feat: implement multi-tenant cart system with stock reservation and inventory tracking

app/Domains/Catalog/Models/ProductVariant.php

@@ -10,8 +10,12 @@ 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',
+    'stock_real',
+    'stock_reservado',
     'stock',
     'is_placeholder',
 ])]
@@ -21,11 +25,87 @@ class ProductVariant extends Model
 
     protected $table = 'productos_variantes';
 
+    protected $appends = ['stock_tecnico'];
+
+    protected static function booted(): void
+    {
+        static::saving(function (ProductVariant $variant) {
+            $variant->validateStock();
+        });
+    }
+
+    public function validateStock(): void
+    {
+        if ($this->stock_real < 0) {
+            throw new \InvalidArgumentException('El stock real no puede ser negativo.');
+        }
+
+        if ($this->stock_reservado < 0) {
+            throw new \InvalidArgumentException('El stock reservado no puede ser negativo.');
+        }
+
+        if ($this->stock_reservado > $this->stock_real) {
+            throw new \InvalidArgumentException('El stock reservado no puede ser mayor que el stock real.');
+        }
+    }
+
+    public function incrementRealStock(int $amount): void
+    {
+        if ($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.');
+        }
+        $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();
+    }
+
+    public function decrementReservedStock(int $amount): void
+    {
+        if ($amount < 0) {
+            throw new \InvalidArgumentException('El monto a decrementar debe ser positivo.');
+        }
+        $this->stock_reservado -= $amount;
+        $this->save();
+    }
+
+    protected function stockTecnico(): Attribute
+    {
+        return Attribute::get(fn () => $this->stock_real - $this->stock_reservado);
+    }
+
+    protected function stock(): Attribute
+    {
+        return Attribute::make(
+            get: fn () => $this->stock_real,
+            set: fn ($value) => [
+                'stock_real' => $value,
+            ]
+        );
+    }
+
     protected function casts(): array
     {
         return [
             'producto_id' => 'integer',
-            'stock' => 'integer',
+            'stock_real' => 'integer',
+            'stock_reservado' => 'integer',
             'is_placeholder' => 'boolean',
         ];
     }