Development: Disable LTI exercise link button when no exercise is selected

src/main/webapp/app/lti/lti13-deep-linking.component.html

@@ -75,9 +75,15 @@ <h4 class="modal-title" jhiTranslate="artemisApp.lti13.selectContentFromCourse"
     </div>
     <div class="modal-footer">
         <div>
-            <button type="submit" (click)="sendDeepLinkRequest()" class="btn btn-success">
-                <span class="d-sm-inline" jhiTranslate="artemisApp.lti13.deepLinking.link"></span>
-            </button>
+            @if (selectedExercises?.size) {
+                <button type="submit" (click)="sendDeepLinkRequest()" class="btn btn-success">
+                    <span class="d-sm-inline" jhiTranslate="artemisApp.lti13.deepLinking.link"></span>
+                </button>
+            } @else {
+                <button type="submit" class="btn btn-success disabled">
+                    <span class="d-sm-inline" jhiTranslate="artemisApp.lti13.deepLinking.selectToLink"></span>
+                </button>
+            }
         </div>
     </div>
 </div>

src/main/webapp/app/lti/lti13-deep-linking.component.ts

@@ -130,7 +130,7 @@ export class Lti13DeepLinkingComponent implements OnInit {
      * If an exercise is selected, it sends a POST request to initiate deep linking.
      */
     sendDeepLinkRequest() {
-        if (this.selectedExercises) {
+        if (this.selectedExercises?.size) {
             const ltiIdToken = this.sessionStorageService.retrieve('ltiIdToken') ?? '';
             const clientRegistrationId = this.sessionStorageService.retrieve('clientRegistrationId') ?? '';
             const exerciseIds = Array.from(this.selectedExercises).join(',');
@@ -154,6 +154,8 @@ export class Lti13DeepLinkingComponent implements OnInit {
                     onError(this.alertService, error);
                 },
             });
+        } else {
+            this.alertService.error('artemisApp.lti13.deepLinking.selectToLink');
         }
     }
 }

src/main/webapp/i18n/de/lti.json

@@ -87,6 +87,7 @@
                 "linkedSuccessfully": "Verknüpfung der Übungen erfolgreich",
                 "linkedFailed": "Fehler beim Deep-Linking",
                 "link": "Verlinken",
+                "selectToLink": "Übungen zum Verlinken auswählen",
                 "unknownError": "Aufgrund eines unbekannten Fehlers nicht erfolgreich. Bitte kontaktiere einen Admin!",
                 "noCoursesError": "Keiner deiner Artemis-Kurse hat LTI aktiviert. Bitte fahre mit der Konfiguration mindestens eines Kurses fort.",
                 "learnMore": "Erfahre mehr über die Einrichtung von LTI in einem Kurs.."

src/main/webapp/i18n/en/lti.json

@@ -87,6 +87,7 @@
                 "linkedSuccessfully": "Linked exercises successfully",
                 "linkedFailed": "Error during deep linking",
                 "link": "Link",
+                "selectToLink": "Select exercises to link",
                 "unknownError": "Unsuccessful due to an unknown error. Please contact an admin!",
                 "noCoursesError": "You do not have any LTI-enabled courses in Artemis yet. Please configure at least one course to use this feature.",
                 "learnMore": "Learn more about enabling LTI in your course.."

src/test/javascript/spec/component/lti/lti13-deep-linking.component.spec.ts

@@ -7,7 +7,7 @@ import { AccountService } from 'app/core/auth/account.service';
 import { SortService } from 'app/shared/service/sort.service';
 import { of, throwError } from 'rxjs';
 import { ArtemisTranslatePipe } from 'app/shared/pipes/artemis-translate.pipe';
-import { MockPipe, MockProvider } from 'ng-mocks';
+import { MockPipe } from 'ng-mocks';
 import { User } from 'app/core/user/user.model';
 import { Course } from 'app/entities/course.model';
 import { Exercise, ExerciseType } from 'app/entities/exercise.model';
@@ -27,6 +27,7 @@ describe('Lti13DeepLinkingComponent', () => {
     const courseManagementServiceMock = { findWithExercises: jest.fn() };
     const accountServiceMock = { identity: jest.fn(), getAuthenticationState: jest.fn() };
     const sortServiceMock = { sortByProperty: jest.fn() };
+    const alertServiceMock = { error: jest.fn(), addAlert: jest.fn() };
 
     const exercise1 = { id: 1, shortName: 'git', type: ExerciseType.PROGRAMMING } as Exercise;
     const exercise2 = { id: 2, shortName: 'test', type: ExerciseType.PROGRAMMING } as Exercise;
@@ -46,7 +47,7 @@ describe('Lti13DeepLinkingComponent', () => {
                 { provide: AccountService, useValue: accountServiceMock },
                 { provide: SortService, useValue: sortServiceMock },
                 { provide: SessionStorageService, useClass: MockSyncStorage },
-                MockProvider(AlertService),
+                { provide: AlertService, useValue: alertServiceMock },
             ],
         }).compileComponents();
         jest.spyOn(console, 'error').mockImplementation(() => {});
@@ -76,6 +77,16 @@ describe('Lti13DeepLinkingComponent', () => {
         expect(component.exercises).toContainAllValues(course.exercises!);
     }));
 
+    it('should alert user when no exercise is selected', () => {
+        component.selectedExercises = undefined;
+        component.sendDeepLinkRequest();
+        expect(alertServiceMock.error).toHaveBeenCalledWith('artemisApp.lti13.deepLinking.selectToLink');
+
+        component.selectedExercises = new Set();
+        component.sendDeepLinkRequest();
+        expect(alertServiceMock.error).toHaveBeenNthCalledWith(2, 'artemisApp.lti13.deepLinking.selectToLink');
+    });
+
     it('should navigate on init when user is authenticated', fakeAsync(() => {
         const redirectSpy = jest.spyOn(component, 'redirectUserToLoginThenTargetLink');
         accountServiceMock.identity.mockResolvedValue(undefined);