconsistent_reservation'),
+                ]);
+            }
+
             $this->loadCartItems($cartItems);
-            $purchase->items()->createMany(
-                $this->snapshots->fromCartItems($cartItems),
-            );
 
             foreach ($cartItems as $cartItem) {
                 $selection = $cartItem->selectedItem();
@@ -159,16 +179,12 @@ class CompleteCheckoutService
 
     private function loadPurchase(Purchase $purchase): Purchase
     {
-        return $purchase->load([
-            'items.imageAttachment',
-            'cart.items.catalogItem.inventory',
-            'cart.items.catalogItem.attachments',
-            'cart.items.variant.inventory',
-            'cart.items.variant.attachments',
-            'cart.items.variant.definitions.itemAttribute.attribute',
-            'cart.items.variant.eventDates',
-            'cart.items.variant.eventDate',
-        ]);
+        return $purchase->load(['items.imageAttachment']);
+    }
+
+    private function itemKey(int $catalogItemId, ?int $variantId): string
+    {
+        return $catalogItemId.':'.($variantId ?? 'none');
     }
 
     /** @param Collection<int, CartItem> $cartItems */

app/Domains/Purchase/Services/Checkout/PurchaseResponseLoader.php

@@ -8,51 +8,6 @@ class PurchaseResponseLoader
 {
     public function load(Purchase $purchase): Purchase
     {
-        $purchase->load(['tenant', 'items.imageAttachment']);
-
-        if (
-            $purchase->cart_id !== null
-            && (
-                in_array($purchase->status, [
-                    Purchase::STATUS_CREATED,
-                    Purchase::STATUS_PENDING_PAYMENT,
-                ], true)
-                || $purchase->items->isEmpty()
-            )
-        ) {
-            $purchase->load([
-                'cart.items.catalogItem.inventory',
-                'cart.items.catalogItem.attachments',
-                'cart.items.variant.inventory',
-                'cart.items.variant.attachments',
-                'cart.items.variant.catalogItem',
-                'cart.items.variant.definitions.itemAttribute.attribute',
-                'cart.items.variant.eventDates',
-                'cart.items.variant.eventDate',
-            ]);
-        }
-
-        if (! $purchase->tenant->checkout_editing_policy->allowsVariantChanges()) {
-            return $purchase;
-        }
-
-        $purchase->load([
-            'items.sourceCatalogItem.itemAttributes.attribute',
-            'items.sourceCatalogItem.variants' => fn ($query) => $query->orderBy('id'),
-            'items.sourceCatalogItem.variants.inventory',
-            'items.sourceCatalogItem.variants.definitions' => fn ($query) => $query->orderBy('id'),
-            'items.sourceCatalogItem.variants.definitions.itemAttribute.attribute.options',
-            'items.sourceCatalogItem.variants.eventDates',
-            'items.sourceCatalogItem.variants.eventDate',
-            'cart.items.catalogItem.itemAttributes.attribute',
-            'cart.items.catalogItem.variants' => fn ($query) => $query->orderBy('id'),
-            'cart.items.catalogItem.variants.inventory',
-            'cart.items.catalogItem.variants.definitions' => fn ($query) => $query->orderBy('id'),
-            'cart.items.catalogItem.variants.definitions.itemAttribute.attribute.options',
-            'cart.items.catalogItem.variants.eventDates',
-            'cart.items.catalogItem.variants.eventDate',
-        ]);
-
-        return $purchase;
+        return $purchase->load(['tenant', 'items.imageAttachment']);
     }
 }

app/Domains/Purchase/Services/Checkout/ReleaseCheckoutService.php

@@ -96,12 +96,6 @@ class ReleaseCheckoutService
                 return $this->loadPurchase($purchase);
             }
 
-            if ($purchase->items()->exists()) {
-                throw ValidationException::withMessages([
-                    'items' => __('api.purchase.inconsistent_reservation'),
-                ]);
-            }
-
             $reservationReturnedToCart = $restoreCart && $this->sourceCart->restore($purchase);
             $this->releaseCartReservations($purchase, $reservationReturnedToCart, $targetStatus);
 
@@ -181,15 +175,6 @@ class ReleaseCheckoutService
 
     private function loadPurchase(Purchase $purchase): Purchase
     {
-        return $purchase->load([
-            'items.imageAttachment',
-            'cart.items.catalogItem.inventory',
-            'cart.items.catalogItem.attachments',
-            'cart.items.variant.inventory',
-            'cart.items.variant.attachments',
-            'cart.items.variant.definitions.itemAttribute.attribute',
-            'cart.items.variant.eventDates',
-            'cart.items.variant.eventDate',
-        ]);
+        return $purchase->load(['items.imageAttachment']);
     }
 }

app/Domains/Purchase/Services/Checkout/StartCheckoutService.php

@@ -26,6 +26,7 @@ class StartCheckoutService
         private readonly CatalogSelectionResolver $selections,
         private readonly InsufficientStockMessageBuilder $stockMessages,
         private readonly PurchaseResponseLoader $responses,
+        private readonly PurchaseItemSnapshotFactory $snapshots,
     ) {}
 
     /** @param array<string, mixed> $purchaseData */
@@ -193,6 +194,10 @@ class StartCheckoutService
             $cart->getKey(),
         );
 
+        $cartItems = $cart->items()->orderBy('id')->lockForUpdate()->get();
+        $this->loadCartItems($cartItems);
+        $purchase->items()->createMany($this->snapshots->fromCartItems($cartItems));
+
         foreach ($cartItems as $index => $cartItem) {
             $this->reservations->attachToPurchase(
                 $cartItem,
@@ -259,6 +264,8 @@ class StartCheckoutService
             $cart->getTotalAmount(),
             $cart->getKey(),
         );
+        $purchase->items()->createMany($this->snapshots->fromCartItems($cartItems));
+
         foreach ($cartItems as $cartItem) {
             $this->reservations->attachToPurchase(
                 $cartItem,