Fix of the edeting funktion in the Library Module

Web/app.py

@@ -9376,17 +9376,137 @@ def search_word(word):
     except Exception as e:
         return jsonify({"success": False, "response": str(e)})
 
+def _fetch_from_google_books(clean_isbn):
+    """Source 1: Google Books API (Free, No Key required for basic use)"""
+    try:
+        url = f"https://www.googleapis.com/books/v1/volumes?q=isbn:{clean_isbn}"
+        response = requests.get(url, timeout=5)
+        if response.status_code != 200:
+            return None
+        
+        data = response.json()
+        if data.get('totalItems', 0) > 0 and data.get('items'):
+            book_info = data['items'][0].get('volumeInfo', {})
+            sale_info = data['items'][0].get('saleInfo', {})
+
+            price = None
+            retail_price = sale_info.get('retailPrice', {})
+            list_price = sale_info.get('listPrice', {})
+            if retail_price and 'amount' in retail_price:
+                price = f"{retail_price['amount']} {retail_price.get('currencyCode', '€')}"
+            elif list_price and 'amount' in list_price:
+                price = f"{list_price['amount']} {list_price.get('currencyCode', '€')}"
+
+            thumbnail = book_info.get('imageLinks', {}).get('thumbnail', '')
+            if thumbnail:
+                thumbnail = thumbnail.replace('http:', 'https:')
+
+            return {
+                "title": book_info.get('title', 'Unknown Title'),
+                "authors": ', '.join(book_info.get('authors', ['Unknown Author'])),
+                "publisher": book_info.get('publisher', 'Unknown Publisher'),
+                "publishedDate": book_info.get('publishedDate', 'Unknown Date'),
+                "description": book_info.get('description', 'Keine Beschreibung verfügbar'),
+                "pageCount": book_info.get('pageCount', 'Unknown'),
+                "price": price,
+                "thumbnail": thumbnail,
+                "source": "google-books"
+            }
+    except Exception as e:
+        print(f"Google Books error: {e}")
+    return None
+
+
+def _fetch_from_lobid_germany(clean_isbn):
+    """
+    Source 2: Lobid.org (hbz Network)
+    The ultimate free, keyless fallback for German Schoolbooks and DACH literature.
+    """
+    try:
+        url = f"https://lobid.org/resources?q=isbn:{clean_isbn}&format=json"
+        response = requests.get(url, timeout=5)
+        if response.status_code != 200:
+            return None
+            
+        data = response.json()
+        if 'member' in data and len(data['member']) > 0:
+            book = data['member'][0]
+            
+            # Extract Authors (Lobid uses a nested contribution array)
+            authors = []
+            for contrib in book.get('contribution', []):
+                if 'agent' in contrib and 'label' in contrib['agent']:
+                    authors.append(contrib['agent']['label'])
+            
+            # Extract Publishers
+            publishers = []
+            for pub in book.get('publication', []):
+                if 'publishedBy' in pub:
+                    # sometimes publishedBy is a list, sometimes a string
+                    pub_data = pub['publishedBy']
+                    if isinstance(pub_data, list):
+                        publishers.extend(pub_data)
+                    else:
+                        publishers.append(pub_data)
+            
+            # Extract Date
+            pub_date = 'Unknown Date'
+            if book.get('publication'):
+                pub_date = book['publication'][0].get('startDate', 'Unknown Date')
+                
+            # Extract Pages
+            pages = book.get('extent', ['Unknown'])[0] if 'extent' in book else 'Unknown'
+            
+            return {
+                "title": book.get('title', 'Unknown Title'),
+                "authors": ', '.join(authors) if authors else 'Unknown Author',
+                "publisher": ', '.join(publishers) if publishers else 'Unknown Publisher',
+                "publishedDate": str(pub_date),
+                "description": 'Keine Beschreibung verfügbar (Schulbuch / Fachliteratur)',
+                "pageCount": pages,
+                "price": None,
+                "thumbnail": "", # Lobid rarely has covers, we will fallback to OpenLibrary cover below
+                "source": "lobid-germany"
+            }
+    except Exception as e:
+        print(f"Lobid error: {e}")
+    return None
+
+
+def _fetch_from_open_library(clean_isbn):
+    """Source 3: Open Library Search API (Free, No Key required)"""
+    try:
+        url = f"https://openlibrary.org/search.json?isbn={clean_isbn}"
+        response = requests.get(url, timeout=5)
+        if response.status_code != 200:
+            return None
+            
+        data = response.json()
+        if data.get('numFound', 0) > 0 and data.get('docs'):
+            book_info = data['docs'][0]
+            
+            return {
+                "title": book_info.get('title', 'Unknown Title'),
+                "authors": ', '.join(book_info.get('author_name', ['Unknown Author'])),
+                "publisher": ', '.join(book_info.get('publisher', ['Unknown Publisher'])),
+                "publishedDate": str(book_info.get('publish_date', ['Unknown Date'])[0]),
+                "description": 'Keine Beschreibung verfügbar',
+                "pageCount": book_info.get('number_of_pages_median', 'Unknown'),
+                "price": None,
+                "thumbnail": f"https://covers.openlibrary.org/b/isbn/{clean_isbn}-L.jpg",
+                "source": "openlibrary"
+            }
+    except Exception as e:
+        print(f"OpenLibrary Search error: {e}")
+    return None
+
 @app.route('/fetch_book_info/<isbn>')
 def fetch_book_info(isbn):
     """
-    API endpoint to fetch book information by ISBN using Google Books API
-    
-    Args:
-        isbn (str): ISBN to look up
-        
-    Returns:
-        dict: Book information or error message
+    API endpoint to fetch book information by ISBN using multiple open sources.
+    Optimized for global literature AND German educational books.
     """
+    # Authorization Checks
     if 'username' not in session or not us.check_admin(session['username']):
         return jsonify({"error": "Not authorized"}), 403
 
@@ -9394,79 +9514,33 @@ def fetch_book_info(isbn):
         return jsonify({"error": "Bibliotheks-Modul ist deaktiviert."}), 403
 
     try:
+        # Validation
         clean_isbn = normalize_and_validate_isbn(isbn)
         if not clean_isbn:
             return jsonify({"error": "Ungültige ISBN. Bitte ISBN-10 oder ISBN-13 verwenden."}), 400
 
-        # First source: Google Books
-        response = requests.get(
-            f"https://www.googleapis.com/books/v1/volumes?q=isbn:{clean_isbn}",
-            timeout=10
-        )
+        # Define the Provider Chain (Order matters: General -> German/School -> Global Fallback)
+        providers = [
+            _fetch_from_google_books,
+            _fetch_from_lobid_germany,
+            _fetch_from_open_library
+        ]
 
-        if response.status_code == 200:
-            data = response.json()
-            if data.get('totalItems', 0) > 0 and data.get('items'):
-                book_info = data['items'][0].get('volumeInfo', {})
-                sale_info = data['items'][0].get('saleInfo', {})
-
-                price = None
-                retail_price = sale_info.get('retailPrice', {})
-                list_price = sale_info.get('listPrice', {})
-                if retail_price and 'amount' in retail_price:
-                    price = f"{retail_price['amount']} {retail_price.get('currencyCode', '€')}"
-                elif list_price and 'amount' in list_price:
-                    price = f"{list_price['amount']} {list_price.get('currencyCode', '€')}"
-
-                thumbnail = book_info.get('imageLinks', {}).get('thumbnail', '')
-                if thumbnail:
-                    thumbnail = thumbnail.replace('http:', 'https:')
-
-                return jsonify({
-                    "title": book_info.get('title', 'Unknown Title'),
-                    "authors": ', '.join(book_info.get('authors', ['Unknown Author'])),
-                    "publisher": book_info.get('publisher', 'Unknown Publisher'),
-                    "publishedDate": book_info.get('publishedDate', 'Unknown Date'),
-                    "description": book_info.get('description', 'No description available'),
-                    "pageCount": book_info.get('pageCount', 'Unknown'),
-                    "price": price,
-                    "thumbnail": thumbnail,
-                    "isbn": clean_isbn,
-                    "source": "google-books"
-                })
-
-        # Fallback: OpenLibrary
-        ol_response = requests.get(
-            f"https://openlibrary.org/isbn/{clean_isbn}.json",
-            timeout=10
-        )
-        if ol_response.status_code == 200:
-            ol_data = ol_response.json()
-            author_names = []
-            for author_ref in ol_data.get('authors', []):
-                key = author_ref.get('key')
-                if not key:
-                    continue
-                try:
-                    author_resp = requests.get(f"https://openlibrary.org{key}.json", timeout=8)
-                    if author_resp.status_code == 200:
-                        author_names.append(author_resp.json().get('name'))
-                except Exception:
-                    continue
-
-            return jsonify({
-                "title": ol_data.get('title', 'Unknown Title'),
-                "authors": ', '.join([a for a in author_names if a]) if author_names else 'Unknown Author',
-                "publisher": ', '.join(ol_data.get('publishers', [])) if ol_data.get('publishers') else 'Unknown Publisher',
-                "publishedDate": ol_data.get('publish_date', 'Unknown Date'),
-                "description": (ol_data.get('description', {}).get('value') if isinstance(ol_data.get('description'), dict) else ol_data.get('description')) or 'No description available',
-                "pageCount": ol_data.get('number_of_pages', 'Unknown'),
-                "price": None,
-                "thumbnail": f"https://covers.openlibrary.org/b/isbn/{clean_isbn}-L.jpg",
-                "isbn": clean_isbn,
-                "source": "openlibrary"
-            })
+        # Iterate through providers until a book is found
+        for provider in providers:
+            book_data = provider(clean_isbn)
+            
+            if book_data:
+                # Add the ISBN back into the response payload
+                book_data["isbn"] = clean_isbn
+                
+                # If a provider found the book but had no cover, assign a default OpenLibrary cover fallback
+                if not book_data.get("thumbnail"):
+                    book_data["thumbnail"] = f"https://covers.openlibrary.org/b/isbn/{clean_isbn}-L.jpg"
+                    
+                return jsonify(book_data)
 
