Lectures: Allow drag and dropping of PDF pages

src/main/java/de/tum/cit/aet/artemis/lecture/repository/SlideRepository.java

@@ -20,10 +20,10 @@
 @Repository
 public interface SlideRepository extends ArtemisJpaRepository<Slide, String> {
 
-    Slide findSlideByAttachmentUnitIdAndSlideNumber(Long attachmentUnitId, Integer slideNumber);
-
     Slide findByAttachmentUnitIdAndId(Long attachmentUnitId, String id);
 
+    List<Slide> findAllByAttachmentUnitId(Long attachmentUnitId);
+
     /**
      * Find all slides that have a non-null hidden timestamp
      *

src/main/java/de/tum/cit/aet/artemis/lecture/service/AttachmentUnitService.java

@@ -105,10 +105,11 @@ public AttachmentUnit createAttachmentUnit(AttachmentUnit attachmentUnit, Attach
      * @param studentVersionFile     The student version of the original file.
      * @param keepFilename           Whether to keep the original filename or not.
      * @param hiddenPages            The hidden pages of attachment unit.
+     * @param pageOrder              The new order of the edited attachment unit
      * @return The updated attachment unit.
      */
     public AttachmentUnit updateAttachmentUnit(AttachmentUnit existingAttachmentUnit, AttachmentUnit updateUnit, Attachment updateAttachment, MultipartFile updateFile,
-            MultipartFile studentVersionFile, boolean keepFilename, String hiddenPages) {
+            MultipartFile studentVersionFile, boolean keepFilename, String hiddenPages, String pageOrder) {
         Set<CompetencyLectureUnitLink> existingCompetencyLinks = new HashSet<>(existingAttachmentUnit.getCompetencyLinks());
 
         existingAttachmentUnit.setDescription(updateUnit.getDescription());
@@ -136,7 +137,7 @@ public AttachmentUnit updateAttachmentUnit(AttachmentUnit existingAttachmentUnit
         if (updateFile != null) {
             // Split the updated file into single slides only if it is a pdf
             if (Objects.equals(FilenameUtils.getExtension(updateFile.getOriginalFilename()), "pdf")) {
-                slideSplitterService.splitAttachmentUnitIntoSingleSlides(savedAttachmentUnit, hiddenPages);
+                slideSplitterService.splitAttachmentUnitIntoSingleSlides(savedAttachmentUnit, hiddenPages, pageOrder);
             }
             if (pyrisWebhookService.isPresent() && irisSettingsRepository.isPresent()) {
                 pyrisWebhookService.get().autoUpdateAttachmentUnitsInPyris(savedAttachmentUnit.getLecture().getCourse().getId(), List.of(savedAttachmentUnit));

src/main/java/de/tum/cit/aet/artemis/lecture/service/SlideSplitterService.java

@@ -10,12 +10,12 @@
 import java.nio.file.Path;
 import java.sql.Timestamp;
 import java.time.Instant;
-import java.util.Collections;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
 import java.util.Objects;
 import java.util.Optional;
+import java.util.Set;
 import java.util.stream.Collectors;
 
 import javax.imageio.ImageIO;
@@ -75,22 +75,23 @@ public SlideSplitterService(FileService fileService, SlideRepository slideReposi
      */
     @Async
     public void splitAttachmentUnitIntoSingleSlides(AttachmentUnit attachmentUnit) {
-        splitAttachmentUnitIntoSingleSlides(attachmentUnit, null);
+        splitAttachmentUnitIntoSingleSlides(attachmentUnit, null, null);
     }
 
