Plagiarism checks: Improve file selection in comparison

src/main/webapp/app/exercises/shared/plagiarism/plagiarism-split-view/plagiarism-split-view.component.html

@@ -5,10 +5,24 @@
                 <jhi-modeling-submission-viewer [exercise]="exercise" [plagiarismSubmission]="getModelingSubmissionA()" [hideContent]="false" />
             }
             @if (isProgrammingOrTextExercise) {
-                <jhi-text-submission-viewer [exercise]="exercise" [matches]="matchesA" [plagiarismSubmission]="getTextSubmissionA()" [hideContent]="false" />
+                <jhi-text-submission-viewer
+                    [fileSelectedSubject]="this.fileSelectedSubject"
+                    [exercise]="exercise"
+                    [matches]="matchesA"
+                    [plagiarismSubmission]="getTextSubmissionA()"
+                    [isLockFilesEnabled]="isLockFilesEnabled"
+                    [hideContent]="false"
+                    [dropdownHoverSubject]="this.dropdownHoverSubject"
+                    [showFilesSubject]="this.showFilesSubject"
+                />
             }
         }
     </div>
+    <div class="split-pane-header-color">
+        <button class="btn btn-sm" (click)="toggleLockFiles()" [class.active]="isLockFilesEnabled" data-qa="lock-files-toggle-button">
+            <fa-icon [icon]="isLockFilesEnabled ? faLock : faUnlock" aria-label="Synchronize files while navigating on both sides"></fa-icon>
+        </button>
+    </div>
     <div class="plagiarism-split-pane" jhiPane>
         @if (plagiarismComparison) {
             @if (isModelingExercise) {
@@ -20,10 +34,14 @@
             }
             @if (isProgrammingOrTextExercise) {
                 <jhi-text-submission-viewer
+                    [fileSelectedSubject]="this.fileSelectedSubject"
                     [exercise]="exercise"
                     [matches]="matchesB"
                     [plagiarismSubmission]="getTextSubmissionB()"
+                    [isLockFilesEnabled]="isLockFilesEnabled"
                     [hideContent]="forStudent && dayjs(exercise.dueDate).isAfter(dayjs())"
+                    [dropdownHoverSubject]="this.dropdownHoverSubject"
+                    [showFilesSubject]="this.showFilesSubject"
                 />
             }
         }

src/main/webapp/app/exercises/shared/plagiarism/plagiarism-split-view/plagiarism-split-view.component.scss

@@ -19,3 +19,7 @@
         position: relative;
     }
 }
+
+.split-pane-header-color {
+    background-color: var(--bs-body-bg);
+}

src/main/webapp/app/exercises/shared/plagiarism/plagiarism-split-view/plagiarism-split-view.component.ts

@@ -1,4 +1,4 @@
-import { AfterViewInit, Component, Directive, ElementRef, Input, OnChanges, OnInit, QueryList, SimpleChanges, ViewChildren } from '@angular/core';
+import { AfterViewInit, Component, Directive, ElementRef, Input, OnChanges, OnDestroy, OnInit, QueryList, SimpleChanges, ViewChildren } from '@angular/core';
 import * as Split from 'split.js';
 import { Subject } from 'rxjs';
 import { PlagiarismComparison } from 'app/exercises/shared/plagiarism/types/PlagiarismComparison';
@@ -10,6 +10,8 @@ import { PlagiarismCasesService } from 'app/course/plagiarism-cases/shared/plagi
 import { HttpResponse } from '@angular/common/http';
 import { SimpleMatch } from 'app/exercises/shared/plagiarism/types/PlagiarismMatch';
 import dayjs from 'dayjs/esm';
+import { TextPlagiarismFileElement } from 'app/exercises/shared/plagiarism/types/text/TextPlagiarismFileElement';
+import { IconDefinition, faLock, faUnlock } from '@fortawesome/free-solid-svg-icons';
 