+        # If all providers fail
         return jsonify({"error": f"Kein Buch zu dieser ISBN gefunden: {clean_isbn}"}), 404
         
     except Exception as e:

Web/templates/base.html

@@ -1295,11 +1295,6 @@
                         </li>
                         {% endif %}
                         {% if 'username' in session %}
-                        {% if current_permissions.pages.get('my_borrowed_items', True) %}
-                        <li class="nav-item">
-                            <a class="nav-link quick-link-pill {% if current_path == url_for('my_borrowed_items') %}nav-active{% endif %}" href="{{ url_for('my_borrowed_items') }}" data-tutorial-tip="Hier sehen Sie Ihre bibliotheksbezogenen Ausleihen.">Meine Medien</a>
-                        </li>
-                        {% endif %}
                         {% if current_permissions.pages.get('tutorial_page', True) %}
                         <li class="nav-item">
                             <a class="nav-link quick-link-pill {% if current_path == url_for('tutorial_page') %}nav-active{% endif %}" href="{{ url_for('tutorial_page') }}" data-tutorial-tip="Nutzen Sie das Tutorial, um die Bibliotheksfunktionen kennenzulernen.">Tutorial</a>

Web/templates/library_table.html

@@ -431,7 +431,7 @@
             type="text" 
             id="librarySearch" 
             class="library-search-input" 
-            placeholder="Nach Titel, Autor, ISBN suchen..."
+            placeholder="Nach Titel, ISBN suchen..."
         >
         <button 
             id="filterToggleBtn" 
@@ -445,7 +445,7 @@
     <!-- Customizable Filter Panel -->
 
     <!-- Student card / quick scan workflow -->
-    <div class="library-scan-panel">
+   <div class="library-scan-panel">
         <div class="library-scan-controls">
             <select id="scanModeSelect" aria-label="Scan-Modus">
                 <option value="card_only">Nur Ausweis erfassen</option>
@@ -458,16 +458,14 @@
         <div id="scanStatus" class="library-scan-status">
             Hinweis: Im Schnellmodus zuerst den Schülerausweis scannen, danach den Buch-/Mediencode.
         </div>
-        <div id="scanReaderWrap" class="library-scan-reader-wrap">
-            <div id="libraryQrReader" class="library-scan-reader"></div>
+        <div id="scanReaderWrap" class="library-scan-reader-wrap" style="display: none;">
+            <div id="libraryQrReader" class="library-scan-reader">
+                <div id="library-scanner-container"></div>
+            </div>
         </div>
     </div>
     <div id="filterPanel" class="library-filter-panel">
         <div class="filter-row">
-            <div class="filter-item">
-                <label for="filterAuthor">Autor/Künstler:</label>
-                <input type="text" id="filterAuthor" placeholder="z.B. Goethe">
-            </div>
             <div class="filter-item">
                 <label for="filterISBN">ISBN:</label>
                 <input type="text" id="filterISBN" placeholder="z.B. 978-3...">
@@ -514,7 +512,6 @@
             <thead>
                 <tr>
                     <th style="width: 24%;">Titel</th>
-                    <th style="width: 14%;">Autor/Künstler</th>
                     <th style="width: 12%;">ISBN/Code</th>
                     <th style="width: 8%;">Typ</th>
                     <th style="width: 8%;">Anzahl</th>
@@ -547,15 +544,17 @@
     </div>
 </div>
 
+<script src="https://cdn.jsdelivr.net/npm/@ericblade/quagga2/dist/quagga.js"></script>
 <script src="https://cdn.jsdelivr.net/npm/@ericblade/quagga2/dist/quagga.js"></script>
 <script>
-    // State
+    // =========================================================================
+    // 1. GLOBAL STATE DEFINITIONS
+    // =========================================================================
     let libraryItems = [];
     let filteredItems = [];
     let visibleItems = [];
     let currentSearchTerm = '';
     let activeFilters = {
-        author: '',
         isbn: '',
         type: '',
         status: ''
@@ -571,13 +570,20 @@
     const RENDER_BATCH_COUNT = 120;
     let renderedCount = INITIAL_RENDER_COUNT;
     let filterPanelOpen = false;
+    
+    // Scanner Related State Variables
     let scannerInstance = null;
-    let scannerRunning = false;
+    let scannerRunning = false; 
+    let activeScannerCallback = null; 
     let activeStudentCardId = '';
     let lastScanValue = '';
     let lastScanAt = 0;
+    
     const canEditLibraryItems = (document.getElementById('libraryTableContainer')?.dataset.canEdit === '1');
 
+    // =========================================================================
+    // 2. DATA LOADING & FILTERING ENGINE
+    // =========================================================================
     async function fetchLibraryPage(offset, limit) {
         const response = await fetch(`/api/library_items?offset=${offset}&limit=${limit}`);
         if (!response.ok) {
@@ -586,7 +592,6 @@
         return response.json();
     }
 
-    // Load items progressively: first page immediately, rest in background
     async function loadLibraryItems() {
         if (pagingState.loading) return;
         pagingState.loading = true;
@@ -625,7 +630,6 @@
                 pagingState.total = page.total || pagingState.total;
                 pagingState.hasMore = Boolean(page.has_more);
 
-                // Keep the current view reactive while avoiding a full rerender burst.
                 applyFiltersAndSearch(false);
 
                 if ('requestIdleCallback' in window) {
@@ -641,18 +645,16 @@
     }
 
     function filterItems(items) {
-        const author = activeFilters.author;
         const isbn = activeFilters.isbn;
         const type = activeFilters.type;
         const status = activeFilters.status;
 
         return items.filter(item => {
-            const authorMatch = !author || (item.Autor || item.Author || '').toLowerCase().includes(author);
             const isbnMatch = !isbn || (item.ISBN || item.Code_4 || item.Code4 || '').toLowerCase().includes(isbn);
             const typeMatch = !type || (item.ItemType || 'book') === type;
             const statusKey = item.LibraryDisplayStatus || (item.Verfuegbar === false ? 'borrowed' : 'available');
             const statusMatch = !status || statusKey === status;
-            return authorMatch && isbnMatch && typeMatch && statusMatch;
+            return isbnMatch && typeMatch && statusMatch;
         });
     }
 
@@ -660,7 +662,6 @@
         if (!currentSearchTerm) return items;
         return items.filter(item =>
             (item.Name || '').toLowerCase().includes(currentSearchTerm) ||
-            (item.Autor || item.Author || '').toLowerCase().includes(currentSearchTerm) ||
             (item.ISBN || item.Code_4 || item.Code4 || '').toLowerCase().includes(currentSearchTerm)
         );
     }
@@ -677,7 +678,6 @@
         renderItems();
     }
 
-    // Display current view with incremental rendering
     function renderItems() {
         const tbody = document.getElementById('itemsTableBody');
         const emptyState = document.getElementById('emptyState');
@@ -695,37 +695,33 @@
         emptyState.style.display = 'none';
         const rowsToRender = visibleItems.slice(0, renderedCount);
 