     /**
      * Splits an Attachment Unit file into single slides and saves them as PNG files asynchronously.
      *
      * @param attachmentUnit The attachment unit to which the slides belong.
      * @param hiddenPages    The hidden pages of the attachment unit.
+     * @param pageOrder      The page order of the attachment unit.
      */
     @Async
-    public void splitAttachmentUnitIntoSingleSlides(AttachmentUnit attachmentUnit, String hiddenPages) {
+    public void splitAttachmentUnitIntoSingleSlides(AttachmentUnit attachmentUnit, String hiddenPages, String pageOrder) {
         Path attachmentPath = FilePathService.actualPathForPublicPath(URI.create(attachmentUnit.getAttachment().getLink()));
         File file = attachmentPath.toFile();
         try (PDDocument document = Loader.loadPDF(file)) {
             String pdfFilename = file.getName();
-            splitAttachmentUnitIntoSingleSlides(document, attachmentUnit, pdfFilename, hiddenPages);
+            splitAttachmentUnitIntoSingleSlides(document, attachmentUnit, pdfFilename, hiddenPages, pageOrder);
         }
         catch (IOException e) {
             log.error("Error while splitting Attachment Unit {} into single slides", attachmentUnit.getId(), e);
@@ -106,7 +107,7 @@ public void splitAttachmentUnitIntoSingleSlides(AttachmentUnit attachmentUnit, S
      * @param pdfFilename    The name of the PDF file.
      */
     public void splitAttachmentUnitIntoSingleSlides(PDDocument document, AttachmentUnit attachmentUnit, String pdfFilename) {
-        splitAttachmentUnitIntoSingleSlides(document, attachmentUnit, pdfFilename, null);
+        splitAttachmentUnitIntoSingleSlides(document, attachmentUnit, pdfFilename, null, null);
     }
 
     /**
@@ -115,49 +116,58 @@ public void splitAttachmentUnitIntoSingleSlides(PDDocument document, AttachmentU
      * @param attachmentUnit The attachment unit to which the slides belong.
      * @param document       The PDF document that is already loaded.
      * @param pdfFilename    The name of the PDF file.
-     * @param hiddenPages    The hidden pages of the attachment unit.
+     * @param hiddenPages    The hidden pages information.
+     * @param pageOrder      The order of pages in the PDF.
      */
-    public void splitAttachmentUnitIntoSingleSlides(PDDocument document, AttachmentUnit attachmentUnit, String pdfFilename, String hiddenPages) {
-        log.debug("Splitting Attachment Unit file {} into single slides", attachmentUnit.getAttachment().getName());
+    public void splitAttachmentUnitIntoSingleSlides(PDDocument document, AttachmentUnit attachmentUnit, String pdfFilename, String hiddenPages, String pageOrder) {
+        log.debug("Processing slides for Attachment Unit {}", attachmentUnit.getAttachment().getName());
         try {
-            String fileNameWithOutExt = FilenameUtils.removeExtension(pdfFilename);
-            int numPages = document.getNumberOfPages();
-            PDFRenderer pdfRenderer = new PDFRenderer(document);
+            List<Map<String, Object>> pageOrderList = new ObjectMapper().readValue(pageOrder, new TypeReference<>() {
+            });
 
-            Map<Integer, Map<String, Object>> hiddenPagesData = Collections.emptyMap();
-            if (hiddenPages != null) {
-                List<Map<String, Object>> hiddenPagesList = new ObjectMapper().readValue(hiddenPages, new TypeReference<List<Map<String, Object>>>() {
+            Map<String, Map<String, Object>> hiddenPagesMap = new HashMap<>();
+            if (hiddenPages != null && !hiddenPages.isEmpty()) {
+                List<Map<String, Object>> hiddenPagesList = new ObjectMapper().readValue(hiddenPages, new TypeReference<>() {
                 });
-                hiddenPagesData = hiddenPagesList.stream().collect(Collectors.toMap(map -> (Integer) map.get("pageIndex"), map -> {
+
+                hiddenPagesMap = hiddenPagesList.stream().collect(Collectors.toMap(page -> (String) page.get("slideId"), page -> {
                     Map<String, Object> data = new HashMap<>();
-                    String dateStr = (String) map.get("date");
+                    String dateStr = (String) page.get("date");
                     data.put("date", Timestamp.from(Instant.parse(dateStr)));
 
