LIL-278. Add day_discount field to SchoolSchedule & fix calc SchoolPayment amount

apps/payment/models.py

@@ -95,11 +95,13 @@ class SchoolPayment(Payment):
         verbose_name_plural = 'Платежи за школу'
 
     def save(self, *args, **kwargs):
-        month_price_sum = SchoolSchedule.objects.filter(
+        aggregate = SchoolSchedule.objects.filter(
             weekday__in=self.weekdays,
         ).aggregate(
             models.Sum('month_price'),
-        ).get('month_price__sum', 0)
-        self.amount = month_price_sum
+            models.Sum('day_discount'),
+        )
+        month_price_sum = aggregate.get('month_price__sum', 0)
+        day_discount_sum = aggregate.get('day_discount__sum', 0) if len(self.weekdays) == 7 else 0
+        self.amount = month_price_sum - day_discount_sum
         super().save(*args, **kwargs)
-        author_balance = getattr(self, 'authorbalance', None)

apps/school/migrations/0005_schoolschedule_day_discount.py

@@ -0,0 +1,18 @@
+# Generated by Django 2.0.2 on 2018-02-22 10:00
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('school', '0004_auto_20180221_1120'),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name='schoolschedule',
+            name='day_discount',
+            field=models.DecimalField(decimal_places=2, default=0, max_digits=8, verbose_name='Скидка, в валюте'),
+        ),
+    ]

apps/school/models.py

@@ -17,6 +17,7 @@ class SchoolSchedule(models.Model):
     materials = models.TextField('Материалы')
     age = models.PositiveSmallIntegerField('Возраст', default=0)
     month_price = models.DecimalField('Цена', max_digits=8, decimal_places=2, default=0)
+    day_discount = models.DecimalField('Скидка, в валюте', max_digits=8, decimal_places=2, default=0)
 
     class Meta:
         ordering = ('weekday',)