-        tbody.innerHTML = rowsToRender.map(item => `
-            ${(() => {
-                const statusKey = item.LibraryDisplayStatus || (item.Verfuegbar === false ? 'borrowed' : 'available');
-                const statusClass = statusKey === 'damaged' ? 'status-damaged' : (statusKey === 'borrowed' ? 'status-borrowed' : 'status-available');
-                const statusText = statusKey === 'damaged' ? 'Defekt/Zerstört' : (statusKey === 'borrowed' ? 'Ausgeliehen' : 'Verfügbar');
-                const actionLabel = statusKey === 'available' ? 'Ausleihen' : (statusKey === 'borrowed' ? 'Reservieren' : 'Nicht ausleihbar');
-                const actionDisabled = statusKey === 'damaged' ? 'disabled' : '';
-                return `
-            <tr>
-                <td class="table-title">${escapeHtml(item.Name || 'Untitled')}</td>
-                <td>${escapeHtml(item.Autor || item.Author || '-')}</td>
-                <td>${escapeHtml(item.ISBN || item.Code_4 || item.Code4 || '-')}</td>
-                <td>${getItemTypeLabel(item.ItemType || 'book')}</td>
-                <td style="font-weight:600; text-align:center;">${item.Quantity || item.GroupedDisplayCount || 1}</td>
-                <td>
-                    <span class="table-status ${statusClass}">
-                        ${statusText}
-                    </span>
-                </td>
-                <td class="table-actions">
-                    <button class="button" onclick="showItemDetail('${item._id}')">Details</button>
-                    <button class="button" style="background: #28a745; color: white;" onclick="borrowItem('${item._id}')" ${actionDisabled}>
-                        ${actionLabel}
-                    </button>
-                    ${canEditLibraryItems ? `<button class="button" style="background:#0ea5e9;color:#fff;" onclick="openEditLibraryItem('${item._id}')">Bearbeiten</button>` : ''}
-                    ${canEditLibraryItems ? `<button class="button" style="background:#dc2626;color:#fff; margin-left:6px;" onclick="confirmDeleteLibraryItem('${item._id}')">Löschen</button>` : ''}
-                </td>
-            </tr>
-                `;
-            })()}
-        `).join('');
+        tbody.innerHTML = rowsToRender.map(item => {
+            const statusKey = item.LibraryDisplayStatus || (item.Verfuegbar === false ? 'borrowed' : 'available');
+            const statusClass = statusKey === 'damaged' ? 'status-damaged' : (statusKey === 'borrowed' ? 'status-borrowed' : 'status-available');
+            const statusText = statusKey === 'damaged' ? 'Defekt/Zerstört' : (statusKey === 'borrowed' ? 'Ausgeliehen' : 'Verfügbar');
+            const actionLabel = statusKey === 'available' ? 'Ausleihen' : (statusKey === 'borrowed' ? 'Reservieren' : 'Nicht ausleihbar');
+            const actionDisabled = statusKey === 'damaged' ? 'disabled' : '';
+            return `
+        <tr>
+            <td class="table-title">${escapeHtml(item.Name || 'Untitled')}</td>
+            <td>${escapeHtml(item.ISBN || item.Code_4 || item.Code4 || '-')}</td>
+            <td>${getItemTypeLabel(item.ItemType || 'book')}</td>
+            <td style="font-weight:600; text-align:center;">${item.Quantity || item.GroupedDisplayCount || 1}</td>
+            <td>
+                <span class="table-status ${statusClass}">
+                    ${statusText}
+                </span>
+            </td>
+            <td class="table-actions">
+                <button class="button" onclick="showItemDetail('${item._id}')">Details</button>
+                <button class="button" style="background: #28a745; color: white;" onclick="borrowItem('${item._id}')" ${actionDisabled}>
+                    ${actionLabel}
+                </button>
+                ${canEditLibraryItems ? `<button class="button" style="background:#0ea5e9;color:#fff;" onclick="openEditLibraryItem('${item._id}')">Bearbeiten</button>` : ''}
+                ${canEditLibraryItems ? `<button class="button" style="background:#dc2626;color:#fff; margin-left:6px;" onclick="confirmDeleteLibraryItem('${item._id}')">Löschen</button>` : ''}
+            </td>
+        </tr>`;
+        }).join('');
 
         const canLoadMoreRows = renderedCount < visibleItems.length;
         if (canLoadMoreRows) {
@@ -740,13 +736,6 @@
         }
     }
 
-    // Confirm and call library item delete endpoint
-    function confirmDeleteLibraryItem(itemId) {
-        if (!itemId) return;
-        if (!confirm('Dieses Bibliotheksmedium revisionssicher löschen? Diese Aktion deaktiviert alle zugehörigen Exemplare und archiviert Medien.')) return;
-        deleteLibraryItem(itemId);
-    }
-
     async function deleteLibraryItem(itemId) {
         if (!itemId) return;
         document.body.style.cursor = 'wait';
@@ -770,7 +759,6 @@
                 }
                 loadLibraryItems();
             } else {
-                // Server redirected to HTML (flash messages). Reload to show state.
                 location.reload();
             }
         } catch (e) {
@@ -781,46 +769,269 @@
         }
     }
 
-    // Filter toggle
-    document.getElementById('filterToggleBtn').addEventListener('click', () => {
-        filterPanelOpen = !filterPanelOpen;
-        const panel = document.getElementById('filterPanel');
-        const btn = document.getElementById('filterToggleBtn');
-        panel.classList.toggle('open');
-        btn.classList.toggle('active');
+    function confirmDeleteLibraryItem(itemId) {
+        if (!itemId) return;
+        if (!confirm('Dieses Bibliotheksmedium revisionssicher löschen? Diese Aktion deaktiviert alle zugehörigen Exemplare und archiviert Medien.')) return;
+        deleteLibraryItem(itemId);
+    }
+
+    // =========================================================================
+    // 3. CORE SCANNER ROUTING ENGINE (QUAGGA2)
+    // =========================================================================
+    function startScanner(targetCallback) {
+        const readerWrap = document.getElementById('scanReaderWrap');
+        const toggleBtn = document.getElementById('toggleScannerBtn');
+        
+        activeScannerCallback = targetCallback;
+
+        if (readerWrap) readerWrap.style.display = 'block';
+        setScanStatus('Initializing camera...', 'warn');
+    
+        Quagga.init({
+            inputStream: {
+                name: "Live",
+                type: "LiveStream",
+                target: document.querySelector('#library-scanner-container'), 
+                constraints: {
+                    width: 640,
+                    height: 480,
+                    facingMode: "environment" 
+                },
+            },
+            decoder: {
+                readers: [
+                    "code_128_reader", 
+                    "ean_reader", 
+                    "code_39_reader", 
+                    "upc_reader", 
+                    "codabar_reader", 
+                    "i2of5_reader"
+                ]
+            } 
+        }, function(err) {
+            if (err) {
+                console.error('Scanner start failed:', err);
+                if (readerWrap) readerWrap.style.display = 'none';
+                const detail = (err && (err.message || err.name)) ? ` (${err.message || err.name})` : '';
+                setScanStatus(`Scanner konnte nicht gestartet werden${detail}`, 'error');
+                return;
+            }
+        
+            Quagga.start();
+            scannerRunning = true;
+            
+            if (!targetCallback && toggleBtn) {
+                toggleBtn.textContent = 'Scanner stoppen';
+            }
+            setScanStatus('Scanner aktiv. Jetzt Code scannen.', 'warn');
+        });
+    }
+    
+    function stopScanner() {
+        if (!scannerRunning) return;
+        
+        const readerWrap = document.getElementById('scanReaderWrap');
+        const toggleBtn = document.getElementById('toggleScannerBtn');
+    
+        Quagga.stop();
+        scannerRunning = false;
+        activeScannerCallback = null; 
+    
+        if (readerWrap) readerWrap.style.display = 'none';
+        if (toggleBtn) toggleBtn.textContent = 'Scanner starten';
+        setScanStatus('Scanner gestoppt.', 'warn');
+    }
+    
+    Quagga.onDetected(function(data) {
+        if (!data || !data.codeResult || !data.codeResult.code) return;
+        
+        const barcode = String(data.codeResult.code || '').trim();
+        console.log("Barcode detected:", barcode);
+    
+        const currentCallback = activeScannerCallback;
+        stopScanner();
+    
+        if (typeof currentCallback === "function") {
+            currentCallback(barcode);
+        } else {
+            handleScanSuccess(barcode);
+        }
     });
 
