fix: handle broken thumbnails and incomplete uploads

- Implement automatic thumbnail regeneration for corrupted files
- Add validation middleware to check uploaded files before processing
- Improve error handling for "Premature end of input file" errors
- Delete and regenerate thumbnails when serving fails
- Add file integrity checks during upload process
- Better error reporting for failed uploads

This fixes the VipsJpeg errors and ensures reliable thumbnail generation.

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

backend/src/routes/adminPhotos.js

@@ -4,9 +4,10 @@ const path = require('path');
 const fs = require('fs').promises;
 const { db, logActivity } = require('../database/db');
 const { adminAuth } = require('../middleware/auth');
-const { generateThumbnail } = require('../services/imageProcessor');
+const { generateThumbnail, ensureThumbnail } = require('../services/imageProcessor');
 const { generatePhotoFilename } = require('../utils/filenameSanitizer');
 const { escapeLikePattern } = require('../utils/sqlSecurity');
+const { validateUploadedFiles } = require('../middleware/uploadValidation');
 const router = express.Router();
 
 // Get storage path from environment or default
@@ -106,7 +107,7 @@ router.post('/:eventId/upload', adminAuth, (req, res, next) => {
     }
     next();
   });
-}, validateUploadContent, async (req, res) => {
+}, validateUploadContent, validateUploadedFiles, async (req, res) => {
   try {
     const { eventId } = req.params;
     const { category_id } = req.body;
@@ -197,8 +198,14 @@ router.post('/:eventId/upload', adminAuth, (req, res, next) => {
             file.filename = newFilename;
             file.path = newPath;
             
-            // Generate thumbnail with new filename
-            const thumbnailPath = await generateThumbnail(file.path);
+            // Generate thumbnail with new filename (with better error handling)
+            let thumbnailPath = null;
+            try {
+              thumbnailPath = await generateThumbnail(file.path);
+            } catch (thumbError) {
+              console.error(`Thumbnail generation failed for ${file.filename}:`, thumbError.message);
+              // Continue without thumbnail rather than failing the whole upload
+            }
             
             // Calculate relative paths
             const storagePath = getStoragePath();
@@ -269,19 +276,23 @@ router.post('/:eventId/upload', adminAuth, (req, res, next) => {
       { type: 'admin', id: req.admin.id, name: req.admin.username }
     );
     
+    // Include any files that were invalid from the validation middleware
+    const totalInvalidFiles = (req.invalidFiles || []).concat(errors);
+    
     // Prepare response
+    const totalAttempted = req.files.length + (req.invalidFiles ? req.invalidFiles.length : 0);
     const response = {
       message: `Successfully uploaded ${uploadedPhotos.length} photos`,
       photos: uploadedPhotos,
-      totalFiles: req.files.length,
+      totalFiles: totalAttempted,
       successCount: uploadedPhotos.length,
-      failureCount: errors.length
+      failureCount: totalInvalidFiles.length
     };
     
     // Include error details if any files failed
-    if (errors.length > 0) {
-      response.errors = errors;
-      response.message = `Uploaded ${uploadedPhotos.length} of ${req.files.length} photos. ${errors.length} failed.`;
+    if (totalInvalidFiles.length > 0) {
+      response.errors = totalInvalidFiles;
+      response.message = `Uploaded ${uploadedPhotos.length} of ${totalAttempted} photos. ${totalInvalidFiles.length} failed.`;
     }
     
     res.json(response);
@@ -613,26 +624,24 @@ router.get('/:eventId/thumbnail/:photoId', adminAuth, async (req, res) => {
       .where({ id: photoId, event_id: eventId })
       .first();
     
-    if (!photo || !photo.thumbnail_path) {
-      console.error(`Thumbnail not found for photo ${photoId}, event ${eventId}`);
-      return res.status(404).json({ error: 'Thumbnail not found' });
+    if (!photo) {
+      console.error(`Photo not found: ${photoId}, event ${eventId}`);
+      return res.status(404).json({ error: 'Photo not found' });
+    }
+    
+    // Ensure thumbnail exists and is valid, regenerate if needed
+    const thumbnailPath = await ensureThumbnail(photo);
+    
+    if (!thumbnailPath) {
+      console.error(`Failed to generate thumbnail for photo ${photoId}`);
+      return res.status(404).json({ error: 'Thumbnail generation failed' });
     }
     
     const storagePath = getStoragePath();
-    const filePath = path.join(storagePath, photo.thumbnail_path);
-    
-    console.log(`Attempting to serve thumbnail: ${filePath}`);
-    
-    // Check if file exists
-    try {
-      await fs.access(filePath);
-    } catch (error) {
-      console.error(`Thumbnail file not found: ${filePath}`, error);
-      return res.status(404).json({ error: 'Thumbnail file not found' });
-    }
+    const filePath = path.join(storagePath, thumbnailPath);
     
     // Set appropriate headers
-    res.setHeader('Content-Type', `image/${path.extname(photo.thumbnail_path).slice(1)}`);
+    res.setHeader('Content-Type', 'image/jpeg'); // Thumbnails are always JPEG
     res.setHeader('Cache-Control', 'private, max-age=3600');
     res.setHeader('Cross-Origin-Resource-Policy', 'cross-origin');