feat(VocabService, VocabCourseView): enhance SRS item retrieval and UI integration

- Updated VocabService to calculate total due count for spaced repetition system (SRS) items, improving data handling for user queries.
- Modified VocabCourseView to incorporate total due count in the UI, ensuring accurate display of SRS item statistics.
- Enhanced error handling and data validation for SRS due items, improving overall reliability and user experience.

backend/services/vocabService.js

@@ -1801,14 +1801,16 @@ export default class VocabService {
 
     const limit = this._clampInteger(query?.limit, { min: 1, max: 100, fallback: 30 });
     const now = new Date();
+    const dueWhere = {
+      userId: user.id,
+      courseId: Number(course.id),
+      nextDueAt: {
+        [Op.lte]: now
+      }
+    };
+    const totalDueCount = await VocabSrsItem.count({ where: dueWhere });
     const rows = await VocabSrsItem.findAll({
-      where: {
-        userId: user.id,
-        courseId: Number(course.id),
-        nextDueAt: {
-          [Op.lte]: now
-        }
-      },
+      where: dueWhere,
       order: [
         ['nextDueAt', 'ASC'],
         ['wrongCount', 'DESC'],
@@ -1821,6 +1823,8 @@ export default class VocabService {
       courseId: course.id,
       dueAt: now.toISOString(),
       count: rows.length,
+      totalDueCount,
+      limit,
       items: rows.map((item) => ({
         itemKey: item.itemKey,
         courseId: item.courseId,

frontend/src/views/social/VocabCourseView.vue

@@ -341,6 +341,7 @@ export default {
       progress: [],
       chapters: [],
       srsDueItems: [],
+      srsDueTotal: 0,
       srsLoading: false,
       showAddLessonDialog: false,
       assistantSettings: null,
@@ -384,6 +385,9 @@ export default {
       return this.currentLesson?.pedagogy?.blockNumber || null;
     },
     srsDueCount() {
+      if (Number.isFinite(Number(this.srsDueTotal)) && Number(this.srsDueTotal) > 0) {
+        return Number(this.srsDueTotal);
+      }
       return Array.isArray(this.srsDueItems) ? this.srsDueItems.length : 0;
     },
     dueReviewLessons() {
@@ -553,9 +557,11 @@ export default {
           params: { limit: 40 }
         });
         this.srsDueItems = Array.isArray(data?.items) ? data.items : [];
+        this.srsDueTotal = Number.isFinite(Number(data?.totalDueCount)) ? Number(data.totalDueCount) : this.srsDueItems.length;
       } catch (e) {
         console.warn('Konnte SRS-Fälligkeiten nicht laden:', e);
         this.srsDueItems = [];
+        this.srsDueTotal = 0;
       } finally {
         this.srsLoading = false;
       }