-    // Apply filters
-    document.getElementById('applyFilterBtn').addEventListener('click', () => {
-        activeFilters.author = document.getElementById('filterAuthor').value.toLowerCase();
-        activeFilters.isbn = document.getElementById('filterISBN').value.toLowerCase();
-        activeFilters.type = document.getElementById('filterType').value;
-        activeFilters.status = document.getElementById('filterStatus').value;
-        applyFiltersAndSearch(true);
-    });
+    function handleScanSuccess(decodedText) {
+        const scannedCode = normalizeScannedCode(decodedText);
+        if (!scannedCode) return;
+    
+        const now = Date.now();
+        if (scannedCode === lastScanValue && (now - lastScanAt) < 1500) {
+            return;
+        }
+        lastScanValue = scannedCode;
+        lastScanAt = now;
+    
+        const mode = (document.getElementById('scanModeSelect') || {}).value || 'card_only';
+        if (mode === 'card_only') {
+            setActiveStudentCard(scannedCode);
+            setScanStatus(`Ausweis gesetzt: ${activeStudentCardId}`, 'ok');
+            return;
+        }
+    
+        processQuickToggleScan(scannedCode);
+    }
 
-    // Clear filters
-    document.getElementById('clearFilterBtn').addEventListener('click', () => {
-        document.getElementById('filterAuthor').value = '';
-        document.getElementById('filterISBN').value = '';
-        document.getElementById('filterType').value = '';
-        document.getElementById('filterStatus').value = '';
-        activeFilters = { author: '', isbn: '', type: '', status: '' };
-        applyFiltersAndSearch(true);
-    });
+    async function processQuickToggleScan(scannedCode) {
+        if (!activeStudentCardId) {
+            setActiveStudentCard(scannedCode);
+            setScanStatus(`Ausweis gesetzt: ${activeStudentCardId}`, 'ok');
+            return;
+        }
+    
+        try {
+            setScanStatus('Verarbeite Mediencode...', 'warn');
+            const response = await fetch('/api/library_scan_action', {
+                method: 'POST',
+                headers: {'Content-Type': 'application/json'},
+                body: JSON.stringify({
+                    student_card_id: activeStudentCardId,
+                    item_code: scannedCode
+                })
+            });
+        
+            const result = await response.json();
+            if (!response.ok || !result.ok) {
+                setScanStatus(result.message || 'Scan-Aktion fehlgeschlagen.', 'error');
+                return;
+            }
+        
+            if (result.action === 'borrowed') {
+                setScanStatus(`Ausgeliehen: ${result.item_name}`, 'ok');
+            } else if (result.action === 'returned') {
+                setScanStatus(`Zurückgegeben: ${result.item_name}`, 'ok');
+            } else {
+                setScanStatus(result.message || 'Aktion durchgeführt.', 'ok');
+            }
+        
+            await loadLibraryItems();
+        } catch (err) {
+            console.error('Quick scan action failed:', err);
+            setScanStatus('Fehler beim Verarbeiten des Scans.', 'error');
+        }
+    }
 
-    // Search input
-    document.getElementById('librarySearch').addEventListener('input', (e) => {
-        currentSearchTerm = (e.target.value || '').toLowerCase();
-        applyFiltersAndSearch(true);
-    });
+    function scanIntoEditCode() {
+        const scanReaderWrap = document.getElementById('scanReaderWrap');
+        const editCodeInput = document.getElementById('edit-code4');
+        const scanEditBtn = document.getElementById('scan-edit-code-btn');
+        if (!scanReaderWrap || !editCodeInput || !scanEditBtn) {
+            return;
+        }
+    
+        if (scannerRunning && scanReaderWrap.style.display !== 'none') {
+            stopScanner();
+            scanEditBtn.textContent = 'Barcode scannen';
+            return;
+        }
+    
+        scanEditBtn.textContent = 'Scanner schließen';
+    
+        startScanner(function(decodedText) {
+            editCodeInput.value = decodedText;
+            if(typeof validateCodeField === "function") {
+                validateCodeField(editCodeInput, document.getElementById('edit-item-id')?.value || null);
+            }
+            scanEditBtn.textContent = 'Barcode scannen';
+        });
+    }
 
-    document.getElementById('loadMoreBtn').addEventListener('click', () => {
-        renderedCount = Math.min(renderedCount + RENDER_BATCH_COUNT, visibleItems.length);
-        renderItems();
-    });
+    // =========================================================================
+    // 4. UI INTERACTIONS & UTILITIES
+    // =========================================================================
+    function borrowItem(itemId) {
+        const selectedItem = (libraryItems || []).find(item => item._id === itemId);
+        if (selectedItem && selectedItem.LibraryDisplayStatus === 'damaged') {
+            alert('Dieses Medium ist als defekt/zerstört markiert und kann nicht ausgeliehen werden.');
+            return;
+        }
+    
+        const defaultCardId = activeStudentCardId || '';
+        const cardId = (window.prompt('Bitte Schülerausweis-ID eingeben:', defaultCardId) || '').trim().toUpperCase();
+        if (!cardId) {
+            alert('Ausleihe abgebrochen: Für Bibliotheksmedien ist eine gültige Schülerausweis-ID erforderlich.');
+            return;
+        }
+    
+        setActiveStudentCard(cardId);
+    
+        const durationInput = (window.prompt('Ausleihdauer in Tagen (optional):') || '').trim();
+        const maxAvailable = Math.max(1, parseInt(selectedItem?.AvailableGroupedCount || selectedItem?.Quantity || 1, 10) || 1);
+        const countPrompt = (window.prompt(`Anzahl ausleihen? (Standard: 1, verfügbar: ${maxAvailable})`, '1') || '').trim();
+        let borrowCount = parseInt(countPrompt || '1', 10);
+        if (!Number.isFinite(borrowCount) || borrowCount < 1) {
+            borrowCount = 1;
+        }
+        if (borrowCount > maxAvailable) {
+            alert(`Es sind nur ${maxAvailable} Exemplar(e) verfügbar.`);
+            return;
+        }
+    
+        const form = document.createElement('form');
+        form.method = 'POST';
+        form.action = `/ausleihen/${itemId}`;
+    
+        const csrfField = document.createElement('input');
+        csrfField.type = 'hidden';
+        csrfField.name = 'csrf_token';
+        csrfField.value = '{{ csrf_token }}';
+        form.appendChild(csrfField);
+    
+        const cardField = document.createElement('input');
+        cardField.type = 'hidden';
+        cardField.name = 'borrower_card_id';
+        cardField.value = cardId;
+        form.appendChild(cardField);
+    
+        const returnTargetField = document.createElement('input');
+        returnTargetField.type = 'hidden';
+        returnTargetField.name = 'return_to';
+        returnTargetField.value = 'library';
+        form.appendChild(returnTargetField);
+    
+        if (durationInput) {
+            const durationField = document.createElement('input');
+            durationField.type = 'hidden';
+            durationField.name = 'borrow_duration_days';
+            durationField.value = durationInput;
+            form.appendChild(durationField);
+        }
+    
+        const countField = document.createElement('input');
+        countField.type = 'hidden';
+        countField.name = 'exemplare_count';
+        countField.value = String(borrowCount || 1);
+        form.appendChild(countField);
+    
+        document.body.appendChild(form);
+        form.submit();
+    }
+
+    function setScanStatus(message, kind = '') {
+        const el = document.getElementById('scanStatus');
+        if (!el) return;
+        el.textContent = message;
+        el.classList.remove('ok', 'warn', 'error');
+        if (kind) el.classList.add(kind);
+    }
+    
+    function setActiveStudentCard(cardId) {
+        activeStudentCardId = (cardId || '').trim().toUpperCase();
+        const input = document.getElementById('activeStudentCard');
+        if (input) input.value = activeStudentCardId;
+    }
+    
+    function normalizeScannedCode(code) {
+        return (code || '').trim();
+    }
 
-    // Helper functions
     function getItemTypeLabel(type) {
         const labels = { 'book': 'Buch', 'cd': 'CD', 'dvd': 'DVD', 'other': 'Sonstige' };
         return labels[type] || type;
@@ -833,7 +1044,6 @@
     }
 
     function showItemDetail(itemId) {
-        // Load and show detail modal
         fetch(`/api/item_detail/${itemId}`)
             .then(r => r.text())
             .then(html => {
@@ -847,335 +1057,165 @@
         document.getElementById('detailModal').style.display = 'none';
     }
 
