WIP revamped bill logic

uncloud/uncloud_pay/models.py

@@ -2,6 +2,7 @@ from django.db import models
 from django.contrib.auth import get_user_model
 from django.core.validators import MinValueValidator
 from django.utils.translation import gettext_lazy as _
+from django.utils import timezone
 
 import uuid
 
@@ -31,16 +32,49 @@ class Bill(models.Model):
     valid = models.BooleanField(default=True)
 
     @property
-    def amount(self):
-        orders = Order.objects.filter(bill=self)
-        amount = 0
-        for order in orders:
-            amount += order.recurring_price
-
-        return amount
+    def entries(self):
+        # TODO: return list of Bill entries, extract from linked order
+        # for each related order
+        #   for each product
+        #       build BillEntry
+        return []
 
+    @property
+    def total(self):
+        #return helpers.sum_amounts(self.entries)
+        pass
+
+class BillEntry():
+    start_date = timezone.now()
+    end_date = timezone.now()
+    recurring_period = RecurringPeriod.PER_MONTH
+    recurring_price = 0
+    amount = 0
+    description = ""
 
 
+# /!\ BIG FAT WARNING /!\ #
+#
+# Order are assumed IMMUTABLE and used as SOURCE OF TRUST for generating
+# bills. Do **NOT** mutate then!
+#
+# Why? We need to store the state somewhere since product are mutable (e.g.
+# adding RAM to VM, changing price of 1GB of RAM, ...). An alternative could
+# have been to only store the state in bills but would have been more
+# confusing: the order is a 'contract' with the customer, were both parts
+# agree on deal => That's what we want to keep archived.
+#
+# SOON:
+#
+# We'll need to add some kind of OrderEntry table (each order might have
+# multiple entries) storing: recurring_price, recurring_period, setup_fee, description
+#
+# FOR NOW:
+#
+# We dynamically get pricing from linked product, as they are not updated in
+# this stage of development.
+#
+# /!\ BIG FAT WARNING /!\ #
 class Order(models.Model):
     uuid = models.UUIDField(primary_key=True, default=uuid.uuid4, editable=False)
     owner = models.ForeignKey(get_user_model(),
@@ -56,22 +90,11 @@ class Order(models.Model):
                                   editable=False,
                                   blank=True)
 
-
-    recurring_price = models.DecimalField(
-            max_digits=AMOUNT_MAX_DIGITS,
-            decimal_places=AMOUNT_DECIMALS,
-            validators=[MinValueValidator(0)],
-            editable=False)
-    one_time_price = models.DecimalField(
-            max_digits=AMOUNT_MAX_DIGITS,
-            decimal_places=AMOUNT_DECIMALS,
-            validators=[MinValueValidator(0)],
-            editable=False)
-
     recurring_period = models.CharField(max_length=32,
                               choices = RecurringPeriod.choices,
                               default = RecurringPeriod.PER_MONTH)
 
+
     # def amount(self):
     #     amount = recurring_price
     #     if recurring and first_month:
@@ -133,9 +156,6 @@ class Payment(models.Model):
                               default='unknown')
     timestamp = models.DateTimeField(editable=False, auto_now_add=True)
 
-
-
-
 class Product(models.Model):
     uuid = models.UUIDField(primary_key=True, default=uuid.uuid4, editable=False)
     owner = models.ForeignKey(get_user_model(),