feat: update CourseDetailSerializer to use SerializerMethodField for professor and add is_professor field

apps/course/serializers/course.py

@@ -87,7 +87,7 @@ class CourseListSerializer(serializers.ModelSerializer):
     
 class CourseDetailSerializer(serializers.ModelSerializer):
     category = CourseCategorySerializer()
-    professor = UserProfileSerializer()
+    professor = serializers.SerializerMethodField()
     thumbnail = serializers.SerializerMethodField()
     participant_count = serializers.SerializerMethodField()
     access = serializers.SerializerMethodField()
@@ -100,6 +100,7 @@ class CourseDetailSerializer(serializers.ModelSerializer):
     discount_percentage = serializers.SerializerMethodField()
     final_price = serializers.SerializerMethodField()
     is_free = serializers.SerializerMethodField()
+    is_professor = serializers.SerializerMethodField()
 
     class Meta:
         model = Course        
@@ -111,6 +112,7 @@ class CourseDetailSerializer(serializers.ModelSerializer):
             'access',
             'participant_count',
             'professor',
+            'is_professor',
             'thumbnail',
             'video_type',
             'video_file',
@@ -214,6 +216,12 @@ class CourseDetailSerializer(serializers.ModelSerializer):
                 return False
             return True            
         return False
+    
+    def get_professor(self, obj):
+        """Return the course professor's profile using UserProfileSerializer"""
+        if obj.professor:
+            return UserProfileSerializer(obj.professor, context=self.context).data
+        return None
             
     def get_is_professor(self, obj):
         if professor := self._get_authenticated_user():