 @Directive({ selector: '[jhiPane]' })
 export class SplitPaneDirective {
@@ -21,7 +23,7 @@ export class SplitPaneDirective {
     styleUrls: ['./plagiarism-split-view.component.scss'],
     templateUrl: './plagiarism-split-view.component.html',
 })
-export class PlagiarismSplitViewComponent implements AfterViewInit, OnChanges, OnInit {
+export class PlagiarismSplitViewComponent implements AfterViewInit, OnChanges, OnInit, OnDestroy {
     @Input() comparison: PlagiarismComparison<TextSubmissionElement | ModelingSubmissionElement>;
     @Input() exercise: Exercise;
     @Input() splitControlSubject: Subject<string>;
@@ -31,6 +33,9 @@ export class PlagiarismSplitViewComponent implements AfterViewInit, OnChanges, O
     @ViewChildren(SplitPaneDirective) panes!: QueryList<SplitPaneDirective>;
 
     plagiarismComparison: PlagiarismComparison<TextSubmissionElement | ModelingSubmissionElement>;
+    fileSelectedSubject = new Subject<TextPlagiarismFileElement>();
+    showFilesSubject = new Subject<boolean>();
+    dropdownHoverSubject = new Subject<TextPlagiarismFileElement>();
 
     public split: Split.Instance;
 
@@ -39,13 +44,16 @@ export class PlagiarismSplitViewComponent implements AfterViewInit, OnChanges, O
 
     public matchesA: Map<string, FromToElement[]>;
     public matchesB: Map<string, FromToElement[]>;
+    isLockFilesEnabled = false;
 
     readonly dayjs = dayjs;
+    protected readonly faLock: IconDefinition = faLock;
+    protected readonly faUnlock: IconDefinition = faUnlock;
 
     constructor(private plagiarismCasesService: PlagiarismCasesService) {}
 
     /**
-     * Initialize third party libs inside this lifecycle hook.
+     * Initialize third-party libraries inside this lifecycle hook.
      */
     ngAfterViewInit(): void {
         const paneElements = this.panes.map((pane: SplitPaneDirective) => pane.elementRef.nativeElement);
@@ -84,6 +92,12 @@ export class PlagiarismSplitViewComponent implements AfterViewInit, OnChanges, O
         }
     }
 
+    ngOnDestroy() {
+        this.fileSelectedSubject.complete();
+        this.showFilesSubject.complete();
+        this.dropdownHoverSubject.complete();
+    }
+
     /**
      * Swaps fields of A with fields of B in-place.
      * More specifically, swaps submissionA with submissionB and startA with startB in matches.
@@ -177,4 +191,11 @@ export class PlagiarismSplitViewComponent implements AfterViewInit, OnChanges, O
             }
         }
     }
+
+    /**
+     * Toggles the state of file locking and emits the new state to the parent component.
+     */
+    toggleLockFiles() {
+        this.isLockFilesEnabled = !this.isLockFilesEnabled;
+    }
 }

src/main/webapp/app/exercises/shared/plagiarism/plagiarism-split-view/split-pane-header/split-pane-header.component.html

@@ -1,5 +1,5 @@
 <div class="split-pane-header" ngbDropdown>
-    <div class="split-pane-header-top" data-toggle="dropdown" [ngClass]="{ active: showFiles, clickable: hasFiles() }" (click)="toggleShowFiles()">
+    <div class="split-pane-header-top" data-toggle="dropdown" [ngClass]="{ active: showFiles, clickable: hasFiles() }" (click)="toggleShowFiles(true)">
         @if (hasActiveFile()) {
             <div class="split-pane-header-file-name">
                 <fa-icon class="file-arrow-down" [icon]="faChevronDown" />
@@ -9,9 +9,15 @@
         <div>{{ studentLogin || ('artemisApp.plagiarism.unknownStudent' | artemisTranslate) }}</div>
     </div>
     @if (showFiles) {
-        <ul class="split-pane-header-files">
+        <ul (mouseleave)="toggleShowFiles(true, false)" class="split-pane-header-files">
             @for (file of files; track file; let idx = $index) {
-                <li class="split-pane-header-file" ngbDropdownItem (click)="handleFileSelect(file, idx)">
+                <li
+                    class="split-pane-header-file"
+                    ngbDropdownItem
+                    (mouseenter)="triggerMouseEnter(file, idx)"
+                    (click)="handleFileSelect(file, idx, true)"
+                    [ngClass]="{ hover: idx === hoveredFileIndex }"
+                >
                     <span [class.split-pane-header-file-with-match]="file.hasMatch">{{ file.file }}</span>
                 </li>
             }

