Sorts users after last purchase

main/models.py

@@ -2,6 +2,7 @@ from django.contrib.auth.models import User
 from django.db import models
 from django.db.models.signals import post_save
 from django.dispatch import receiver
+from datetime import datetime
 
 class Product(models.Model):
 
@@ -53,6 +54,18 @@ class UserProfile(models.Model):
 	balance = models.FloatField(default=0.0)
 	image = models.ImageField(upload_to='users', blank=True)
 
+        def last_purchase(self):
+            if len(self.user.order_set.all()) == 0:
+                return None
+            return self.user.order_set.order_by('created').reverse()[0]
+
+        def last_purchase_date(self):
+            last = self.last_purchase()
+            if last:
+                return last.created
+            else:
+                return datetime.min
+
 	def __unicode__(self):
 		return "{0}".format(self.user)
 

main/views.py

@@ -31,6 +31,8 @@ def home(request):
 def register(request):
     products = Product.objects.all()
     users = User.objects.filter(userprofile__balance__gt=0)
+    # sort users after user's last purchase time
+    users = sorted(users, key=lambda u: u.get_profile().last_purchase_date(), reverse=True)
     users_js = users_format_js(users)
 
     # multiple orderlines (one per product)
@@ -80,7 +82,7 @@ def register(request):
     return render_to_response('register.html', locals(), context_instance=RequestContext(request))
 
 def deposit(request):
-    users = User.objects.all()
+    users = User.objects.all().order_by('first_name','last_name')
     users_js = users_format_js(users)
 
     if request.method == "POST":
@@ -109,7 +111,9 @@ def logout(request):
     return render_to_response('registration/logout.html', locals(), context_instance=RequestContext(request))
 
 def users_format_js(users):
-    users = "[{0}]".format(
-        ",".join(['"'+user[0]+ ' ' + user[1][:1] + '"' for user in users.values_list('first_name','last_name')]))
-    return users
+    users_js = []
+    for user in users:
+        users_js.append('"' + user.first_name + ' ' + user.last_name[:1] + '"')
+    users_js = "[{0}]".format(",".join(users_js))
+    return users_js