feat: Implement inventory policy for product variants

- Introduced InventoryPolicy enum to manage tracked and unlimited inventory types.
- Updated ProductVariant model to include inventory_policy and cantidad_vendida attributes.
- Modified addItem and updateItem methods in Cart to check available quantity based on inventory policy.
- Added migration to include inventory_policy and cantidad_vendida in productos_variantes table.
- Enhanced tests to validate inventory behavior for both tracked and unlimited policies.
- Updated various request and resource classes to handle new inventory fields.

app/Domains/Catalog/Models/ProductVariant.php

@@ -3,17 +3,18 @@
 namespace App\Domains\Catalog\Models;
 
 use App\Domains\Attachable\Models\Attachment;
+use App\Domains\Catalog\Enums\InventoryPolicy;
 use Illuminate\Database\Eloquent\Attributes\Fillable;
+use Illuminate\Database\Eloquent\Casts\Attribute;
 use Illuminate\Database\Eloquent\Factories\HasFactory;
 use Illuminate\Database\Eloquent\Model;
 use Illuminate\Database\Eloquent\Relations\BelongsTo;
 use Illuminate\Database\Eloquent\Relations\BelongsToMany;
 use Illuminate\Database\Eloquent\Relations\HasMany;
 
-use Illuminate\Database\Eloquent\Casts\Attribute;
-
 #[Fillable([
     'producto_id',
+    'inventory_policy',
     'stock_real',
     'stock_reservado',
     'stock',
@@ -30,9 +31,20 @@ class ProductVariant extends Model
 
     protected $appends = ['stock_tecnico'];
 
+    protected $attributes = [
+        'inventory_policy' => 'tracked',
+        'stock_real' => 0,
+        'stock_reservado' => 0,
+        'cantidad_vendida' => 0,
+    ];
+
     protected static function booted(): void
     {
         static::saving(function (ProductVariant $variant) {
+            if ($variant->exists && $variant->isDirty('inventory_policy')) {
+                throw new \InvalidArgumentException('La politica de inventario no puede modificarse.');
+            }
+
             $variant->validateStock();
         });
     }
@@ -47,34 +59,44 @@ class ProductVariant extends Model
             throw new \InvalidArgumentException('El stock reservado no puede ser negativo.');
         }
 
-        if ($this->stock_reservado > $this->stock_real) {
+        if ($this->cantidad_vendida < 0) {
+            throw new \InvalidArgumentException('La cantidad vendida no puede ser negativa.');
+        }
+
+        if ($this->tracksInventory() && $this->stock_reservado > $this->stock_real) {
             throw new \InvalidArgumentException('El stock reservado no puede ser mayor que el stock real.');
         }
     }
 
-    public function incrementRealStock(int $amount): void
+    public function tracksInventory(): bool
+    {
+        return $this->inventory_policy === InventoryPolicy::Tracked;
+    }
+
+    public function availableQuantity(): ?int
+    {
+        if (! $this->tracksInventory()) {
+            return null;
+        }
+
+        return $this->stock_real - $this->stock_reservado;
+    }
+
+    public function isAvailableForSale(): bool
+    {
+        return ! $this->tracksInventory() || $this->availableQuantity() > 0;
+    }
+
+    public function reserveStock(int $amount): void
     {
         if ($amount < 0) {
             throw new \InvalidArgumentException('El monto a incrementar debe ser positivo.');
         }
-        $this->stock_real += $amount;
-        $this->save();
-    }
 
-    public function decrementRealStock(int $amount): void
-    {
-        if ($amount < 0) {
-            throw new \InvalidArgumentException('El monto a decrementar debe ser positivo.');
+        if ($this->tracksInventory() && $this->availableQuantity() < $amount) {
+            throw new \InvalidArgumentException('No hay suficiente stock disponible para reservar.');
         }
-        $this->stock_real -= $amount;
-        $this->save();
-    }
 
-    public function incrementReservedStock(int $amount): void
-    {
-        if ($amount < 0) {
-            throw new \InvalidArgumentException('El monto a incrementar debe ser positivo.');
-        }
         $this->stock_reservado += $amount;
         $this->save();
     }
@@ -88,13 +110,13 @@ class ProductVariant extends Model
         $this->save();
     }
 
-    public function confirmReservedStock(int $amount): void
+    public function buy(int $amount): void
     {
         if ($amount < 0) {
             throw new \InvalidArgumentException('El monto a confirmar debe ser positivo.');
         }
 
-        if ($this->stock_real < $amount) {
+        if ($this->tracksInventory() && $this->stock_real < $amount) {
             throw new \InvalidArgumentException('No hay suficiente stock real para confirmar la reserva.');
         }
 
@@ -102,14 +124,18 @@ class ProductVariant extends Model
             throw new \InvalidArgumentException('No hay suficiente stock reservado para confirmar la reserva.');
         }
 
-        $this->stock_real -= $amount;
+        if ($this->tracksInventory()) {
+            $this->stock_real -= $amount;
+        }
+
         $this->stock_reservado -= $amount;
+        $this->cantidad_vendida += $amount;
         $this->save();
     }
 
     protected function stockTecnico(): Attribute
     {
-        return Attribute::get(fn () => $this->stock_real - $this->stock_reservado);
+        return Attribute::get(fn (): ?int => $this->availableQuantity());
     }
 
     protected function stock(): Attribute
@@ -126,8 +152,10 @@ class ProductVariant extends Model
     {
         return [
             'producto_id' => 'integer',
+            'inventory_policy' => InventoryPolicy::class,
             'stock_real' => 'integer',
             'stock_reservado' => 'integer',
+            'cantidad_vendida' => 'integer',
             'is_placeholder' => 'boolean',
             'has_tickets' => 'boolean',
             'minimum_use_date' => 'datetime',