4 - Calculate the Order Total

src/orders/models.py

@@ -1,5 +1,5 @@
 from django.db import models
-from django.db.models.signals import pre_save
+from django.db.models.signals import pre_save, post_save
 
 
 from carts.models import Cart
@@ -26,6 +26,14 @@ class Order(models.Model):
     def __str__(self):
         return self.order_id
 
+    def update_total(self):
+        cart_total = self.cart.total
+        shipping_total = self.shipping_total
+        new_total = cart_total + shipping_total
+        self.total = new_total
+        self.save()
+        return new_total
+
 
 def pre_save_create_order_id(sender, instance, *args, **kwargs):
     if not instance.order_id:
@@ -34,6 +42,25 @@ def pre_save_create_order_id(sender, instance, *args, **kwargs):
 pre_save.connect(pre_save_create_order_id, sender=Order)
 
 
+def post_save_cart_total(sender, instance, created, *args, **kwargs):
+    if not created:
+        cart_obj = instance
+        cart_total = cart_obj.total
+        cart_id = cart_obj.id
+        qs = Order.objects.filter(cart__id=cart_id)
+        if qs.count() == 1:
+            order_obj = qs.first()
+            order_obj.update_total()
+
+post_save.connect(post_save_cart_total, sender=Cart)
+
+
+def post_save_order(sender, instance, created, *args, **kwargs):
+    print("running")
+    if created:
+        print("Updating... first")
+        instance.update_total()
+
+
+post_save.connect(post_save_order, sender=Order)
 
-# generate the order id?
-# generate the order total?