-                    // Include exercise ID if it exists
-                    if (map.get("exerciseId") != null) {
-                        data.put("exerciseId", map.get("exerciseId"));
+                    if (page.get("exerciseId") != null) {
+                        data.put("exerciseId", page.get("exerciseId"));
                     }
                     return data;
                 }));
             }
 
-            for (int page = 0; page < numPages; page++) {
-                BufferedImage bufferedImage = pdfRenderer.renderImageWithDPI(page, 72, ImageType.RGB);
-                byte[] imageInByte = bufferedImageToByteArray(bufferedImage, "png");
-                int slideNumber = page + 1;
-                String filename = fileNameWithOutExt + "_" + attachmentUnit.getId() + "_Slide_" + slideNumber + ".png";
-                MultipartFile slideFile = fileService.convertByteArrayToMultipart(filename, ".png", imageInByte);
-                Path savePath = fileService.saveFile(slideFile, FilePathService.getAttachmentUnitFilePath().resolve(attachmentUnit.getId().toString()).resolve("slide")
-                        .resolve(String.valueOf(slideNumber)).resolve(filename));
-
-                Optional<Slide> existingSlideOpt = Optional.ofNullable(slideRepository.findSlideByAttachmentUnitIdAndSlideNumber(attachmentUnit.getId(), slideNumber));
-                Slide slide = existingSlideOpt.orElseGet(Slide::new);
-                slide.setSlideImagePath(FilePathService.publicPathForActualPath(savePath, (long) slideNumber).toString());
-                slide.setSlideNumber(slideNumber);
-                slide.setAttachmentUnit(attachmentUnit);
-
-                // Get the hidden data for this slide
-                Map<String, Object> hiddenData = hiddenPagesData.get(slideNumber);
+            List<Slide> existingSlides = slideRepository.findAllByAttachmentUnitId(attachmentUnit.getId());
+            Map<String, Slide> existingSlidesMap = existingSlides.stream().collect(Collectors.toMap(Slide::getId, slide -> slide));
+
+            PDFRenderer pdfRenderer = new PDFRenderer(document);
+            String fileNameWithOutExt = FilenameUtils.removeExtension(pdfFilename);
+
+            for (Map<String, Object> page : pageOrderList) {
+                String slideId = (String) page.get("slideId");
+                int order = ((Number) page.get("order")).intValue();
+                int pageIndex = ((Number) page.get("pageIndex")).intValue();
+
+                Slide slide;
+                boolean isNewSlide = false;
+
+                if (slideId.startsWith("temp_") || !existingSlidesMap.containsKey(slideId)) {
+                    isNewSlide = true;
+                    slide = new Slide();
+                    slide.setAttachmentUnit(attachmentUnit);
+                }
+                else {
+                    slide = existingSlidesMap.get(slideId);
+                }
+
+                slide.setSlideNumber(order);
+
+                Map<String, Object> hiddenData = hiddenPagesMap.get(slideId);
                 java.util.Date previousHiddenValue = slide.getHidden();
 
                 if (hiddenData != null && hiddenData.containsKey("date")) {
@@ -177,6 +187,20 @@ public void splitAttachmentUnitIntoSingleSlides(PDDocument document, AttachmentU
                     slide.setExercise(null);
                 }
 
+                if (isNewSlide) {
+                    int pdfPageIndex = pageIndex - 1;
+                    if (pdfPageIndex >= 0 && pdfPageIndex < document.getNumberOfPages()) {
+                        BufferedImage bufferedImage = pdfRenderer.renderImageWithDPI(pdfPageIndex, 72, ImageType.RGB);
+                        byte[] imageInByte = bufferedImageToByteArray(bufferedImage, "png");
+                        String filename = fileNameWithOutExt + "_" + attachmentUnit.getId() + "_Slide_" + order + ".png";
+                        MultipartFile slideFile = fileService.convertByteArrayToMultipart(filename, ".png", imageInByte);
+                        Path savePath = fileService.saveFile(slideFile, FilePathService.getAttachmentUnitFilePath().resolve(attachmentUnit.getId().toString()).resolve("slide")
+                                .resolve(String.valueOf(order)).resolve(filename));
+
+                        slide.setSlideImagePath(FilePathService.publicPathForActualPath(savePath, (long) order).toString());
+                    }
+                }
+
                 Slide savedSlide = slideRepository.save(slide);
 
