lessons count enhanced and synced with lesson model.

apps/course/management/commands/sync_course_lessons_count.py

@@ -0,0 +1,42 @@
+from django.core.management.base import BaseCommand
+
+from apps.course.models.course import Course
+
+
+class Command(BaseCommand):
+    help = "Recalculate lessons_count for all courses based on active assigned course lessons."
+
+    def add_arguments(self, parser):
+        parser.add_argument(
+            '--dry-run',
+            action='store_true',
+            help='Preview updates without saving changes.',
+        )
+
+    def handle(self, *args, **options):
+        dry_run = options['dry_run']
+        updated_courses = 0
+
+        for course in Course.objects.all().order_by('id'):
+            actual_count = course.lessons.filter(is_active=True).count()
+
+            if course.lessons_count != actual_count:
+                updated_courses += 1
+                self.stdout.write(
+                    f"Course {course.id} ({course.slug}): {course.lessons_count} -> {actual_count}"
+                )
+                if not dry_run:
+                    Course.objects.filter(pk=course.pk).update(lessons_count=actual_count)
+
+        if dry_run:
+            self.stdout.write(
+                self.style.WARNING(
+                    f"Dry run complete. {updated_courses} course(s) would be updated."
+                )
+            )
+        else:
+            self.stdout.write(
+                self.style.SUCCESS(
+                    f"Sync complete. {updated_courses} course(s) updated."
+                )
+            )

apps/course/models/course.py

@@ -128,6 +128,23 @@ class Course(models.Model):
     def is_student_participant(self, student):
         return self.participants.filter(student=student).exists()
 
+    @classmethod
+    def recalculate_lessons_count_for_course(cls, course_id):
+        if not course_id:
+            return 0
+
+        from apps.course.models.lesson import CourseLesson
+
+        lessons_count = CourseLesson.objects.filter(
+            course_id=course_id,
+            is_active=True,
+        ).count()
+        cls.objects.filter(pk=course_id).update(lessons_count=lessons_count)
+        return lessons_count
+
+    def recalculate_lessons_count(self):
+        return self.__class__.recalculate_lessons_count_for_course(self.pk)
+
 
     def save(self, *args, **kwargs):
         if not self.slug:

apps/course/models/lesson.py

@@ -117,7 +117,7 @@ class CourseLesson(models.Model):
     
     def save(self, *args, **kwargs):
         # 👇 3. Auto-sync v1 and v2 relations!
-        if self.chapter and not getattr(self, 'course_id', None):
+        if self.chapter and getattr(self, 'course_id', None) != self.chapter.course_id:
             self.course = self.chapter.course
             
         if not self.title:

apps/course/signals.py

@@ -1,8 +1,10 @@
 from apps.course.models import Course
 from apps.chat.models import RoomMessage
+from apps.course.models.course import Course
+from apps.course.models.lesson import CourseLesson
 from django.db.models import Q
 
-from django.db.models.signals import post_save, post_delete
+from django.db.models.signals import post_save, post_delete, pre_save
 from django.dispatch import receiver
 from django.core.cache import cache
 from django.contrib.auth import get_user_model
@@ -80,3 +82,44 @@ def sync_course_chat_locks(sender, instance, **kwargs):
             Q(initiator_id=instance.professor_id, recipient_id__in=student_ids) | 
             Q(initiator_id__in=student_ids, recipient_id=instance.professor_id)
         ).update(is_locked=instance.is_professor_chat_locked)
+
+
+def _recalculate_course_lessons_count(course_id):
+    Course.recalculate_lessons_count_for_course(course_id)
+
+
+@receiver(pre_save, sender=CourseLesson)
+def capture_previous_course_lesson_state(sender, instance, **kwargs):
+    if not instance.pk:
+        instance._previous_course_id = None
+        instance._previous_is_active = None
+        return
+
+    previous = sender.objects.filter(pk=instance.pk).values('course_id', 'is_active').first()
+    if previous:
+        instance._previous_course_id = previous['course_id']
+        instance._previous_is_active = previous['is_active']
+    else:
+        instance._previous_course_id = None
+        instance._previous_is_active = None
+
+
+@receiver(post_save, sender=CourseLesson)
+def sync_lessons_count_on_course_lesson_save(sender, instance, **kwargs):
+    affected_course_ids = {instance.course_id}
+
+    previous_course_id = getattr(instance, '_previous_course_id', None)
+    previous_is_active = getattr(instance, '_previous_is_active', None)
+    if previous_course_id and previous_course_id != instance.course_id:
+        affected_course_ids.add(previous_course_id)
+
+    if previous_is_active is not None and previous_is_active != instance.is_active and previous_course_id:
+        affected_course_ids.add(previous_course_id)
+
+    for course_id in affected_course_ids:
+        _recalculate_course_lessons_count(course_id)
+
+
+@receiver(post_delete, sender=CourseLesson)
+def sync_lessons_count_on_course_lesson_delete(sender, instance, **kwargs):
+    _recalculate_course_lessons_count(instance.course_id)

