Move bill generation logic to Bill class, initial work for prepaid

uncloud/uncloud_pay/management/commands/handle-overdue-bills.py

@@ -1,12 +1,12 @@
 from django.core.management.base import BaseCommand
 from uncloud_auth.models import User
-from uncloud_pay.models import Order, Bill, get_balance_for
+from uncloud_pay.models import Bill
 
 from datetime import timedelta
 from django.utils import timezone
 
 class Command(BaseCommand):
-    help = 'Generate bills and charge customers if necessary.'
+    help = 'Take action on overdue bills.'
 
     def add_arguments(self, parser):
         pass
@@ -15,28 +15,9 @@ class Command(BaseCommand):
         users = User.objects.all()
         print("Processing {} users.".format(users.count()))
         for user in users:
-            balance = get_balance_for(user)
-            if balance < 0:
-                print("User {} has negative balance ({}), checking for overdue bills."
-                        .format(user.username, balance))
-
-                # Get bills DESCENDING by creation date (= latest at top).
-                bills = Bill.objects.filter(
-                        owner=user,
-                        due_date__lt=timezone.now()
-                        ).order_by('-creation_date')
-                overdue_balance = abs(balance)
-                overdue_bills = []
-                for bill in bills:
-                    if  overdue_balance < 0:
-                        break # XXX: I'm (fnux) not fond of breaks!
-
-                    overdue_balance -= bill.amount
-                    overdue_bills.append(bill)
-
-                for bill in overdue_bills:
-                    print("/!\ Overdue bill for {}, {} with amount {}"
-                            .format(user.username, bill.uuid, bill.amount))
-                    # TODO: take action?
+            for bill in Bill.get_overdue_for(user):
+                print("/!\ Overdue bill for {}, {} with amount {}"
+                        .format(user.username, bill.uuid, bill.amount))
+                # TODO: take action?
 
         print("=> Done.")

uncloud/uncloud_pay/models.py

@@ -18,10 +18,14 @@ import uncloud_pay.stripe
 from uncloud_pay.helpers import beginning_of_month, end_of_month
 
 from decimal import Decimal
+
 # Define DecimalField properties, used to represent amounts of money.
 AMOUNT_MAX_DIGITS=10
 AMOUNT_DECIMALS=2
 
+# Used to generate bill due dates.
+BILL_PAYMENT_DELAY=timedelta(days=10)
+
 # See https://docs.djangoproject.com/en/dev/ref/models/fields/#field-choices-enum-types
 class RecurringPeriod(models.TextChoices):
     ONE_TIME   = 'ONCE', _('Onetime')
@@ -86,6 +90,20 @@ class Payment(models.Model):
                               default='unknown')
     timestamp = models.DateTimeField(editable=False, auto_now_add=True)
 
+    # WIP prepaid and service activation logic by fnux.
+    ## We override save() in order to active products awaiting payment.
+    #def save(self, *args, **kwargs):
+    #    # TODO: only run activation logic on creation, not on update.
+    #    unpaid_bills_before_payment = Bill.get_unpaid_for(self.owner)
+    #    super(Payment, self).save(*args, **kwargs) # Save payment in DB.
+    #    unpaid_bills_after_payment = Bill.get_unpaid_for(self.owner)
+
+    #    newly_paid_bills = list(
+    #            set(unpaid_bills_before_payment) - set(unpaid_bills_after_payment))
+    #    for bill in newly_paid_bills:
+    #        bill.activate_orders()
+
+
 class PaymentMethod(models.Model):
     uuid = models.UUIDField(primary_key=True, default=uuid.uuid4, editable=False)
     owner = models.ForeignKey(get_user_model(),
@@ -183,7 +201,7 @@ class Bill(models.Model):
         return self.ending_date < timezone.now()
 
     @staticmethod
-    def generate_for(year, month, user, allowed_delay):
+    def generate_for(year, month, user):
         # /!\ We exclusively work on the specified year and month.
 
         # Default values for next bill (if any). Only saved at the end of
@@ -192,7 +210,7 @@ class Bill(models.Model):
                 starting_date=beginning_of_month(year, month),
                 ending_date=end_of_month(year, month),
                 creation_date=timezone.now(),
-                due_date=timezone.now() + allowed_delay)
+                due_date=timezone.now() + BILL_PAYMENT_DELAY)
 
         # Select all orders active on the request period.
         orders = Order.objects.filter(
@@ -231,6 +249,35 @@ class Bill(models.Model):
         # Return None if no bill was created.
         return None
 
+    @staticmethod
+    def get_unpaid_for(user):
+        balance = get_balance_for(user)
+        unpaid_bills = []
+        # No unpaid bill if balance is positive.
+        if balance >= 0:
+            return []
+        else:
+            bills = Bill.objects.filter(
+                    owner=user,
+                    due_date__lt=timezone.now()
+                    ).order_by('-creation_date')
+
+            # Amount to be paid by the customer.
+            unpaid_balance = abs(balance)
+            for bill in bills:
+                if  unpaid_balance < 0:
+                    break
+
+                    unpaid_balance -= bill.amount
+                    unpaid_bills.append(bill)
+
+            return unpaid_bills
+
+    @staticmethod
+    def get_overdue_for(user):
+        unpaid_bills = Bill.get_unpaid_for(user)
+        return list(filter(lambda bill: bill.due_date > timezone.now(), unpaid_bills))
+
 class BillRecord():
     """
     Entry of a bill, dynamically generated from order records.
@@ -345,9 +392,6 @@ class Order(models.Model):
                 recurring_price=recurring_price,
                 description=description)
 
-    def generate_bill(self):
-        pass
-
 
 class OrderRecord(models.Model):
     """
@@ -398,7 +442,7 @@ class Product(models.Model):
 
     status = models.CharField(max_length=32,
             choices=ProductStatus.choices,
-            default=ProductStatus.AWAITING_PAYMENT)
+            default=ProductStatus.PENDING)
 
     order = models.ForeignKey(Order,
                               on_delete=models.CASCADE,