                 // Schedule unhiding if the hidden date has changed
@@ -185,10 +209,20 @@ public void splitAttachmentUnitIntoSingleSlides(PDDocument document, AttachmentU
                     log.debug("Scheduled unhiding for slide ID {} at time {}", savedSlide.getId(), slide.getHidden());
                 }
             }
+
+            // Clean up slides that are no longer in the page order
+            Set<String> slideIdsInPageOrder = pageOrderList.stream().map(page -> (String) page.get("slideId")).collect(Collectors.toSet());
+
+            List<Slide> slidesToRemove = existingSlides.stream().filter(slide -> !slideIdsInPageOrder.contains(slide.getId())).toList();
+
+            if (!slidesToRemove.isEmpty()) {
+                slideRepository.deleteAll(slidesToRemove);
+                log.debug("Removed {} slides that are no longer in the page order", slidesToRemove.size());
+            }
         }
         catch (IOException e) {
-            log.error("Error while splitting Attachment Unit {} into single slides", attachmentUnit.getId(), e);
-            throw new InternalServerErrorException("Could not split Attachment Unit into single slides: " + e.getMessage());
+            log.error("Error while processing slides for Attachment Unit {}", attachmentUnit.getId(), e);
+            throw new InternalServerErrorException("Could not process slides: " + e.getMessage());
         }
     }
 

src/main/java/de/tum/cit/aet/artemis/lecture/web/AttachmentUnitResource.java

@@ -117,6 +117,7 @@ public ResponseEntity<AttachmentUnit> getAttachmentUnit(@PathVariable Long attac
      * @param attachment       the attachment with updated content
      * @param file             the optional file to upload
      * @param hiddenPages      the pages to be hidden in the attachment unit
+     * @param pageOrder        the new order of the edited attachment unit
      * @param studentVersion   the student version of the file to upload
      * @param keepFilename     specifies if the original filename should be kept or not
      * @param notificationText the text to be used for the notification. No notification will be sent if the parameter is not set
@@ -126,15 +127,15 @@ public ResponseEntity<AttachmentUnit> getAttachmentUnit(@PathVariable Long attac
     @EnforceAtLeastEditor
     public ResponseEntity<AttachmentUnit> updateAttachmentUnit(@PathVariable Long lectureId, @PathVariable Long attachmentUnitId, @RequestPart AttachmentUnit attachmentUnit,
             @RequestPart Attachment attachment, @RequestPart(required = false) MultipartFile file, @RequestPart(required = false) MultipartFile studentVersion,
-            @RequestPart(required = false) String hiddenPages, @RequestParam(defaultValue = "false") boolean keepFilename,
+            @RequestPart(required = false) String hiddenPages, @RequestPart(required = false) String pageOrder, @RequestParam(defaultValue = "false") boolean keepFilename,
             @RequestParam(value = "notificationText", required = false) String notificationText) {
         log.debug("REST request to update an attachment unit : {}", attachmentUnit);
         AttachmentUnit existingAttachmentUnit = attachmentUnitRepository.findWithSlidesAndCompetenciesByIdElseThrow(attachmentUnitId);
         checkAttachmentUnitCourseAndLecture(existingAttachmentUnit, lectureId);
         authorizationCheckService.checkHasAtLeastRoleInCourseElseThrow(Role.EDITOR, existingAttachmentUnit.getLecture().getCourse(), null);
 
         AttachmentUnit savedAttachmentUnit = attachmentUnitService.updateAttachmentUnit(existingAttachmentUnit, attachmentUnit, attachment, file, studentVersion, keepFilename,
-                hiddenPages);
+                hiddenPages, pageOrder);
 
         if (notificationText != null) {
             groupNotificationService.notifyStudentGroupAboutAttachmentChange(savedAttachmentUnit.getAttachment(), notificationText);

src/main/webapp/app/lecture/pdf-preview/pdf-preview-date-box/pdf-preview-date-box.component.html

