From 12d21f3c49c59b9207956f361ef0a541215d1b1f Mon Sep 17 00:00:00 2001
From: Gabriellvl <vanlangenhovefga@gmail.com>
Date: Mon, 7 Apr 2025 23:48:35 +0200
Subject: [PATCH] fix: check student in klas, conflict error

---
 backend/src/services/students.ts | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/backend/src/services/students.ts b/backend/src/services/students.ts
index dc40e468..a8300db5 100644
--- a/backend/src/services/students.ts
+++ b/backend/src/services/students.ts
@@ -23,6 +23,8 @@ import { GroupDTO } from '@dwengo-1/common/interfaces/group';
 import { SubmissionDTO, SubmissionDTOId } from '@dwengo-1/common/interfaces/submission';
 import { QuestionDTO, QuestionId } from '@dwengo-1/common/interfaces/question';
 import { ClassJoinRequestDTO } from '@dwengo-1/common/interfaces/class-join-request';
+import {BadRequestException} from "../exceptions/bad-request-exception";
+import {ConflictException} from "../exceptions/conflict-exception";
 
 export async function getAllStudents(full: boolean): Promise<StudentDTO[] | string[]> {
     const studentRepository = getStudentRepository();
@@ -135,6 +137,10 @@ export async function createClassJoinRequest(username: string, classId: string):
     const student = await fetchStudent(username); // Throws error if student not found
     const cls = await fetchClass(classId);
 
+    if (cls.students.contains(student)) {
+        throw new ConflictException("Student already in this class");
+    }
+
     const request = mapToStudentRequest(student, cls);
     await requestRepo.save(request, { preventOverwrite: true });
     return mapToStudentRequestDTO(request);