finish payment logic

backend/order/models.py

@@ -55,6 +55,11 @@ class Cart(models.Model):
     def __str__(self):
         return f"Cart for {self.user.email}"
 
+    def clear_cart(self):
+        self.items.all().delete()
+        self.discount_code = None
+        self.save()
+
     @property
     def discount_code_amount(self):
         if self.discount_code:
@@ -151,6 +156,11 @@ class OrderModel(models.Model):
     cart_total = models.BigIntegerField(
         null=True, blank=True, verbose_name='کل سبد خرید')
 
+    cart = models.ForeignKey(Cart, on_delete=models.CASCADE, null=True, blank=True)
+    
+    is_stock_rolled_back = models.BooleanField(
+        default=False, verbose_name="موجودی برگردانده شده")
+
     def __str__(self):
         return f'سفارش: {self.pk + 1000}'
 
@@ -158,6 +168,34 @@ class OrderModel(models.Model):
         verbose_name = 'سفارش'
         verbose_name_plural = 'سفارشات'
 
+    def rollback_stock(self):
+            """
+            Rollback stock quantities for all items in this order
+            Returns True if successful, False otherwise
+            """
+            if self.is_stock_rolled_back:
+                return False
+            
+            # if not self.cart:
+            #     return False
+            
+            try:
+                # Get all cart items and rollback their stock
+                for order_item in self.items.all():
+                    product = order_item.product
+                    # Add back the quantity to stock
+                    product.stock_quantity += order_item.quantity
+                    product.save()
+                
+                # Mark as rolled back
+                self.is_stock_rolled_back = True
+                self.save(update_fields=['is_stock_rolled_back'])
+                return True
+                
+            except Exception as e:
+                # Log the error if you have logging setup
+                # logger.error(f"Failed to rollback stock for order {self.pk}: {e}")
+                return False
 
 class OrderItemModel(models.Model):
     order = models.ForeignKey(