src/main/webapp/app/exercises/shared/plagiarism/plagiarism-split-view/split-pane-header/split-pane-header.component.scss

@@ -50,3 +50,7 @@
         overflow: scroll;
     }
 }
+
+.dropdown-item.hover {
+    background-color: var(--data-table-dropdown-item-selected-background-color);
+}

src/main/webapp/app/exercises/shared/plagiarism/plagiarism-split-view/split-pane-header/split-pane-header.component.ts

@@ -1,5 +1,7 @@
-import { Component, EventEmitter, Input, OnChanges, Output, SimpleChanges } from '@angular/core';
+import { Component, EventEmitter, Input, OnChanges, OnDestroy, OnInit, Output, SimpleChanges, input } from '@angular/core';
 import { faChevronDown } from '@fortawesome/free-solid-svg-icons';
+import { Subject, Subscription } from 'rxjs';
+import { TextPlagiarismFileElement } from 'app/exercises/shared/plagiarism/types/text/TextPlagiarismFileElement';
 
 /**
  * A file name that additionally stores if a plagiarism match has been found for it.
@@ -14,16 +16,84 @@ export type FileWithHasMatch = {
     templateUrl: './split-pane-header.component.html',
     styleUrls: ['./split-pane-header.component.scss'],
 })
-export class SplitPaneHeaderComponent implements OnChanges {
+export class SplitPaneHeaderComponent implements OnChanges, OnInit, OnDestroy {
     @Input() files: FileWithHasMatch[];
     @Input() studentLogin: string;
+    fileSelectedSubject = input<Subject<TextPlagiarismFileElement>>();
+    isLockFilesEnabled = input<boolean>();
+    showFilesSubject = input<Subject<boolean>>();
+    dropdownHoverSubject = input<Subject<TextPlagiarismFileElement>>();
+
     @Output() selectFile = new EventEmitter<string>();
 
     public showFiles = false;
     public activeFileIndex = 0;
 
+    private fileSelectSubscription?: Subscription;
+    private showFilesSubscription?: Subscription;
+    private dropdownHoverSubscription?: Subscription;
+
     // Icons
     faChevronDown = faChevronDown;
+    hoveredFileIndex: number;
+
+    ngOnInit(): void {
+        this.subscribeToFileSelection();
+        this.subscribeToShowFiles();
+        this.subscribeToDropdownHover();
+    }
+
+    /**
+     * subscribes to listening onto file changes in component instance
+     * @private helper method
+     */
+    private subscribeToFileSelection(): void {
+        this.fileSelectSubscription = this.fileSelectedSubject()!.subscribe((textPlagiarismElement) => {
+            if (this.isLockFilesEnabled()) {
+                this.handleLockedFileSelection(textPlagiarismElement.file, textPlagiarismElement.idx);
+            }
+        });
+    }
+
+    private handleLockedFileSelection(file: FileWithHasMatch, idx: number): void {
+        const index = this.files[idx]?.file === file.file ? idx : this.getIndexOf(file);
+
+        if (index >= 0) {
+            this.handleFileSelect(file, index, false);
+        } else {
+            this.showFiles = false;
+        }
+    }
+
+    /**
+     * subscribes to listening onto dropdown toggle in component instance
+     * @private helper method
+     */
+    private subscribeToShowFiles(): void {
+        this.showFilesSubscription = this.showFilesSubject()?.subscribe((showFiles) => {
+            if (this.isLockFilesEnabled()! || (!this.isLockFilesEnabled()! && !showFiles)) {
+                this.toggleShowFiles(false, showFiles);
+            }
+        });
+    }
+
+    /**
+     * subscribes to listening onto mouse enter changes in dropdown in component instance
+     * @private helper method
+     */
+    private subscribeToDropdownHover(): void {
+        this.dropdownHoverSubscription = this.dropdownHoverSubject()?.subscribe((textPlagiarismElement) => {
+            if (this.isLockFilesEnabled()) {
+                this.handleDropdownHover(textPlagiarismElement.file, textPlagiarismElement.idx);
+            }
+        });
+    }
+
+    private handleDropdownHover(file: FileWithHasMatch, idx: number): void {
+        const index = this.files[idx]?.file === file.file ? idx : this.getIndexOf(file);
+
+        this.hoveredFileIndex = index >= 0 ? index : -1;
+    }
 