-        // Keep track of the scanner state globally/outer scope
-    let scannerRunning = false;
-    let lastScanValue = null;
-    let lastScanAt = 0;
-    let activeStudentCardId = ''; // Managed globally by your system
-
-    function borrowItem(itemId) {
-        const selectedItem = (libraryItems || []).find(item => item._id === itemId);
-        if (selectedItem && selectedItem.LibraryDisplayStatus === 'damaged') {
-            alert('Dieses Medium ist als defekt/zerstör markiert und kann nicht ausgeliehen werden.');
-            return;
-        }
-
-        const defaultCardId = activeStudentCardId || '';
-        const cardId = (window.prompt('Bitte Schülerausweis-ID eingeben:', defaultCardId) || '').trim().toUpperCase();
-        if (!cardId) {
-            alert('Ausleihe abgebrochen: Für Bibliotheksmedien ist eine gültige Schülerausweis-ID erforderlich.');
-            return;
-        }
-
-        setActiveStudentCard(cardId);
-
-        const durationInput = (window.prompt('Ausleihdauer in Tagen (optional):') || '').trim();
-        const maxAvailable = Math.max(1, parseInt(selectedItem?.AvailableGroupedCount || selectedItem?.Quantity || 1, 10) || 1);
-        const countPrompt = (window.prompt(`Anzahl ausleihen? (Standard: 1, verfügbar: ${maxAvailable})`, '1') || '').trim();
-        let borrowCount = parseInt(countPrompt || '1', 10);
-        if (!Number.isFinite(borrowCount) || borrowCount < 1) {
-            borrowCount = 1;
-        }
-        if (borrowCount > maxAvailable) {
-            alert(`Es sind nur ${maxAvailable} Exemplar(e) verfügbar.`);
-            return;
-        }
-
-        const form = document.createElement('form');
-        form.method = 'POST';
-        form.action = `/ausleihen/${itemId}`;
-
-        const csrfField = document.createElement('input');
-        csrfField.type = 'hidden';
-        csrfField.name = 'csrf_token';
-        csrfField.value = '{{ csrf_token }}';
-        form.appendChild(csrfField);
-
-        const cardField = document.createElement('input');
-        cardField.type = 'hidden';
-        cardField.name = 'borrower_card_id';
-        cardField.value = cardId;
-        form.appendChild(cardField);
-
-        const returnTargetField = document.createElement('input');
-        returnTargetField.type = 'hidden';
-        returnTargetField.name = 'return_to';
-        returnTargetField.value = 'library';
-        form.appendChild(returnTargetField);
-
-        if (durationInput) {
-            const durationField = document.createElement('input');
-            durationField.type = 'hidden';
-            durationField.name = 'borrow_duration_days';
-            durationField.value = durationInput;
-            form.appendChild(durationField);
-        }
-
-        const countField = document.createElement('input');
-        countField.type = 'hidden';
-        countField.name = 'exemplare_count';
-        countField.value = String(borrowCount || 1);
-        form.appendChild(countField);
-
-        document.body.appendChild(form);
-        form.submit();
-    }
-
-    function setScanStatus(message, kind = '') {
-        const el = document.getElementById('scanStatus');
-        if (!el) return;
-        el.textContent = message;
-        el.classList.remove('ok', 'warn', 'error');
-        if (kind) {
-            el.classList.add(kind);
-        }
-    }
-
-    function setActiveStudentCard(cardId) {
-        activeStudentCardId = (cardId || '').trim().toUpperCase();
-        const input = document.getElementById('activeStudentCard');
-        if (input) {
-            input.value = activeStudentCardId;
-        }
-    }
-
-    function normalizeScannedCode(code) {
-        return (code || '').trim();
-    }
-
-    async function processQuickToggleScan(scannedCode) {
-        if (!activeStudentCardId) {
-            setActiveStudentCard(scannedCode);
-            setScanStatus(`Ausweis gesetzt: ${activeStudentCardId}`, 'ok');
-            return;
-        }
-
-        try {
-            setScanStatus('Verarbeite Mediencode...', 'warn');
-            const response = await fetch('/api/library_scan_action', {
-                method: 'POST',
-                headers: {'Content-Type': 'application/json'},
-                body: JSON.stringify({
-                    student_card_id: activeStudentCardId,
-                    item_code: scannedCode
-                })
-            });
-
-            const result = await response.json();
-            if (!response.ok || !result.ok) {
-                setScanStatus(result.message || 'Scan-Aktion fehlgeschlagen.', 'error');
-                return;
-            }
-
-            if (result.action === 'borrowed') {
-                setScanStatus(`Ausgeliehen: ${result.item_name}`, 'ok');
-            } else if (result.action === 'returned') {
-                setScanStatus(`Zurückgegeben: ${result.item_name}`, 'ok');
-            } else {
-                setScanStatus(result.message || 'Aktion durchgeführt.', 'ok');
-            }
-
-            await loadLibraryItems();
-        } catch (err) {
-            console.error('Quick scan action failed:', err);
-            setScanStatus('Fehler beim Verarbeiten des Scans.', 'error');
-        }
-    }
-
-    function handleScanSuccess(decodedText) {
-        const scannedCode = normalizeScannedCode(decodedText);
-        if (!scannedCode) return;
-
-        const now = Date.now();
-        if (scannedCode === lastScanValue && (now - lastScanAt) < 1500) {
-            return;
-        }
-        lastScanValue = scannedCode;
-        lastScanAt = now;
-
-        const mode = (document.getElementById('scanModeSelect') || {}).value || 'card_only';
-        if (mode === 'card_only') {
-            setActiveStudentCard(scannedCode);
-            setScanStatus(`Ausweis gesetzt: ${activeStudentCardId}`, 'ok');
-            return;
-        }
-
-        processQuickToggleScan(scannedCode);
-    }
-
-    // Global Quagga reader hook
-    Quagga.onDetected(function(data) {
-        if (data && data.codeResult && data.codeResult.code) {
-            handleScanSuccess(data.codeResult.code);
-        }
-    });
-
-    async function startScanner() {
-        if (scannerRunning) return;
-
-        const readerWrap = document.getElementById('scanReaderWrap');
-        const toggleBtn = document.getElementById('toggleScannerBtn');
-        if (readerWrap) readerWrap.style.display = 'block';
-
-        setScanStatus('Initializing camera...', 'warn');
-
-        Quagga.init({
-            inputStream: {
-                name: "Live",
-                type: "LiveStream",
-                // Points to the interior viewport layout box
-                target: document.querySelector('#libraryQrReader'), 
-                constraints: {
-                    width: 640,
-                    height: 480,
-                    facingMode: "environment" // Force rear mobile lenses
-                },
-            },
-            decoder: {
-                // Limited down precisely to standard library/ID configurations
-                readers: [
-                    "code_128_reader", 
-                    "ean_reader", 
-                    "code_39_reader", 
-                    "upc_reader", 
-                    "codabar_reader", 
-                    "i2of5_reader" // Matches original 'ITF' format mapping
-                ]
-            } 
-        }, function(err) {
-            if (err) {
-                console.error('Scanner start failed:', err);
-                if (readerWrap) readerWrap.style.display = 'none';
-                const detail = (err && (err.message || err.name)) ? ` (${err.message || err.name})` : '';
-                setScanStatus(`Scanner konnte nicht gestartet werden${detail}`, 'error');
-                return;
-            }
-
-            Quagga.start();
-            scannerRunning = true;
-            if (toggleBtn) toggleBtn.textContent = 'Scanner stoppen';
-            setScanStatus('Scanner aktiv. Jetzt Code scannen.', 'warn');
-        });
-    }
-
-    async function stopScanner() {
-        if (!scannerRunning) return;
-        const readerWrap = document.getElementById('scanReaderWrap');
-        const toggleBtn = document.getElementById('toggleScannerBtn');
-
-        Quagga.stop();
-
-        scannerRunning = false;
-        if (readerWrap) readerWrap.style.display = 'none';
-        if (toggleBtn) toggleBtn.textContent = 'Scanner starten';
-        setScanStatus('Scanner gestoppt.', 'warn');
-    }
-
+// =========================================================================
+    // 5. EVENT LISTENERS INITIALIZATION & ON-LOAD INITIALIZER
+    // =========================================================================
     function wireScannerUi() {
         const toggleBtn = document.getElementById('toggleScannerBtn');
         const resetBtn = document.getElementById('resetCardBtn');
         const modeSelect = document.getElementById('scanModeSelect');
-
+    
         if (toggleBtn) {
             toggleBtn.addEventListener('click', async () => {
                 if (scannerRunning) {
                     await stopScanner();
                 } else {
-                    await startScanner();
+                    await startScanner(null);
                 }
             });
         }
-
+    
         if (resetBtn) {
             resetBtn.addEventListener('click', () => {
                 setActiveStudentCard('');
                 setScanStatus('Ausweis zurückgesetzt. Bitte neu scannen.', 'warn');
             });
         }
-
+    
         if (modeSelect) {
             modeSelect.addEventListener('change', () => {
                 if (modeSelect.value === 'quick_toggle' && !activeStudentCardId) {
                     setScanStatus('Schnellmodus: zuerst Schülerausweis scannen.', 'warn');
                 } else if (modeSelect.value === 'card_only') {
-                    setScanStatus('Modus aktiv: Nur Ausweis erfassen.', 'warn');
-                } else {
-                    setScanStatus('Schnellmodus aktiv: jetzt Mediencode scannen.', 'warn');
+                    setScanStatus('Nur Ausweis-Modus aktiv.', 'warn');
                 }
             });
         }
     }
 
-    function getLibraryItemById(itemId) {
-        return libraryItems.find(i => String(i._id) === String(itemId));
-    }
+    // Run when DOM structure is entirely ready
+    document.addEventListener('DOMContentLoaded', () => {
+        wireScannerUi();       // Setup scanner control buttons 
+        loadLibraryItems();   // Fetch your database items right away!
 
