allow modification and removal of cart or order items

git-svn-id: svn://svn.cy55.de/Zope3/src/cybertools/trunk@3275 fd906abe-77d9-0310-91a1-e0d9ade77398

commerce/README.txt

@@ -88,6 +88,27 @@ A cart is just a collection of order items belonging to a certain customer
 
   >>> orderItems.getCart(c001)
   [<OrderItem [2, 1, 7, '... ...', '???']: {'shop': 0, 'quantity': 3}>]
+  >>> item1 = orderItems.getCart(c001, shop=shop1, product=p001)[0]
+  >>> item1
+  <OrderItem [2, 1, 7, '... ...', '???']: {'shop': 0, 'quantity': 3}>
+
+  >>> orderItems.add(p003, c001, shop=shop1, quantity=1)
+  <OrderItem [4, 2, 7, '... ...', '???']: {'shop': 0, 'quantity': 1}>
+
+  >>> len(orderItems.getCart(c001))
+  2
+
+If we add the same product again to the cart no new item is created but
+the quantity is added to the existing item.
+
+  >>> orderItems.add(p003, c001, shop=shop1, quantity=1)
+  <OrderItem [4, 2, 7, '... ...', '???']: {'shop': 0, 'quantity': 2}>
+  >>> len(orderItems.getCart(c001))
+  2
+
+  >>> item1.remove()
+  >>> len(orderItems.getCart(c001))
+  1
 
 Orders
 ------
@@ -105,4 +126,4 @@ retrieving the order items.
   >>> orderItems.getCart(c001)
   []
   >>> orderItems.getCart(c001, ord001)
-  [<OrderItem [2, 1, 7, '... ...', 11]: {'shop': 0, 'quantity': 3}>]
+  [<OrderItem [4, 2, 7, '... ...', 11]: {'shop': 0, 'quantity': 2}>]

commerce/interfaces.py

@@ -345,6 +345,15 @@ class IOrderItem(ITrack):
                     u'items ordered.')
     fullPrice = Attribute(u'The full price for the quantity ordered.')
 
+    def remove():
+        """ Remove the order item from the order or cart.
+        """
+
+    def modify(quantity, **kw):
+        """ Change the quantity of the order item (and optionally other
+            attributes).
+        """
+
     def setOrder(order):
         """ Assign the order given to the order item.
         """
@@ -367,9 +376,12 @@ class IOrderItems(Interface):
             product, party, order, run, timeFrom, timeTo.
         """
 
-    def add(product, party, shop, order='???', run=0, **kw):
+    def add(product, party, shop, order='???', run=0, quantity=1, **kw):
         """ Create and register an order item; return it. Additional properties
             may be specified via keyword arguments.
+
+            If the order item is already present do not create a new one
+            but add the quantity.
         """
 
     def getCart(party=None, order='???', shop=None, run=0, **kw):

commerce/order.py

@@ -74,6 +74,13 @@ class OrderItem(Track):
                 return (tp, id)
         return ref
 
+    def remove(self):
+        self.getParent().context.removeTrack(self)
+
+    def modify(self, quantity, **kw):
+        self.data['quantity'] = quantity
+        return self
+
     def setOrder(self, order):
         parent = self.getParent()
         self.order = parent.getUid(order)
@@ -109,11 +116,16 @@ class OrderItems(object):
 
     def add(self, product, party, shop, order='???', run=0, **kw):
         kw['shop'] = self.getUid(shop)
-        trackId = self.context.saveUserTrack(self.getUid(product), run,
-                            self.getUid(party), kw)
-        track = self[trackId]
-        track.order = self.getUid(order)
-        self.context.indexTrack(0, track, 'order')
+        existing = self.getCart(party, order, shop, run, product=product)
+        if existing:
+            track = existing[-1]
+            track.modify(track.quantity + kw.get('quantity', 1))
+        else:
+            trackId = self.context.saveUserTrack(self.getUid(product), run,
+                                self.getUid(party), kw)
+            track = self[trackId]
+            track.order = self.getUid(order)
+            self.context.indexTrack(0, track, 'order')
         return track
 
     def getCart(self, party=None, order='???', shop=None, run=None, **kw):
@@ -122,6 +134,7 @@ class OrderItems(object):
         result = self.query(party=party, order=order, **kw)
         if shop is None:
             return list(result)
+        shop = self.getUid(shop)
         return [item for item in result if item.shop == shop]
 
     # utility methods