Only generate bill if no overlap

uncloud/uncloud_pay/helpers.py

@@ -6,7 +6,7 @@ from django.db.models import Q
 from .models import Bill, Payment, PaymentMethod, Order
 from django.utils import timezone
 from django.core.exceptions import ObjectDoesNotExist
-from dateutil.relativedelta import relativedelta
+from calendar import monthrange
 
 def sum_amounts(entries):
     return reduce(lambda acc, entry: acc + entry.amount, entries, 0)
@@ -25,18 +25,24 @@ def get_payment_method_for(user):
 
     return None
 
-def beginning_of_month(date):
-    return datetime(year=date.year, date=now.month, day=0)
+def beginning_of_month(year, month):
+    tz = timezone.get_current_timezone()
+    return datetime(year=year, month=month, day=1, tzinfo=tz)
+
+def end_of_month(year, month):
+    (_, days) = monthrange(year, month)
+    tz = timezone.get_current_timezone()
+    return datetime(year=year, month=month, day=days,
+            hour=23, minute=59, second=59, tzinfo=tz)
 
 def generate_bills_for(year, month, user, allowed_delay):
     # /!\ We exclusively work on the specified year and month.
 
     # Default values for next bill (if any). Only saved at the end of
     # this method, if relevant.
-    tz = timezone.get_current_timezone()
     next_bill = Bill(owner=user,
-            starting_date=datetime(year=year, month=month, day=1, tzinfo=tz),
-            ending_date=datetime(year=year, month=month, day=28, tzinfo=tz),
+            starting_date=beginning_of_month(year, month),
+            ending_date=end_of_month(year, month),
             creation_date=timezone.now(),
             due_date=timezone.now() + allowed_delay)
 
@@ -52,7 +58,7 @@ def generate_bills_for(year, month, user, allowed_delay):
     unpaid_orders = []
     for order in orders:
         try:
-            previous_bill = order.bill.latest('-ending_date')
+            previous_bill = order.bill.latest('ending_date')
         except ObjectDoesNotExist:
             previous_bill = None
 
@@ -68,6 +74,10 @@ def generate_bills_for(year, month, user, allowed_delay):
         for order in unpaid_orders:
             order.bill.add(next_bill)
 
+        # TODO: use logger.
+        print("Generated bill {} (amount: {}) for user {}."
+                .format(next_bill.uuid, next_bill.total, user))
+
         return next_bill
 
     # Return None if no bill was created.

uncloud/uncloud_pay/models.py

@@ -1,4 +1,5 @@
 from django.db import models
+from functools import reduce
 from django.contrib.auth import get_user_model
 from django.core.validators import MinValueValidator
 from django.utils.translation import gettext_lazy as _
@@ -41,8 +42,8 @@ class Bill(models.Model):
 
     @property
     def total(self):
-        #return helpers.sum_amounts(self.entries)
-        pass
+        orders = Order.objects.filter(bill=self)
+        return reduce(lambda acc, order: acc + order.amount, orders, 0)
 
 class BillEntry():
     start_date = timezone.now()
@@ -95,12 +96,14 @@ class Order(models.Model):
                               default = RecurringPeriod.PER_MONTH)
 
 
-    # def amount(self):
+    @property
+    def amount(self):
         #     amount = recurring_price
         #     if recurring and first_month:
         #         amount += one_time_price
 
-    #     return amount # you get the picture
+        amount=1
+        return amount
 
 class PaymentMethod(models.Model):
     uuid = models.UUIDField(primary_key=True, default=uuid.uuid4, editable=False)