Refactor VocabService to improve boolean parameter handling and enhance debugging

- Updated VocabService to convert string parameters for course retrieval into booleans, ensuring accurate filtering based on user input.
- Added detailed debug logging to track the state of query conditions and the final WHERE clause, aiding in troubleshooting and performance analysis.
- Improved comments for clarity on the logic and implications of the changes made.

backend/services/vocabService.js

@@ -563,20 +563,24 @@ export default class VocabService {
   async getCourses(hashedUserId, { includePublic = true, includeOwn = true, languageId, nativeLanguageId, search } = {}) {
     const user = await this._getUserByHashedId(hashedUserId);
 
+    // Konvertiere String-Parameter zu Booleans
+    const includePublicBool = includePublic === 'true' || includePublic === true;
+    const includeOwnBool = includeOwn === 'true' || includeOwn === true;
+
     const where = {};
     const andConditions = [];
     
     // Zugriffsbedingungen
-    if (includeOwn && includePublic) {
+    if (includeOwnBool && includePublicBool) {
       andConditions.push({
         [Op.or]: [
           { ownerUserId: user.id },
           { isPublic: true }
         ]
       });
-    } else if (includeOwn) {
+    } else if (includeOwnBool) {
       where.ownerUserId = user.id;
-    } else if (includePublic) {
+    } else if (includePublicBool) {
       where.isPublic = true;
     }
 
@@ -608,9 +612,19 @@ export default class VocabService {
     // Kombiniere alle AND-Bedingungen
     // Wenn sowohl andConditions als auch direkte where-Eigenschaften existieren,
     // müssen sie kombiniert werden
+    const directWhereProps = Object.keys(where).filter(key => key !== Op.and && key !== Op.or);
+    
+    // Debug: Prüfe, ob direkte Eigenschaften gesetzt wurden
+    console.log(`[getCourses] Debug - Vor Kombination:`, {
+      directWhereProps,
+      whereKeys: Object.keys(where),
+      andConditionsLength: andConditions.length,
+      languageId,
+      nativeLanguageId
+    });
+    
     if (andConditions.length > 0) {
       // Wenn where bereits direkte Eigenschaften hat, füge sie zu andConditions hinzu
-      const directWhereProps = Object.keys(where).filter(key => key !== Op.and && key !== Op.or);
       if (directWhereProps.length > 0) {
         const directWhere = {};
         for (const key of directWhereProps) {
@@ -618,9 +632,15 @@ export default class VocabService {
           delete where[key];
         }
         andConditions.push(directWhere);
+        console.log(`[getCourses] Debug - Direkte Eigenschaften zu andConditions hinzugefügt:`, directWhere);
       }
       where[Op.and] = andConditions;
+      console.log(`[getCourses] Debug - Finale andConditions:`, JSON.stringify(andConditions, null, 2));
     }
+    // Wenn nur direkte Eigenschaften existieren (undConditions.length === 0),
+    // bleiben sie in where (nichts zu tun, sie sind bereits dort)
+    
+    console.log(`[getCourses] Debug - Finale WHERE-Klausel:`, JSON.stringify(where, null, 2));
 
     const courses = await VocabCourse.findAll({
       where,
@@ -633,9 +653,12 @@ export default class VocabService {
       languageId,
       nativeLanguageId,
       search,
-      where: JSON.stringify(where, null, 2),
-      includePublic,
-      includeOwn
+      whereBefore: JSON.stringify(where, null, 2),
+      includePublic: includePublicBool,
+      includeOwn: includeOwnBool,
+      andConditionsLength: andConditions.length,
+      directWherePropsBefore: Object.keys(where).filter(key => key !== Op.and && key !== Op.or),
+      whereAfter: JSON.stringify(where, null, 2)
     });
 
     const coursesData = courses.map(c => c.get({ plain: true }));