added functions to Order model

orders/models.py

@@ -1,4 +1,5 @@
-from django.db import models
+from django.db import models, connection
+from django.db.models import Count, Q
 
 
 class Order(models.Model):
@@ -10,6 +11,45 @@ class Order(models.Model):
     )
     shipping_method = models.CharField(max_length=100, choices=SHIPPING_CHOICES)
     date_completed = models.DateTimeField()
+
+    @classmethod
+    def split_by_shipping_method(cls):
+        """ Return two lists of primary keys: one for orders done by First Class Mail, and one for
+        orders done by Priority Mail."""
+        fcm = list(cls.objects.filter(shipping_method='FCM').values_list('pk', flat=True))
+        pri = list(cls.objects.filter(shipping_method='PRI').values_list('pk', flat=True))
+        return fcm, pri
+
+    @classmethod
+    def split_by_single_and_multiple(cls):
+        """ Return two lists of primary keys: one for orders that have only one item, and one for
+        orders that have multiple items."""
+        singles = list(cls.objects.annotate(Count('items')).filter(items__count=1).values_list('pk', flat=True))
+        multiples = list(cls.objects.annotate(Count('items')).filter(items__count__gte=2).values_list('pk', flat=True))
+        return singles, multiples
+
+    @classmethod
+    def single_orders_are_sorted(cls):
+        """ Return list of orders with only one item, sorted by the priority denoted in the priority attribute of the OrderItem
+        class (XS -> XXL)."""
+        cursor = connection.cursor()
+        cursor.execute("""SELECT innerQuery.id, orders_orderitem.product from (SELECT orders_order.id FROM orders_order LEFT OUTER JOIN orders_orderitem ON ( orders_order.id = orders_orderitem.order_id ) 
+        GROUP BY orders_order.id, orders_order.shipping_method, orders_order.date_completed
+        HAVING COUNT(orders_orderitem.id) = 1) innerQuery LEFT OUTER JOIN orders_orderitem ON (innerQuery.id = orders_orderitem.order_id)""")
+
+        single_orders = cursor.fetchall()
+        single_sorted_orders = [pk for (pk, product) in sorted(single_orders, key=lambda tup: OrderItem.priority[tup[1]])]
+        return single_sorted_orders
+
+    @classmethod
+    def orders_split_by_xxl_and_not(cls):
+        """ Return two lists of primary keys: one for multiple orders that include at least one 
+        XXL shirt, and one for multiple orders that have no XXL shirts."""
+        base_query = cls.objects.annotate(Count('items')).filter(items__count__gte=2)
+        xxl = list(base_query.filter(items__product='XXL').values_list('pk', flat=True))
+        not_xxl = list(base_query.filter(~Q(items__product = 'XXL')).values_list('pk', flat=True))
+        return xxl, not_xxl
+
 
 
 class OrderItem(models.Model):

orders/tests.py

@@ -9,20 +9,20 @@ class OrderOrderingTestCase(TestCase):
     fixtures = ['test_orders.json']
 
     def test_orders_are_split_by_shipping_method(self):
-        #fcm, pri = Order.split_by_shipping_method()
+        fcm, pri = Order.split_by_shipping_method()
         self.assertEqual(results.fcm, fcm)
         self.assertEqual(results.pri, pri)
 
     def test_orders_are_split_by_single_and_multiple(self):
-        #singles, multiples = Order.split_by_single_and_multiple()
+        singles, multiples = Order.split_by_single_and_multiple()
         self.assertEqual(results.singles, singles)
         self.assertEqual(results.multiples, multiples)
 
     def test_single_orders_are_sorted(self):
-        #single_sorted_orders = Order.single_orders_are_sorted()
+        single_sorted_orders = Order.single_orders_are_sorted()
         self.assertEqual(results.single_sorted_orders, single_sorted_orders)
 
     def test_multiple_orders_are_split_by_xxl_and_not(self):
-        #xxl, not_xxl = Order.orders_split_by_xxl_and_not()
+        xxl, not_xxl = Order.orders_split_by_xxl_and_not()
         self.assertEqual(results.xxl, xxl)
         self.assertEqual(results.not_xxl, not_xxl)