Update course members sections

app/serializers/course_member.py

@@ -5,6 +5,7 @@
 from app.serializers.attribute import AttributeResponseSerializer
 from app.serializers.relationship import RelationshipSerializer
 from app.serializers.section import SectionSerializer
+from app.models.section import Section
 
 
 class CourseMemberSerializer(serializers.ModelSerializer):
@@ -21,3 +22,25 @@ class CourseMemberSerializer(serializers.ModelSerializer):
     class Meta:
         model = CourseMember
         fields = "__all__"
+
+
+class UpdateStudentSectionsRequest(serializers.Serializer):
+    sections = serializers.ListField(
+        child=serializers.IntegerField(),
+        required=True,
+        error_messages={
+            "required": "Sections is required.",
+        },
+    )
+
+    def validate_sections(self, value):
+        course = self.context.get("course")
+        sections_passed_in = set(value)
+        course_sections_ids = Section.objects.filter(
+            course=course, id__in=sections_passed_in
+        )
+        if len(sections_passed_in) != course_sections_ids.count():
+            raise serializers.ValidationError(
+                "One or more sections do not exist or are not part of the course."
+            )
+        return value

app/views/course_member.py

@@ -1,11 +1,21 @@
 from rest_framework import viewsets
 
-from app.models.course_member import CourseMember
+from app.models.course_member import CourseMember, UserRole
 from app.paginators.pagination import ExamplePagination
+from app.models.section import Section
 from app.filters.course_member import FilterStudents
-from app.serializers.course_member import CourseMemberSerializer
+from app.serializers.course_member import (
+    CourseMemberSerializer,
+    UpdateStudentSectionsRequest,
+)
 
 from rest_framework.response import Response
+from rest_framework.decorators import action
+from rest_framework import status
+
+from django.db import transaction
+from django.core.exceptions import ValidationError
+from rest_framework.exceptions import APIException
 
 
 class CourseMemberViewSet(viewsets.ModelViewSet):
@@ -30,3 +40,50 @@ def get_students_by_course(self, request, course=None, *args, **kwargs):
         else:
             serializer = self.get_serializer(queryset, many=True)
             return Response(serializer.data)
+
+    @action(detail=True, methods=["put"], url_path="update-sections")
+    @transaction.atomic
+    def update_sections(self, request, *args, **kwargs):
+        try:
+            course_member = self.get_object()
+
+            if course_member.role != UserRole.STUDENT:
+                return Response(
+                    {
+                        "errors": {
+                            "message": "Only students can be assigned to sections."
+                        }
+                    },
+                    status=status.HTTP_400_BAD_REQUEST,
+                )
+
+            request_body_serializer = UpdateStudentSectionsRequest(
+                instance=course_member,
+                data=request.data,
+                context={"course": course_member.course},
+            )
+            if request_body_serializer.is_valid(raise_exception=True):
+                section_ids = request_body_serializer._validated_data.get("sections")
+                proposed_sections_update = Section.objects.filter(
+                    id__in=section_ids, course=course_member.course
+                )
+                course_member.sections.set(proposed_sections_update)
+                course_member.save()
+                response_course_member_serializer = self.get_serializer(course_member)
+                return Response(response_course_member_serializer.data)
+
+        except Exception as exc:
+            errors = []
+            if isinstance(exc, APIException):
+                if isinstance(exc.detail, dict):
+                    for field, error_list in exc.detail.items():
+                        for error in error_list:
+                            errors.append({"message": str(error)})
+                else:
+                    errors.append({"message": exc.detail})
+            if isinstance(exc, ValidationError):
+                for field, error_list in exc.detail.items():
+                    for error in error_list:
+                        errors.append({"message": str(error)})
+            response = Response({"errors": errors}, status=status.HTTP_400_BAD_REQUEST)
+            return response