     ngOnChanges(changes: SimpleChanges) {
         if (changes.files) {
@@ -37,6 +107,12 @@ export class SplitPaneHeaderComponent implements OnChanges {
         }
     }
 
+    ngOnDestroy(): void {
+        this.fileSelectSubscription?.unsubscribe();
+        this.showFilesSubscription?.unsubscribe();
+        this.dropdownHoverSubscription?.unsubscribe();
+    }
+
     hasActiveFile(): boolean {
         return this.hasFiles() && this.activeFileIndex < this.files.length;
     }
@@ -45,19 +121,54 @@ export class SplitPaneHeaderComponent implements OnChanges {
         return this.files[this.activeFileIndex].file;
     }
 
-    handleFileSelect(file: FileWithHasMatch, idx: number): void {
+    /**
+     * handles selection of file from dropdown, propagates change to fileslectionsubject component for lock sync
+     * @param file to be selected
+     * @param idx index of the file from the dropdown
+     * @param propagateChanges propagate changes to listeners subscribed to fileSelectedSubject
+     */
+    handleFileSelect(file: FileWithHasMatch, idx: number, propagateChanges: boolean): void {
+        if (propagateChanges) {
+            this.fileSelectedSubject()!.next({ idx: idx, file: file });
+            file.hasMatch = true;
+        }
         this.activeFileIndex = idx;
         this.showFiles = false;
         this.selectFile.emit(file.file);
     }
 
     hasFiles(): boolean {
-        return this.files && this.files.length > 0;
+        return !!this.files?.length;
     }
 
-    toggleShowFiles(): void {
+    /**
+     * Toggles the dropdown visibility and optionally propagates changes to the parent component.
+     * @param showFiles Optional toggle status; if undefined, the status will be toggled.
+     * @param propagateChanges Whether to propagate the change to the parent component.
+     */
+    toggleShowFiles(propagateChanges: boolean, showFiles?: boolean): void {
         if (this.hasFiles()) {
-            this.showFiles = !this.showFiles;
+            this.showFiles = showFiles !== undefined ? showFiles : !this.showFiles;
+
+            if (propagateChanges) {
+                this.showFilesSubject()!.next(this.showFiles);
+            }
         }
     }
+
+    triggerMouseEnter(file: FileWithHasMatch, idx: number) {
+        const subject = this.dropdownHoverSubject();
+        if (subject) {
+            subject.next({ idx, file });
+        }
+    }
+
+    /**
+     * gets index of the file if it exists
+     * @param file The file to look up.
+     * @returns index if found, -1 otherwise
+     */
+    private getIndexOf(file: FileWithHasMatch): number {
+        return this.files.findIndex((f) => f.file === file.file);
+    }
 }

src/main/webapp/app/exercises/shared/plagiarism/plagiarism-split-view/text-submission-viewer/text-submission-viewer.component.html

