refactor class to its own django app

courses/classes/models.py

+from django.db import models
+from django.utils.translation import ugettext_lazy as _
+from django.utils.text import slugify
+from django.conf import settings
+
+
+class Class(models.Model):
+    name = models.CharField(
+        max_length=255,
+    )
+    assistants = models.ManyToManyField(
+        settings.AUTH_USER_MODEL,
+        verbose_name=_('Assistants'),
+        related_name='professor_classes',
+        blank=True,
+    )
+    students = models.ManyToManyField(
+        settings.AUTH_USER_MODEL,
+        related_name='classes',
+        blank=True,
+    )
+    course = models.ForeignKey(
+        'Course',
+        models.CASCADE,
+        verbose_name=_('Course'),
+    )
+    user_can_certificate = models.BooleanField(
+        _('Certification Allowed'),
+        default=False,
+    )
+    user_can_certificate_even_without_progress = models.BooleanField(
+        _('Certification Allowed Even Without Progress'),
+        default=False,
+    )
+
+    def __str__(self):
+        return u'%s @ %s' % (self.name, self.course)
+
+    def get_absolute_url(self):
+        return reverse('class', kwargs={'pk': self.id})
+
+    def add_students(self, *objs):
+        for obj in objs:
+            try:
+                c = Class.objects.get(course=self.course, students=obj)
+                c.students.remove(obj)
+            except Class.DoesNotExist:
+                pass
+            self.students.add(obj)
+
+    def remove_students(self, *objs):
+        for obj in objs:
+            self.students.remove(obj)
+            if CourseStudent.objects.filter(course=self.course,
+                                            user=obj).exists():
+                self.course.default_class.students.add(obj)
+
+    @property
+    def get_students(self):
+        from courses.models import CourseStudent
+        return CourseStudent.objects.filter(course=self.course, user__in=self.students.all()).order_by('user__first_name')

courses/classes/signals.py

+from django.db.models.signals import post_save
+
+from courses.models import CourseStudent
+from courses_certification.models import CourseCertification
+
+
+@receiver(m2m_changed, sender=Class.students.through)
+def remove_duplicate_classes(sender, instance, action, reverse, model, pk_set, **kwargs):
+    """Clean the same student in twice classes."""
+    # add student to default_class everytime that m2m cleans
+    if action == 'pre_clear':
+        default_class = instance.course.default_class
+        for student in instance.students.all():
+            student.classes.add(default_class)
+
+    # garantee that student has been subscribe in only one class
+    if action == 'post_add':
+        try:
+            for student in instance.students.all():
+                classes = student.classes.filter(course=instance.course).exclude(id=instance.id)
+                for classe in classes:
+                    student.classes.remove(classe)
+
+        # garantee that this block executes only when instance == Class.
+        except AttributeError:
+            pass

courses/models.py

@@ -19,90 +19,11 @@ from .utils import hash_name
 from .videos.models import Video
 from .notes.models import Note
 from .course_material.models import CourseMaterial
+from .classes.models import Class
 
 import re
 
 
-class Class(models.Model):
-    name = models.CharField(
-        max_length=255,
-    )
-    assistants = models.ManyToManyField(
-        settings.AUTH_USER_MODEL,
-        verbose_name=_('Assistants'),
-        related_name='professor_classes',
-        blank=True,
-    )
-    students = models.ManyToManyField(
-        settings.AUTH_USER_MODEL,
-        related_name='classes',
-        blank=True,
-    )
-    course = models.ForeignKey(
-        'Course',
-        models.CASCADE,
-        verbose_name=_('Course'),
-    )
-    user_can_certificate = models.BooleanField(
-        _('Certification Allowed'),
-        default=False,
-    )
-    user_can_certificate_even_without_progress = models.BooleanField(
-        _('Certification Allowed Even Without Progress'),
-        default=False,
-    )
-
-    def __str__(self):
-        return u'%s @ %s' % (self.name, self.course)
-
-    def get_absolute_url(self):
-        return reverse('class', kwargs={'pk': self.id})
-
-    def add_students(self, *objs):
-        for obj in objs:
-            try:
-                c = Class.objects.get(course=self.course, students=obj)
-                c.students.remove(obj)
-            except Class.DoesNotExist:
-                pass
-            self.students.add(obj)
-
-    def remove_students(self, *objs):
-        for obj in objs:
-            self.students.remove(obj)
-            if CourseStudent.objects.filter(course=self.course,
-                                            user=obj).exists():
-                self.course.default_class.students.add(obj)
-
-    @property
-    def get_students(self):
-        return CourseStudent.objects.filter(course=self.course, user__in=self.students.all()).order_by('user__first_name')
-
-
-def remove_duplicate_classes(sender, instance, action, reverse, model, pk_set, **kwargs):
-    """Clean the same student in twice classes."""
-    # add student to default_class everytime that m2m cleans
-    if action == 'pre_clear':
-        default_class = instance.course.default_class
-        for student in instance.students.all():
-            student.classes.add(default_class)
-
-    # garantee that student has been subscribe in only one class
-    if action == 'post_add':
-        try:
-            for student in instance.students.all():
-                classes = student.classes.filter(course=instance.course).exclude(id=instance.id)
-                for classe in classes:
-                    student.classes.remove(classe)
-
-        # garantee that this block executes only when instance == Class.
-        except AttributeError:
-            pass
-
-
-m2m_changed.connect(remove_duplicate_classes, sender=Class.students.through)
-
-
 class Course(models.Model):
     STATES = (
         ('draft', _('Draft')),
@@ -197,7 +118,7 @@ class Course(models.Model):
         default=False,
     )
     default_class = models.OneToOneField(
-        Class,
+        'Class',
         models.SET_NULL,
         verbose_name=_('Default Class'),
         related_name='default_course',