+        // Safely connect standard Filters and Search inputs inside DOMContentLoaded
+        const filterToggleBtn = document.getElementById('filterToggleBtn');
+        if (filterToggleBtn) {
+            filterToggleBtn.addEventListener('click', () => {
+                filterPanelOpen = !filterPanelOpen;
+                document.getElementById('filterPanel').classList.toggle('open');
+                filterToggleBtn.classList.toggle('active');
+            });
+        }
+
+        const applyFilterBtn = document.getElementById('applyFilterBtn');
+        if (applyFilterBtn) {
+            applyFilterBtn.addEventListener('click', () => {
+                activeFilters.isbn = document.getElementById('filterISBN').value.toLowerCase();
+                activeFilters.type = document.getElementById('filterType').value;
+                activeFilters.status = document.getElementById('filterStatus').value;
+                applyFiltersAndSearch(true);
+            });
+        }
+
+        const clearFilterBtn = document.getElementById('clearFilterBtn');
+        if (clearFilterBtn) {
+            clearFilterBtn.addEventListener('click', () => {
+                document.getElementById('filterISBN').value = '';
+                document.getElementById('filterType').value = '';
+                document.getElementById('filterStatus').value = '';
+                activeFilters = { isbn: '', type: '', status: '' };
+                applyFiltersAndSearch(true);
+            });
+        }
+
+        const librarySearch = document.getElementById('librarySearch');
+        if (librarySearch) {
+            librarySearch.addEventListener('input', (e) => {
+                currentSearchTerm = (e.target.value || '').toLowerCase();
+                applyFiltersAndSearch(true);
+            });
+        }
+
+        const loadMoreBtn = document.getElementById('loadMoreBtn');
+        if (loadMoreBtn) {
+            loadMoreBtn.addEventListener('click', () => {
+                renderedCount = Math.min(renderedCount + RENDER_BATCH_COUNT, visibleItems.length);
+                renderItems();
+            });
+        }
+
+        // Edit Modal Form processing
+        const editForm = document.getElementById('editLibraryForm');
+        if (editForm) {
+            editForm.addEventListener('submit', async function(e) {
+                e.preventDefault(); 
+
+                const itemId = document.getElementById('editLibraryItemId').value;
+
+                const updatedData = {
+                    name: document.getElementById('editLibraryName').value,
+                    item_type: document.getElementById('editLibraryType').value,
+                    isbn: document.getElementById('editLibraryIsbn').value,
+                    code_4: document.getElementById('editLibraryCode4').value, 
+                    ort: document.getElementById('editLibraryLocation').value,
+                    beschreibung: document.getElementById('editLibraryDescription').value
+                };
+
+                try {
+                    const response = await fetch(`/api/library_item/${itemId}/update`, {
+                        method: 'POST',
+                        headers: {
+                            'Content-Type': 'application/json',
+                            'X-CSRFToken': '{{ csrf_token }}', 
+                            'X-CSRF-Token': '{{ csrf_token }}'
+                        },
+                        body: JSON.stringify(updatedData)
+                    });
+
+                    const result = await response.json();
+
+                    if (response.ok && result.ok) {
+                        alert(result.message || 'Medium erfolgreich aktualisiert!');
+                        closeEditLibraryModal();
+
+                        pagingState.loading = false; 
+                        loadLibraryItems(); 
+                    } else {
+                        alert(result.message || 'Fehler beim Speichern der Änderungen.');
+                    }
+                } catch (error) {
+                    console.error('Update failed:', error);
+                    alert('Netzwerkfehler beim Aktualisieren des Mediums.');
+                }
+            });
+        }
+    });
+
+    // Modal Control Functions (accessible globally from table buttons)
     function openEditLibraryItem(itemId) {
-        const item = getLibraryItemById(itemId);
+        const item = libraryItems.find(i => i._id === itemId);
+        
         if (!item) {
-            alert('Element nicht gefunden.');
+            alert('Fehler: Das Medium konnte nicht gefunden werden.');
             return;
         }
 
-        const modal = document.getElementById('editLibraryModal');
+        // Populate the form fields - Using correct German properties from MongoDB fields
         document.getElementById('editLibraryItemId').value = item._id || '';
         document.getElementById('editLibraryName').value = item.Name || '';
-        document.getElementById('editLibraryAuthor').value = item.Autor || item.Author || '';
-        document.getElementById('editLibraryDescription').value = item.Beschreibung || '';
-        document.getElementById('editLibraryLocation').value = item.Ort || '';
+        document.getElementById('editLibraryType').value = item.ItemType || 'book';
         document.getElementById('editLibraryIsbn').value = item.ISBN || '';
-        document.getElementById('editLibraryCode4').value = item.Code_4 || '';
-        document.getElementById('editLibraryType').value = (item.ItemType || 'book');
-        modal.style.display = 'flex';
+        document.getElementById('editLibraryCode4').value = item.Code_4 || item.Code4 || '';
+        document.getElementById('editLibraryLocation').value = item.Ort || ''; 
+        document.getElementById('editLibraryDescription').value = item.Beschreibung || '';
+
+        document.getElementById('editLibraryModal').style.display = 'block'; 
     }
 
     function closeEditLibraryModal() {
-        const modal = document.getElementById('editLibraryModal');
-        modal.style.display = 'none';
+        document.getElementById('editLibraryModal').style.display = 'none';
     }
-
-    async function submitEditLibraryItem(event) {
-        event.preventDefault();
-        const itemId = document.getElementById('editLibraryItemId').value;
-        const payload = {
-            name: document.getElementById('editLibraryName').value,
-            autor: document.getElementById('editLibraryAuthor').value,
-            beschreibung: document.getElementById('editLibraryDescription').value,
-            ort: document.getElementById('editLibraryLocation').value,
-            isbn: document.getElementById('editLibraryIsbn').value,
-            code_4: document.getElementById('editLibraryCode4').value,
-            item_type: document.getElementById('editLibraryType').value
-        };
-
-        try {
-            const response = await fetch(`/api/library_item/${itemId}/update`, {
-                method: 'POST',
-                headers: {'Content-Type': 'application/json'},
-                body: JSON.stringify(payload)
-            });
-            const result = await response.json();
-            if (!response.ok || !result.ok) {
-                alert(result.message || 'Bearbeiten fehlgeschlagen.');
-                return;
-            }
-            closeEditLibraryModal();
-            await loadLibraryItems();
-            setScanStatus('Bibliotheksmedium aktualisiert.', 'ok');
-        } catch (err) {
-            console.error('Library edit failed:', err);
-            alert('Fehler beim Bearbeiten des Bibliotheksmediums.');
-        }
-    }
-
-    // Load on page init
-    document.addEventListener('DOMContentLoaded', () => {
-        loadLibraryItems();
-        wireScannerUi();
-        const editForm = document.getElementById('editLibraryForm');
-        if (editForm) {
-            editForm.addEventListener('submit', submitEditLibraryItem);
-        }
-    });
 </script>
 
 <div id="editLibraryModal" class="modal" style="display:none;">
@@ -1189,10 +1229,6 @@
                     <label for="editLibraryName">Titel</label>
                     <input id="editLibraryName" required>
                 </div>
-                <div>
-                    <label for="editLibraryAuthor">Autor/Künstler</label>
-                    <input id="editLibraryAuthor">
-                </div>
                 <div>
                     <label for="editLibraryType">Medientyp</label>
                     <select id="editLibraryType">
@@ -1227,4 +1263,4 @@
         </form>
     </div>
 </div>
-{% endblock %}
+{% endblock %}

