Move max_slots from subject to schedule

infotech/schedules/migrations/0005_schedule_max_slots.py

@@ -0,0 +1,18 @@
+# Generated by Django 4.2 on 2023-04-22 07:01
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('schedules', '0004_schedule_daytimes'),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name='schedule',
+            name='max_slots',
+            field=models.IntegerField(default=50),
+        ),
+    ]

infotech/schedules/models.py

@@ -15,6 +15,7 @@ class Schedule(models.Model):
         'daytimes.DayTime', related_name='DayTime_full_name', on_delete=models.CASCADE, null=True)
 
     date_created = models.DateTimeField(default=now, editable=False)
+    max_slots = models.IntegerField(default=50)
 
     def save(self, *args, **kwargs):
         self.name = f"{self.subject} : {self.professor}"

infotech/schedules/serializers.py

@@ -24,6 +24,14 @@ class ScheduleSerializer(serializers.HyperlinkedModelSerializer):
 
     class Meta:
         model = Schedule
-        fields = ('id', 'name', 'subject', 'daytimes', 'students_assigned',
+        fields = ('id', 'name', 'max_slots', 'subject', 'daytimes', 'students_assigned',
                   'professor', 'date_created')
         read_only_fields = ('id', 'date_created', 'name')
+
+    def validate(self, attrs):
+        students = attrs.get('students')
+        max_slots = attrs.get('max_slots')
+        if students.count() > max_slots:
+            raise serializers.ValidationError(
+                'Too many students for this subject')
+        return attrs