apps/course/tests/test_lessons_count_sync.py

@@ -0,0 +1,174 @@
+from io import StringIO
+
+from django.core.files.uploadedfile import SimpleUploadedFile
+from django.core.management import call_command
+from django.test import TestCase
+
+from apps.account.models import ProfessorUser
+from apps.course.models.course import Course, CourseCategory
+from apps.course.models.lesson import CourseChapter, CourseLesson, Lesson
+
+
+class LessonsCountSyncTests(TestCase):
+    def setUp(self):
+        self.professor = ProfessorUser.objects.create(
+            email='prof-sync@example.com',
+            fullname='Professor Sync',
+            experience_years=5,
+        )
+        self.category = CourseCategory.objects.create(
+            name='Sync Category',
+            slug='sync-category',
+        )
+
+    def _create_course(self, slug, title, lessons_count=0):
+        thumbnail = SimpleUploadedFile(f'{slug}.jpg', b'filecontent', content_type='image/jpeg')
+        return Course.objects.create(
+            title=title,
+            slug=slug,
+            category=self.category,
+            professor=self.professor,
+            thumbnail=thumbnail,
+            video_type=Course.VedioTypeChoices.YOUTUBE_LINK,
+            video_link='https://example.com/video',
+            is_online=False,
+            level=Course.LevelChoices.BEGINNER,
+            duration=10,
+            lessons_count=lessons_count,
+            description='Description',
+            short_description='Short description',
+            status=Course.StatusChoices.ONGOING,
+            is_free=True,
+        )
+
+    def _create_chapter(self, course, title='Chapter', priority=1):
+        return CourseChapter.objects.create(
+            course=course,
+            title=title,
+            priority=priority,
+            is_active=True,
+        )
+
+    def _create_course_lesson(self, course, chapter=None, title='Lesson', is_active=True, priority=1):
+        if chapter is None:
+            chapter = self._create_chapter(course, title=f'{course.title} Chapter', priority=priority)
+
+        lesson = Lesson.objects.create(
+            title=title,
+            content_type=Lesson.ContentTypeChoices.VIDEO_FILE,
+            duration=5,
+        )
+        return CourseLesson.objects.create(
+            course=course,
+            chapter=chapter,
+            lesson=lesson,
+            priority=priority,
+            is_active=is_active,
+        )
+
+    def test_creating_active_course_lesson_updates_lessons_count(self):
+        course = self._create_course('create-active-course', 'Create Active Course')
+
+        self._create_course_lesson(course, title='Lesson 1')
+
+        course.refresh_from_db()
+        self.assertEqual(course.lessons_count, 1)
+
+    def test_deleting_active_course_lesson_updates_lessons_count(self):
+        course = self._create_course('delete-active-course', 'Delete Active Course')
+        course_lesson = self._create_course_lesson(course, title='Lesson 1')
+
+        course.refresh_from_db()
+        self.assertEqual(course.lessons_count, 1)
+
+        course_lesson.delete()
+
+        course.refresh_from_db()
+        self.assertEqual(course.lessons_count, 0)
+
+    def test_toggling_is_active_updates_lessons_count(self):
+        course = self._create_course('toggle-active-course', 'Toggle Active Course')
+        course_lesson = self._create_course_lesson(course, title='Lesson 1', is_active=False)
+
+        course.refresh_from_db()
+        self.assertEqual(course.lessons_count, 0)
+