Web/templates/upload_admin.html

@@ -970,8 +970,7 @@
         document.getElementById('csv-help-modal').style.display = 'none';
     }
 </script>
-
-<script src="https://unpkg.com/html5-qrcode@2.0.9/dist/html5-qrcode.min.js"></script>
+<script src="https://cdn.jsdelivr.net/npm/@ericblade/quagga2/dist/quagga.js"></script>
 <script>
     const libraryModuleEnabled = {{ 'true' if library_module_enabled else 'false' }};
 
@@ -984,12 +983,12 @@
 
     // Global variable to store fetched book data
     let currentBookData = null;
-    let code4ScannerInstance = null;
-    let code4ScannerRunning = false;
+    
+    // Quagga2 engine state management properties
+    let scannerRunning = false;
+    let activeScannerCallback = null; // Dynamically handles routing data to the active caller field
     let code4LastScanned = '';
     let code4LastScannedAt = 0;
-    let isbnScannerInstance = null;
-    let isbnScannerRunning = false;
 
     function setCode4ScanStatus(message, isError = false) {
         const statusEl = document.getElementById('code4-scan-status');
@@ -1042,56 +1041,109 @@
         statusEl.style.color = '#b00020';
     }
 
+    // Centered Quagga2 Engine Initialization Pattern
+    function runEngineInitialization(targetSelector, activeCallback, completionMsg, errorStatusSetter) {
+        if (scannerRunning) {
+            Quagga.stop();
+            scannerRunning = false;
+        }
+
+        activeScannerCallback = activeCallback;
+
+        Quagga.init({
+            inputStream: {
+                name: "Live",
+                type: "LiveStream",
+                target: document.querySelector(targetSelector), 
+                constraints: {
+                    width: 640,
+                    height: 480,
+                    facingMode: "environment" // Force rear camera lenses
+                },
+            },
+            decoder: {
+                readers: ["code_128_reader", "ean_reader", "code_39_reader", "upc_reader"]
+            } 
+        }, function(err) {
+            if (err) {
+                console.error("Initialization error:", err);
+                errorStatusSetter("Kamera konnte nicht gestartet werden.", true);
+                return;
+            }
+
+            Quagga.start();
+            scannerRunning = true;
+            errorStatusSetter(completionMsg, false);
+        });
+    }
+
+    function killScannerHardware() {
+        if (!scannerRunning) return;
+        Quagga.stop();
+        scannerRunning = false;
+        activeScannerCallback = null;
+    }
+
+    // Unified tracking capture listener
+    Quagga.onDetected(function(data) {
+        if (!data || !data.codeResult || !data.codeResult.code) return;
+        
+        const rawBarcode = String(data.codeResult.code || '').trim();
+        const currentTargetCallback = activeScannerCallback;
+
+        if (typeof currentTargetCallback === "function") {
+            currentTargetCallback(rawBarcode);
+        }
+    });
+
     function startCode4Scanner() {
         const scannerBox = document.getElementById('code4-scanner');
         const scanButton = document.getElementById('scan-code4-btn');
         const codeField = document.getElementById('code_4');
         if (!scannerBox || !scanButton || !codeField) return;
 
-        // Stop ISBN scanner if currently running to avoid camera conflicts.
-        if (isbnScannerRunning && isbnScannerInstance) {
-            isbnScannerInstance.clear().catch(() => {});
-            const isbnScannerBox = document.getElementById('isbn-scanner');
-            const isbnScanButton = document.getElementById('scan-isbn-btn');
+        // Automatically clean up running ISBN scanner to prevent track multi-binding
+        const isbnScannerBox = document.getElementById('isbn-scanner');
+        const isbnScanButton = document.getElementById('scan-isbn-btn');
+        if (isbnScannerBox && isbnScannerBox.style.display !== 'none') {
+            killScannerHardware();
             if (isbnScannerBox) isbnScannerBox.style.display = 'none';
             if (isbnScanButton) isbnScanButton.textContent = 'ISBN scannen';
-            isbnScannerRunning = false;
+            setIsbnScanStatus('Scanner gestoppt.');
         }
 
-        if (code4ScannerRunning && code4ScannerInstance) {
-            code4ScannerInstance.clear().catch(() => {});
+        if (scannerBox.style.display !== 'none') {
+            killScannerHardware();
             scannerBox.style.display = 'none';
             scanButton.textContent = 'Barcode scannen';
-            code4ScannerRunning = false;
             setCode4ScanStatus('Scanner gestoppt.');
             return;
         }
 
         scannerBox.style.display = 'block';
         scanButton.textContent = 'Scanner stoppen';
-        code4ScannerInstance = new Html5QrcodeScanner('code4-scanner', { 
-            fps: 10, 
-            qrbox: 250,
-            rememberLastUsedCamera: true
-        });
-        code4ScannerRunning = true;
-        setCode4ScanStatus('Scanner läuft. Der Scan wird im Basis-Codefeld übernommen.');
 
-        code4ScannerInstance.render((decodedText) => {
-            const scannedCode = String(decodedText || '').trim();
-            if (!scannedCode) return;
+        runEngineInitialization(
+            '#code4-scanner', 
+            function(decodedText) {
+                const now = Date.now();
+                if (decodedText === code4LastScanned && (now - code4LastScannedAt) < 1500) {
+                    return;
+                }
+                code4LastScanned = decodedText;
+                code4LastScannedAt = now;
 
-            const now = Date.now();
-            if (scannedCode === code4LastScanned && (now - code4LastScannedAt) < 1500) {
-                return;
-            }
-            code4LastScanned = scannedCode;
-            code4LastScannedAt = now;
+                killScannerHardware();
+                scannerBox.style.display = 'none';
+                scanButton.textContent = 'Barcode scannen';
 
-            codeField.value = scannedCode;
-            validateCodeField(codeField);
-            setCode4ScanStatus(`Code_4 gesetzt: ${scannedCode}`);
-        }, () => {});
+                codeField.value = decodedText;
+                validateCodeField(codeField);
+                setCode4ScanStatus(`Code_4 gesetzt: ${decodedText}`);
+            },
+            'Scanner läuft. Der Scan wird im Basis-Codefeld übernommen.',
+            setCode4ScanStatus
+        );
     }
 
     function startIsbnScanner() {
@@ -1104,59 +1156,49 @@
         const isbnField = document.getElementById('isbn');
         if (!scannerBox || !scanButton || !isbnField) return;
 
-        // Stop Code_4 scanner if currently running to avoid camera conflicts.
-        if (code4ScannerRunning && code4ScannerInstance) {
-            code4ScannerInstance.clear().catch(() => {});
-            const codeScannerBox = document.getElementById('code4-scanner');
-            const codeScanButton = document.getElementById('scan-code4-btn');
+        // Automatically clean up running Base Code_4 scanner to prevent track multi-binding
+        const codeScannerBox = document.getElementById('code4-scanner');
+        const codeScanButton = document.getElementById('scan-code4-btn');
+        if (codeScannerBox && codeScannerBox.style.display !== 'none') {
+            killScannerHardware();
             if (codeScannerBox) codeScannerBox.style.display = 'none';
             if (codeScanButton) codeScanButton.textContent = 'Barcode scannen';
-            code4ScannerRunning = false;
             setCode4ScanStatus('Scanner gestoppt.');
         }
 
-        if (isbnScannerRunning && isbnScannerInstance) {
-            isbnScannerInstance.clear().catch(() => {});
+        if (scannerBox.style.display !== 'none') {
+            killScannerHardware();
             scannerBox.style.display = 'none';
             scanButton.textContent = 'ISBN scannen';
-            isbnScannerRunning = false;
             setIsbnScanStatus('Scanner gestoppt.');
             return;
         }
 
         scannerBox.style.display = 'block';
         scanButton.textContent = 'Scanner stoppen';
-        isbnScannerInstance = new Html5QrcodeScanner('isbn-scanner', {
-            fps: 10,
-            qrbox: 250,
-            rememberLastUsedCamera: true
-        });
-        isbnScannerRunning = true;
-        setIsbnScanStatus('Scanner läuft. Bitte ISBN-Code erfassen.');
 
-        isbnScannerInstance.render((decodedText) => {
-            const scannedCode = String(decodedText || '').trim();
-            if (!scannedCode) return;
+        runEngineInitialization(
+            '#isbn-scanner',
+            function(decodedText) {
+                killScannerHardware();
+                scannerBox.style.display = 'none';
+                scanButton.textContent = 'ISBN scannen';
 
-            const normalizedIsbn = normalizeIsbnClient(scannedCode);
-            isbnField.value = normalizedIsbn || scannedCode;
-            updateIsbnLiveValidation();
-            if (normalizedIsbn) {
-                setIsbnScanStatus(`ISBN gesetzt: ${normalizedIsbn}`);
-            } else {
-                setIsbnScanStatus('Kein gültiges ISBN-Format erkannt, der gescannte Wert bleibt aber im Feld.', true);
-            }
+                const normalizedIsbn = normalizeIsbnClient(decodedText);
+                isbnField.value = normalizedIsbn || decodedText;
+                updateIsbnLiveValidation();
 