@@ -2,9 +2,9 @@
     <div class="popover-title mb-2">
         <h5>
             @if (isMultiplePages()) {
-                <span jhiTranslate="artemisApp.attachment.pdfPreview.dateBox.hideMultiplePages" [translateValues]="{ param: pageIndicesSorted() }"></span>
+                <span jhiTranslate="artemisApp.attachment.pdfPreview.dateBox.hideMultiplePages" [translateValues]="{ param: pagesDisplay() }"></span>
             } @else {
-                <span jhiTranslate="artemisApp.attachment.pdfPreview.dateBox.hidePage" [translateValues]="{ param: pageIndices()! }"></span>
+                <span jhiTranslate="artemisApp.attachment.pdfPreview.dateBox.hidePage" [translateValues]="{ param: pagesDisplay() }"></span>
             }
         </h5>
     </div>

src/main/webapp/app/lecture/pdf-preview/pdf-preview-date-box/pdf-preview-date-box.component.ts

@@ -4,7 +4,7 @@ import { Course } from 'app/entities/course.model';
 import { Exercise, ExerciseType } from 'app/entities/exercise.model';
 import { CourseExerciseService } from 'app/exercises/shared/course-exercises/course-exercise.service';
 import dayjs from 'dayjs/esm';
-import { HiddenPage } from 'app/lecture/pdf-preview/pdf-preview.component';
+import { HiddenPage, OrderedPage } from 'app/lecture/pdf-preview/pdf-preview.component';
 import { AlertService } from 'app/core/util/alert.service';
 import { FontAwesomeModule } from '@fortawesome/angular-fontawesome';
 import { NgbTooltipModule } from '@ng-bootstrap/ng-bootstrap';
@@ -29,7 +29,7 @@ const FOREVER = dayjs('9999-12-31');
 export class PdfPreviewDateBoxComponent implements OnInit {
     // Inputs
     course = input<Course>();
-    pageIndices = input<number[]>([]);
+    selectedPages = input<OrderedPage[]>([]);
 
     // Signals
     calendarSelected = signal<boolean>(false);
@@ -39,25 +39,32 @@ export class PdfPreviewDateBoxComponent implements OnInit {
     categorizedExercises = signal<CategorizedExercise[]>([]);
     hideForever = signal<boolean>(false);
     selectedExercise = signal<Exercise | null>(null);
-    isMultiplePages = signal<boolean>(false);
 
     // Outputs
     hiddenPagesOutput = output<HiddenPage[]>();
     selectionCancelledOutput = output<boolean>();
 
     // Computed properties
-    pageIndicesSorted = computed(() => {
-        const indices = [...this.pageIndices()];
-        return indices.sort((a, b) => a - b).join(', ');
+    pagesDisplay = computed(() => {
+        const pages = this.selectedPages();
+
+        if (pages.length === 1) {
+            return `${pages[0].pageIndex}`;
+        }
+
+        return pages
+            .map((p) => p.pageIndex)
+            .sort()
+            .join(', ');
     });
+    isMultiplePages = computed(() => this.selectedPages().length > 1);
 
     // Injected services
     private readonly alertService = inject(AlertService);
     private readonly courseExerciseService = inject(CourseExerciseService);
 
     ngOnInit(): void {
         this.loadExercises();
-        this.isMultiplePages.set(this.pageIndices().length > 1);
     }
 
     /**
@@ -169,8 +176,8 @@ export class PdfPreviewDateBoxComponent implements OnInit {
             return;
         }
 
-        const hiddenPages: HiddenPage[] = this.pageIndices().map((pageIndex) => ({
-            pageIndex,
+        const hiddenPages: HiddenPage[] = this.selectedPages().map((page) => ({
+            slideId: page.slideId,
             date: selectedDate,
             exerciseId: this.selectedExercise()?.id ?? null,
         }));