+        course_lesson.is_active = True
+        course_lesson.save()
+
+        course.refresh_from_db()
+        self.assertEqual(course.lessons_count, 1)
+
+        course_lesson.is_active = False
+        course_lesson.save()
+
+        course.refresh_from_db()
+        self.assertEqual(course.lessons_count, 0)
+
+    def test_moving_course_lesson_updates_old_and_new_course_counts(self):
+        old_course = self._create_course('old-course', 'Old Course')
+        new_course = self._create_course('new-course', 'New Course')
+        old_chapter = self._create_chapter(old_course, title='Old Chapter', priority=1)
+        new_chapter = self._create_chapter(new_course, title='New Chapter', priority=1)
+        course_lesson = self._create_course_lesson(
+            old_course,
+            chapter=old_chapter,
+            title='Lesson 1',
+            is_active=True,
+            priority=1,
+        )
+
+        old_course.refresh_from_db()
+        new_course.refresh_from_db()
+        self.assertEqual(old_course.lessons_count, 1)
+        self.assertEqual(new_course.lessons_count, 0)
+
+        course_lesson.chapter = new_chapter
+        course_lesson.save()
+
+        old_course.refresh_from_db()
+        new_course.refresh_from_db()
+        self.assertEqual(old_course.lessons_count, 0)
+        self.assertEqual(new_course.lessons_count, 1)
+
+    def test_inactive_lessons_are_not_counted(self):
+        course = self._create_course('inactive-course', 'Inactive Course')
+
+        self._create_course_lesson(course, title='Lesson 1', is_active=False)
+        self._create_course_lesson(course, title='Lesson 2', is_active=True, priority=2)
+
+        course.refresh_from_db()
+        self.assertEqual(course.lessons_count, 1)
+
+    def test_sync_course_lessons_count_command_updates_mismatched_courses(self):
+        first_course = self._create_course('sync-first-course', 'Sync First Course', lessons_count=99)
+        second_course = self._create_course('sync-second-course', 'Sync Second Course', lessons_count=7)
+
+        self._create_course_lesson(first_course, title='Lesson 1', is_active=True)
+        self._create_course_lesson(first_course, title='Lesson 2', is_active=False, priority=2)
+        self._create_course_lesson(second_course, title='Lesson 3', is_active=True)
+        self._create_course_lesson(second_course, title='Lesson 4', is_active=True, priority=2)
+
+        Course.objects.filter(pk=first_course.pk).update(lessons_count=99)
+        Course.objects.filter(pk=second_course.pk).update(lessons_count=7)
+
+        stdout = StringIO()
+        call_command('sync_course_lessons_count', stdout=stdout)
+
+        first_course.refresh_from_db()
+        second_course.refresh_from_db()
+        self.assertEqual(first_course.lessons_count, 1)
+        self.assertEqual(second_course.lessons_count, 2)
+        self.assertIn('Sync complete. 2 course(s) updated.', stdout.getvalue())
+
+    def test_sync_course_lessons_count_command_dry_run_does_not_persist_changes(self):
+        course = self._create_course('sync-dry-course', 'Sync Dry Course', lessons_count=5)
+        self._create_course_lesson(course, title='Lesson 1', is_active=True)
+        Course.objects.filter(pk=course.pk).update(lessons_count=5)
+
+        stdout = StringIO()
+        call_command('sync_course_lessons_count', '--dry-run', stdout=stdout)
+
+        course.refresh_from_db()
+        self.assertEqual(course.lessons_count, 5)
+        self.assertIn('Dry run complete. 1 course(s) would be updated.', stdout.getvalue())