@@ -1,4 +1,12 @@
-<jhi-split-pane-header [files]="files" (selectFile)="handleFileSelect($event)" studentLogin="{{ plagiarismSubmission?.studentLogin }}" />
+<jhi-split-pane-header
+    [files]="files"
+    [isLockFilesEnabled]="this.isLockFilesEnabled"
+    [fileSelectedSubject]="fileSelectedSubject"
+    (selectFile)="handleFileSelect($event)"
+    [showFilesSubject]="showFilesSubject"
+    [dropdownHoverSubject]="dropdownHoverSubject"
+    studentLogin="{{ plagiarismSubmission?.studentLogin }}"
+/>
 @if (cannotLoadFiles) {
     <div class="text-submission-viewer text-warning">
         <div class="text-submission-viewer-warning">

src/main/webapp/app/exercises/shared/plagiarism/plagiarism-split-view/text-submission-viewer/text-submission-viewer.component.ts

@@ -12,6 +12,8 @@ import { FileWithHasMatch } from 'app/exercises/shared/plagiarism/plagiarism-spl
 import { escape } from 'lodash-es';
 import { faExclamationTriangle } from '@fortawesome/free-solid-svg-icons';
 import { TEXT_FILE_EXTENSIONS } from 'app/shared/constants/file-extensions.constants';
+import { Subject } from 'rxjs';
+import { TextPlagiarismFileElement } from 'app/exercises/shared/plagiarism/types/text/TextPlagiarismFileElement';
 
 type FilesWithType = { [p: string]: FileType };
 
@@ -26,6 +28,10 @@ export class TextSubmissionViewerComponent implements OnChanges {
     @Input() matches: Map<string, FromToElement[]>;
     @Input() plagiarismSubmission: PlagiarismSubmission<TextSubmissionElement>;
     @Input() hideContent: boolean;
+    @Input() fileSelectedSubject!: Subject<TextPlagiarismFileElement>;
+    @Input() isLockFilesEnabled: boolean;
+    @Input() showFilesSubject!: Subject<boolean>;
+    @Input() dropdownHoverSubject!: Subject<TextPlagiarismFileElement>;
 
     /**
      * Name of the currently selected file.

src/main/webapp/app/exercises/shared/plagiarism/types/text/TextPlagiarismFileElement.ts

@@ -0,0 +1,6 @@
+import { FileWithHasMatch } from 'app/exercises/shared/plagiarism/plagiarism-split-view/split-pane-header/split-pane-header.component';
+
+export interface TextPlagiarismFileElement {
+    idx: number;
+    file: FileWithHasMatch;
+}

src/test/javascript/spec/component/plagiarism/plagiarism-header.component.spec.ts

@@ -13,6 +13,8 @@ import { HttpResponse } from '@angular/common/http';
 import { NgbModal } from '@ng-bootstrap/ng-bootstrap';
 import { MockNgbModalService } from '../../helpers/mocks/service/mock-ngb-modal.service';
 import { ButtonComponent } from 'app/shared/components/button.component';
+import { MockDirective } from 'ng-mocks';
+import { TranslateDirective } from 'app/shared/language/translate.directive';
 
 describe('Plagiarism Header Component', () => {
     let comp: PlagiarismHeaderComponent;
@@ -22,7 +24,7 @@ describe('Plagiarism Header Component', () => {
     beforeEach(() => {
         TestBed.configureTestingModule({
             imports: [ArtemisTestModule, TranslateTestingModule],
-            declarations: [PlagiarismHeaderComponent],
+            declarations: [PlagiarismHeaderComponent, MockDirective(TranslateDirective)],
             providers: [
                 { provide: TranslateService, useClass: MockTranslateService },
                 { provide: NgbModal, useClass: MockNgbModalService },

src/test/javascript/spec/component/plagiarism/plagiarism-split-view.component.spec.ts

@@ -170,7 +170,7 @@ describe('Plagiarism Split View Component', () => {
     });
 
     it('should parse text matches', () => {
-        jest.spyOn(comp, 'mapMatchesToElements').mockReturnValue(new Map());
+        jest.spyOn(comp, 'mapMatchesToElements').mockReturnValue(new Map<string, FromToElement[]>());
 
         const matches: PlagiarismMatch[] = [
             { startA: 0, startB: 0, length: 5 },