From faa25c9b3a7db39e148fa0c0dddb61893d46903d Mon Sep 17 00:00:00 2001
From: Christopher Neugebauer <chrisjrn@gmail.com>
Date: Wed, 14 Sep 2016 13:28:15 +1000
Subject: [PATCH] Adds missing_categories tag

---
 registrasion/controllers/item.py              | 22 ++++++++++++++++---
 .../templatetags/registrasion_tags.py         | 15 +++++++++++++
 2 files changed, 34 insertions(+), 3 deletions(-)

diff --git a/registrasion/controllers/item.py b/registrasion/controllers/item.py
index 9a1a9eb2..48456f76 100644
--- a/registrasion/controllers/item.py
+++ b/registrasion/controllers/item.py
@@ -1,8 +1,11 @@
 ''' NEEDS TESTS '''
 
+import operator
+
 from registrasion.models import commerce
 from registrasion.models import inventory
 
+from collections import Iterable
 from collections import namedtuple
 from django.db.models import Case
 from django.db.models import Q
@@ -34,6 +37,7 @@ class ItemController(object):
         ''' Aggregates the items that this user has purchased.
 
         Arguments:
+            cart_status (int or Iterable(int)): etc
             category (Optional[models.inventory.Category]): the category
                 of items to restrict to.
 
@@ -43,11 +47,18 @@ class ItemController(object):
 
         '''
 
-        in_cart = (
-            Q(productitem__cart__user=self.user) &
-            Q(productitem__cart__status=cart_status)
+        if not isinstance(cart_status, Iterable):
+            cart_status = [cart_status]
+
+        status_query = (
+            Q(productitem__cart__status=status) for status in cart_status
         )
 
+        in_cart = Q(productitem__cart__user=self.user)
+        in_cart = in_cart & reduce(operator.__or__, status_query)
+
+        print in_cart
+
         quantities_in_cart = When(
             in_cart,
             then="productitem__quantity",
@@ -72,6 +83,11 @@ class ItemController(object):
             out.append(ProductAndQuantity(prod, prod.quantity))
         return out
 
+    def items_pending_or_purchased(self):
+        ''' Returns the items that this user has purchased or has pending. '''
+        status = [commerce.Cart.STATUS_PAID, commerce.Cart.STATUS_ACTIVE]
+        return self._items(status)
+
     def items_purchased(self, category=None):
         ''' Aggregates the items that this user has purchased.
 
diff --git a/registrasion/templatetags/registrasion_tags.py b/registrasion/templatetags/registrasion_tags.py
index 2d6f51a4..89db7e25 100644
--- a/registrasion/templatetags/registrasion_tags.py
+++ b/registrasion/templatetags/registrasion_tags.py
@@ -20,6 +20,21 @@ def available_categories(context):
     return CategoryController.available_categories(context.request.user)
 
 
+@register.assignment_tag(takes_context=True)
+def missing_categories(context):
+    ''' Adds the categories that the user does not currently have. '''
+    user = context.request.user
+    categories_available = set(CategoryController.available_categories(user))
+    items = ItemController(user).items_pending_or_purchased()
+
+    categories_held = set()
+
+    for product, quantity in items:
+        categories_held.add(product.category)
+
+    return categories_available - categories_held
+
+
 @register.assignment_tag(takes_context=True)
 def available_credit(context):
     ''' Calculates the sum of unclaimed credit from this user's credit notes.