Tidy up the querying and move into model

This should really be in the model not in the view

RIGS/finance.py

@@ -1,16 +1,17 @@
 import cStringIO as StringIO
 import datetime
 import re
+from decimal import Decimal
 
 from django.contrib import messages
 from django.core.urlresolvers import reverse_lazy
+from django.db.models import Count, Sum, F, FloatField, Q, Value
 from django.http import Http404, HttpResponseRedirect
 from django.http import HttpResponse
 from django.shortcuts import get_object_or_404
 from django.template import RequestContext
 from django.template.loader import get_template
 from django.views import generic
-from django.db.models import Q
 from z3c.rml import rml2pdf
 
 from RIGS import models
@@ -30,19 +31,8 @@ class InvoiceIndex(generic.ListView):
         return context
 
     def get_queryset(self):
-        # Manual query is the only way I have found to do this efficiently. Not ideal but needs must
-        sql = "SELECT * FROM " \
-              "(SELECT " \
-              "(SELECT COUNT(p.amount) FROM \"RIGS_payment\" AS p WHERE p.invoice_id=\"RIGS_invoice\".id) AS \"payment_count\", " \
-              "(SELECT SUM(ei.cost * ei.quantity) FROM \"RIGS_eventitem\" AS ei WHERE ei.event_id=\"RIGS_invoice\".event_id) AS \"cost\", " \
-              "(SELECT SUM(p.amount) FROM \"RIGS_payment\" AS p WHERE p.invoice_id=\"RIGS_invoice\".id) AS \"payments\", " \
-              "\"RIGS_invoice\".\"id\", \"RIGS_invoice\".\"event_id\", \"RIGS_invoice\".\"invoice_date\", \"RIGS_invoice\".\"void\" FROM \"RIGS_invoice\") " \
-              "AS sub " \
-              "WHERE (((cost > 0.0) AND (payment_count=0)) OR (cost - payments) <> 0.0) AND void = '0'" \
-              "ORDER BY invoice_date"
-
-        query = self.model.objects.raw(sql)
-
+        query = self.model.objects.outstanding().select_related('event', 'event__organisation', 'event__person',
+                                                                'event__venue', 'event__mic')
         return query
 
 
@@ -94,6 +84,7 @@ class InvoiceVoid(generic.View):
             return HttpResponseRedirect(reverse_lazy('invoice_list'))
         return HttpResponseRedirect(reverse_lazy('invoice_detail', kwargs={'pk': object.pk}))
 
+
 class InvoiceDelete(generic.DeleteView):
     model = models.Invoice
 
@@ -114,6 +105,7 @@ class InvoiceDelete(generic.DeleteView):
     def get_success_url(self):
         return self.request.POST.get('next')
 
+
 class InvoiceArchive(generic.ListView):
     model = models.Invoice
     template_name = 'RIGS/invoice_list_archive.html'
@@ -142,11 +134,11 @@ class InvoiceWaiting(generic.ListView):
         events = self.model.objects.filter(
             (
                 Q(start_date__lte=datetime.date.today(), end_date__isnull=True) |  # Starts before with no end
-                Q(end_date__lte=datetime.date.today()) # Has end date, finishes before
-            ) & Q(invoice__isnull=True) # Has not already been invoiced
-            & Q(is_rig=True) # Is a rig (not non-rig)
-            
-            ).order_by('start_date') \
+                Q(end_date__lte=datetime.date.today())  # Has end date, finishes before
+            ) & Q(invoice__isnull=True)  # Has not already been invoiced
+            & Q(is_rig=True)  # Is a rig (not non-rig)
+
+        ).order_by('start_date') \
             .select_related('person',
                             'organisation',
                             'venue', 'mic') \

RIGS/models.py

@@ -1,11 +1,11 @@
 import datetime
 import hashlib
-import pytz
 import random
 import string
 from collections import Counter
 from decimal import Decimal
 
+import pytz
 import reversion
 from django.conf import settings
 from django.contrib.auth.models import AbstractUser
@@ -501,14 +501,34 @@ class EventCrew(models.Model):
     notes = models.TextField(blank=True, null=True)
 
 
+class InvoiceManager(models.Manager):
+    def outstanding(self):
+        return self.annotate(
+            _payment_total=models.Sum(models.F('payment__amount'))
+        ).annotate(
+            _sum_total=models.Sum(models.F('event__items__cost') * models.F('event__items__quantity'),
+                                  output_field=models.DecimalField(decimal_places=2))
+        # ).annotate(
+        #     _balance=models.ExpressionWrapper(models.F('_sum_total') - models.F('_payment_total'),
+        #                                       models.DecimalField(decimal_places=2))
+        # ).filter(
+        #     models.Q(_balance__isnull=True) |
+        #     ~models.Q(_sum_total=models.F('_payment_total'))
+        )
+
+
 @python_2_unicode_compatible
 class Invoice(models.Model):
     event = models.OneToOneField('Event')
     invoice_date = models.DateField(auto_now_add=True)
     void = models.BooleanField(default=False)
 
+    objects = InvoiceManager()
+
     @property
     def sum_total(self):
+        if getattr(self, '_sum_total', None):
+            return Decimal(getattr(self, '_sum_total'))
         return self.event.sum_total
 
     @property
@@ -517,6 +537,10 @@ class Invoice(models.Model):
 
     @property
     def payment_total(self):
+        if hasattr(self, '_payment_total') and hasattr(self, '_payment_count'):
+            if getattr(self, '_payment_count') == 0:
+                return Decimal(0.00)
+            return Decimal(getattr(self, '_payment_total', 0.00))
         total = self.payment_set.aggregate(total=models.Sum('amount'))['total']
         if total:
             return total