feat: improved order payment lifecycle

shop/utils.py

@@ -7,6 +7,7 @@ from decimal import Decimal
 import pyDes
 from django.contrib.auth import get_user_model
 from django.db import transaction
+from django.db.models import Sum
 from django.utils import timezone
 from django.utils.text import gettext_lazy as _
 
@@ -20,8 +21,10 @@ from shop.models import (
     ProductBatch,
     ProductPrice,
     ShippingMethod,
+    CartItem,
 )
 from shop.settings import ERROR_CODES
+from shop.signals import clear_cart
 
 User = get_user_model()
 
@@ -114,6 +117,7 @@ def create_order_from_cart(
         shipping_method=shipping_method,
         user=cart.user,
         email=email,
+        from_cart=cart,
     )
 
     for item in cart.items.all():
@@ -261,15 +265,34 @@ def validate_expiry_date(expiry_date: str):
     return True
 
 
-def pay_order(order: Order, amount_paid: Decimal):
-    with transaction.atomic() as tx:
+def update_order_payment_status(order: Order):
+    if order.amount_paid >= order.total:
+        order.status = Order.Statuses.STATUS_PAID
+    elif order.status == Order.Statuses.STATUS_PAID and order.amount_paid == Decimal(
+        "0.00"
+    ):
+        order.status = Order.Statuses.STATUS_RETURNED
+    else:
+        order.status = Order.Statuses.STATUS_PENDING
+
+    order.save()
+
+
+def delete_cart_items_from_order(order):
+    if order.status == Order.Statuses.STATUS_PAID and order.from_cart:
+        CartItem.objects.filter(cart=order.from_cart).delete()
+
+
+def add_payment_to_order(order: Order, amount):
+    with transaction.atomic():
         payment = Payment.objects.create(
-            amount=amount_paid,
+            amount=amount,
             order=order,
             user=order.user,
             method=Payment.MethodChoices.REDSYS,
         )
+        order.amount_paid += payment.amount
 
-        if amount_paid >= order.total:
-            order.status = Order.Statuses.STATUS_PAID
-            order.save()
+        update_order_payment_status(order)
+
+    delete_cart_items_from_order(order)