Allow to cancel order when deleting last line

saleor/dashboard/order/forms.py

@@ -128,34 +128,12 @@ def __init__(self, *args, **kwargs):
         self.item = kwargs.pop('item')
         super(CancelItemsForm, self).__init__(*args, **kwargs)
 
-    def clean(self):
-        data = super(CancelItemsForm, self).clean()
-        # Check if this line is not the only line in this order
-        order = self.item.delivery_group.order
-        other_group_items = self.item.delivery_group.items.exclude(
-            pk=self.item.pk)
-        other_groups = order.groups.exclude(pk=self.item.delivery_group.pk)
-        if not other_group_items and not other_groups:
-            # There is only one group in this order and user wants
-            # to cancel this one line
-            # He should cancel whole order instead.
-            raise forms.ValidationError(
-                _('This is the only line in Order. '
-                  'You should cancel whole order instead.'))
-        return data
-
     def cancel_item(self):
-        delivery_group = self.item.delivery_group
-        Stock.objects.deallocate_stock(self.item.stock, self.item.quantity)
-        self.item.delete()
-        delivery_group = DeliveryGroup.objects.get(pk=delivery_group.pk)
-        order = delivery_group.order
-        if not delivery_group.items.exists():
-            # Should we cancel order after dropping this group?
-            if order.groups.exclude(pk=delivery_group.pk).exists():
-                # we have another delivery groups as well
-                delivery_group.delete()
-                Order.objects.recalculate_order(order)
+        if self.item.stock:
+            Stock.objects.deallocate_stock(self.item.stock, self.item.quantity)
+        order = self.item.delivery_group.order
+        OrderedItem.objects.remove_empty_groups(self.item, force=True)
+        Order.objects.recalculate_order(order)
 
 
 class ChangeQuantityForm(forms.ModelForm):
@@ -227,7 +205,8 @@ def __init__(self, *args, **kwargs):
 
     def cancel_group(self):
         for line in self.delivery_group:
-            Stock.objects.deallocate_stock(line.stock, line.quantity)
+            if line.stock:
+                Stock.objects.deallocate_stock(line.stock, line.quantity)
         self.delivery_group.status = Status.CANCELLED
         self.delivery_group.save()
         other_groups = self.delivery_group.order.groups.all()

saleor/order/models.py

@@ -33,7 +33,10 @@ def recalculate_order(self, order):
         total_net = sum(p.net for p in prices)
         total_gross = sum(p.gross for p in prices)
         shipping = [group.shipping_price for group in order]
-        total_shipping = sum(shipping[1:], shipping[0])
+        if shipping:
+            total_shipping = sum(shipping[1:], shipping[0])
+        else:
+            total_shipping = Price(0, currency=settings.DEFAULT_CURRENCY)
         total = Price(net=total_net, gross=total_gross,
                       currency=settings.DEFAULT_CURRENCY)
         total += total_shipping
@@ -180,11 +183,15 @@ def total(self, price):
         self.total_tax = Price(price.tax, currency=price.currency)
 
     def get_subtotal_without_voucher(self):
-        return super(Order, self).get_total()
+        if self.get_items():
+            return super(Order, self).get_total()
+        return Price(net=0, currency=settings.DEFAULT_CURRENCY)
 
     def get_total_shipping(self):
         costs = [group.shipping_price for group in self]
-        return sum(costs[1:], costs[0])
+        if costs:
+            return sum(costs[1:], costs[0])
+        return Price(net=0, currency=settings.DEFAULT_CURRENCY)
 
     def can_cancel(self):
         return self.status not in {Status.CANCELLED, Status.SHIPPED}
@@ -263,8 +270,6 @@ def can_cancel(self):
 class OrderedItemManager(models.Manager):
 
     def move_to_group(self, item, target_group, quantity):
-        source_group = item.delivery_group
-        order = target_group.order
         try:
             target_item = target_group.items.get(
                 product=item.product, product_name=item.product_name,
@@ -280,11 +285,16 @@ def move_to_group(self, item, target_group, quantity):
             target_item.quantity += quantity
             target_item.save()
         item.quantity -= quantity
+        self.remove_empty_groups(item)
+
+    def remove_empty_groups(self, item, force=False):
+        source_group = item.delivery_group
+        order = source_group.order
         if item.quantity:
             item.save()
         else:
             item.delete()
-        if not source_group.get_total_quantity():
+        if not source_group.get_total_quantity() or force:
             source_group.delete()
         if not order.get_items():
             order.change_status('cancelled')