-            isbnScannerInstance.clear().catch(() => {});
-            scannerBox.style.display = 'none';
-            scanButton.textContent = 'ISBN scannen';
-            isbnScannerRunning = false;
-
-            if (normalizedIsbn) {
-                // Automatically load book metadata after a valid ISBN scan.
-                fetchBookInfo('upload');
-            }
-        }, () => {});
+                if (normalizedIsbn) {
+                    setIsbnScanStatus(`ISBN gesetzt: ${normalizedIsbn}`);
+                    // Automatically load book metadata after a valid ISBN scan.
+                    fetchBookInfo('upload');
+                } else {
+                    setIsbnScanStatus('Kein gültiges ISBN-Format erkannt, der gescannte Wert bleibt aber im Feld.', true);
+                }
+            },
+            'Scanner läuft. Bitte ISBN-Code erfassen.',
+            setIsbnScanStatus
+        );
     }
 
     // Load predefined filter values for dropdowns
@@ -1558,6 +1600,7 @@
         }, 10000);
     }
 
+    // Exported function for use within parent layout fields
     function validateCodeField(input, excludeId = null) {
         const code = input.value.trim();
         
@@ -1732,188 +1775,11 @@
             if (typeof duplicateData.images === 'string') {
                 try {
                     duplicateData.images = JSON.parse(duplicateData.images);
-                    console.log("Parsed images from string:", duplicateData.images);
                 } catch (e) {
-                    console.warn("Failed to parse images string, using as single item:", duplicateData.images);
-                    duplicateData.images = [duplicateData.images];
+                    console.error("Error parsing duplicate images array:", e);
                 }
             }
-            console.log(`Final duplicateData.images (${Array.isArray(duplicateData.images) ? 'array' : typeof duplicateData.images}):`, duplicateData.images);
-        }
-    }
-    
-    // Then check for sessionStorage data (takes priority)
-    const sessionData = sessionStorage.getItem('duplicateItemData');
-    if (sessionData) {
-        try {
-            duplicateData = JSON.parse(sessionData);
-            sessionStorage.removeItem('duplicateItemData'); // Clean up
-            console.log("Session storage duplicate data:", duplicateData);
-        } catch (e) {
-            console.error('Error parsing session duplicate data:', e);
-        }
-    }
-    
-    // Function to prefill form with duplicate data
-    function prefillFormWithDuplicateData() {
-        if (!duplicateData) return;
-        
-        // Fill basic fields
-        const nameField = document.getElementById('name');
-        if (nameField && duplicateData.name) nameField.value = duplicateData.name;
-        
-        const descField = document.getElementById('beschreibung');
-        if (descField && duplicateData.description) descField.value = duplicateData.description;
-        
-        const yearField = document.getElementById('anschaffungsjahr');
-        if (yearField && duplicateData.year) yearField.value = duplicateData.year;
-        
-        const costField = document.getElementById('anschaffungskosten');
-        if (costField && duplicateData.cost) costField.value = duplicateData.cost;
-        
-        // Fill location dropdown
-        const locationField = document.getElementById('ort');
-        if (locationField && duplicateData.location) {
-            // Wait for locations to load, then set value
-            setTimeout(() => {
-                locationField.value = duplicateData.location;
-            }, 100);
-        }
-        
-        // Fill filter arrays - handle up to 4 values per filter type
-        setTimeout(() => {
-            // Filter 1 (Unterrichtsfach)
-            if (duplicateData.filter1 && Array.isArray(duplicateData.filter1)) {
-                for (let j = 1; j <= Math.min(4, duplicateData.filter1.length); j++) {
-                    const filterField = document.getElementById(`filter1-${j}`);
-                    if (filterField && duplicateData.filter1[j-1]) {
-                        filterField.value = duplicateData.filter1[j-1];
-                    }
-                }
-            }
-            
-            // Filter 2 (Jahrgangsstufe)
-            if (duplicateData.filter2 && Array.isArray(duplicateData.filter2)) {
-                for (let j = 1; j <= Math.min(4, duplicateData.filter2.length); j++) {
-                    const filterField = document.getElementById(`filter2-${j}`);
-                    if (filterField && duplicateData.filter2[j-1]) {
-                        filterField.value = duplicateData.filter2[j-1];
-                    }
-                }
-            }
-            
-            // Filter 3 (Thema) - text inputs
-            if (duplicateData.filter3 && Array.isArray(duplicateData.filter3)) {
-                for (let j = 1; j <= Math.min(4, duplicateData.filter3.length); j++) {
-                    const filterField = document.getElementById(`filter3-${j}`);
-                    if (filterField && duplicateData.filter3[j-1]) {
-                        filterField.value = duplicateData.filter3[j-1];
-                    }
-                }
-            }
-        }, 200); // Wait for filter options to load
-        
-        // Handle images - add hidden inputs for duplicate images
-        if (duplicateData.images && duplicateData.images.length > 0) {
-            console.log("Duplicate images data:", duplicateData.images);
-            const form = document.querySelector('form[action*="upload_item"]');
-            if (form) {
-                // Add hidden field to indicate duplication
-                const isDuplicatingField = document.createElement('input');
-                isDuplicatingField.type = 'hidden';
-                isDuplicatingField.name = 'is_duplicating';
-                isDuplicatingField.value = 'true';
-                form.appendChild(isDuplicatingField);
-                
-                // Add each image as a duplicate image
-                const images = duplicateData.images || [];
-                console.log(`Adding ${images.length} images as hidden fields`);
-                
-                if (Array.isArray(images)) {
-                    images.forEach((imageName, index) => {
-                        if (imageName) {
-                            console.log(`Adding duplicate image ${index}: ${imageName}`);
-                            const imageField = document.createElement('input');
-                            imageField.type = 'hidden';
-                            imageField.name = 'duplicate_images';
-                            imageField.value = imageName;
-                            form.appendChild(imageField);
-                        }
-                    });
-                } else {
-                    console.warn("Images is not an array:", images);
-                    // Try to handle as single item if it's a string
-                    if (typeof images === 'string' && images) {
-                        console.log("Adding single image:", images);
-                        const imageField = document.createElement('input');
-                        imageField.type = 'hidden';
-                        imageField.name = 'duplicate_images';
-                        imageField.value = images;
-                        form.appendChild(imageField);
-                    }
-                }
-                
-                // Show image preview
-                showDuplicateImagePreview(duplicateData.images);
-            }
-        }
-    }
-    
-    // Function to show preview of duplicate images
-    function showDuplicateImagePreview(images) {
-        const previewContainer = document.getElementById('image-preview-container');
-        if (!previewContainer) return;
-        
-        console.log("showDuplicateImagePreview called with:", images);
-        
-        // Make sure images is treated as an array
-        if (!Array.isArray(images)) {
-            if (typeof images === 'string') {
-                // Try to parse if it's a JSON string
-                try {
-                    images = JSON.parse(images);
-                } catch (e) {
-                    // If parsing fails, wrap the single string in an array
-                    images = [images];
-                }
-            } else {
-                console.error("Invalid images data:", images);
-                return;
-            }
-        }
-        
-        previewContainer.innerHTML = '';
-        console.log(`Processing ${images.length} images for preview`);
-        
-        images.forEach((imageName, index) => {
-            console.log(`Processing image ${index}:`, imageName);
-            const preview = document.createElement('div');
-            preview.className = 'image-preview-item';
-            preview.innerHTML = `
-                <img src="/uploads/${imageName}" alt="Duplicate Image ${index + 1}" class="duplicate-image-preview">
-                <div class="image-controls">
-                    <span>Von Original übernommen</span>
-                    <button type="button" onclick="removeDuplicateImage('${imageName}', this)" class="remove-duplicate-image-button">Entfernen</button>
-                </div>
-            `;
-            previewContainer.appendChild(preview);
-        });
-    }
-    
-    // Function to remove a duplicate image
-    function removeDuplicateImage(imageName, button) {
-        // Remove the hidden input
-        const hiddenInputs = document.querySelectorAll('input[name="duplicate_images"]');
-        hiddenInputs.forEach(input => {
-            if (input.value === imageName) {
-                input.remove();
-            }
-        });
-        
-        // Remove the preview
-        const previewItem = button.closest('.image-preview-item');
-        if (previewItem) {
-            previewItem.remove();
+            console.log("Parsed duplicate images successfully.");
         }
     }
 </script>