feat: enhance purchase detail handling to support cart items and improve resource structure

app/Domains/Purchase/Resources/PurchaseResource.php

@@ -2,8 +2,11 @@
 
 namespace App\Domains\Purchase\Resources;
 
+use App\Domains\Cart\Models\CartItem;
+use App\Domains\Purchase\Models\PurchaseItem;
 use Illuminate\Http\Request;
 use Illuminate\Http\Resources\Json\JsonResource;
+use Illuminate\Support\Collection;
 
 /**
  * @mixin \App\Domains\Purchase\Models\Purchase
@@ -15,20 +18,18 @@ class PurchaseResource extends JsonResource
      */
     public function toArray(Request $request): array
     {
-        $items = $this->resource->relationLoaded('items')
-            ? $this->resource->getRelation('items')
-            : collect();
+        [$items, $itemsSource] = $this->resolveItems();
 
         $subtotal = $items->isNotEmpty()
             ? $items->reduce(
-                fn (float $carry, $item): float => $carry + ((float) $item->precio_unitario * $item->cantidad),
+                fn (float $carry, PurchaseItem|CartItem $item): float => $carry + $this->resolveItemSubtotal($item),
                 0.0,
             )
             : (float) ($this->total ?? 0);
 
         $total = $items->isNotEmpty()
             ? $items->reduce(
-                fn (float $carry, $item): float => $carry + (float) $item->total,
+                fn (float $carry, PurchaseItem|CartItem $item): float => $carry + $this->resolveItemTotal($item),
                 0.0,
             )
             : (float) ($this->total ?? 0);
@@ -38,18 +39,66 @@ class PurchaseResource extends JsonResource
             'cart_id' => $this->cart_id,
             'tenant_codigo' => $this->tenant_codigo,
             'user_id' => $this->user_id,
+            'created_at' => $this->created_at,
             'status' => $this->status,
             'payment_method' => $this->payment_method,
             'dni' => $this->dni,
             'telefono' => $this->telefono,
             'nombre_apellido' => $this->nombre_apellido,
             'email' => $this->email,
+            'items_source' => $itemsSource,
             'items' => PurchaseItemResource::collection($items),
             'subtotal' => $this->formatMoney($subtotal),
             'total' => $this->formatMoney($total),
         ];
     }
 
+    /**
+     * @return array{0: Collection<int, PurchaseItem|CartItem>, 1: string|null}
+     */
+    protected function resolveItems(): array
+    {
+        if (! $this->resource->relationLoaded('items')) {
+            return [collect(), null];
+        }
+
+        $purchaseItems = $this->resource->getRelation('items');
+
+        if ($purchaseItems->isNotEmpty()) {
+            return [$purchaseItems, 'purchase'];
+        }
+
+        if (! $this->resource->relationLoaded('cart')) {
+            return [collect(), null];
+        }
+
+        $cart = $this->resource->getRelation('cart');
+
+        if ($cart === null || ! $cart->relationLoaded('items')) {
+            return [collect(), null];
+        }
+
+        return [$cart->getRelation('items'), 'cart'];
+    }
+
+    protected function resolveItemSubtotal(PurchaseItem|CartItem $item): float
+    {
+        if ($item instanceof PurchaseItem) {
+            return (float) $item->precio_unitario * $item->cantidad;
+        }
+
+        return (float) ($item->variant?->product?->precio ?? 0) * $item->cantidad;
+    }
+
+    protected function resolveItemTotal(PurchaseItem|CartItem $item): float
+    {
+        if ($item instanceof PurchaseItem) {
+            return (float) ($item->total ?? 0);
+        }
+
+        return $this->resolveItemSubtotal($item);
+    }
+
     protected function formatMoney(float|int|string|null $amount): string
     {
         return number_format((float) ($amount ?? 0), 2, '.', '');