Add keyboard scanner support with toggle option in library table

Web/templates/library_table.html

@@ -505,6 +505,10 @@
             <input type="text" id="activeStudentCard" placeholder="Aktiver Ausweis (gescannt)" readonly>
             <button id="resetCardBtn" class="button" type="button">Ausweis löschen</button>
             <button id="toggleScannerBtn" class="button" type="button">Scanner starten</button>
+            <label style="display:flex; align-items:center; gap:8px; margin-left:6px;">
+                <input type="checkbox" id="keyboardScannerToggle">
+                <span style="font-size:0.9em;">Physischer Scanner</span>
+            </label>
         </div>
         <div id="scanStatus" class="library-scan-status">
             Hinweis: Im Schnellmodus zuerst den Schülerausweis scannen, danach den Buch-/Mediencode.
@@ -632,6 +636,11 @@
     let activeStudentCardId = '';
     let lastScanValue = '';
     let lastScanAt = 0;
+    // Keyboard-scanner support (physical scanners that act as keyboard wedges)
+    let keyboardScannerEnabled = false;
+    let keyboardScanBuffer = '';
+    let keyboardLastKeyAt = 0;
+    const KEYBOARD_SCAN_INTERCHAR_MS = 100; // max time between keystrokes to consider them one scan
     
     const canEditLibraryItems = (document.getElementById('libraryTableContainer')?.dataset.canEdit === '1');
 
@@ -912,6 +921,43 @@
         }
     });
 
+    // =========================================================================
+    // Keyboard scanner handling (physical scanners that send chars then Enter)
+    // =========================================================================
+    function keyboardScanKeydownHandler(e) {
+        // Only active when explicitly enabled
+        if (!keyboardScannerEnabled) return;
+
+        // Ignore if focus is in an input/textarea/contenteditable to avoid interfering with typing
+        const active = document.activeElement;
+        if (active && (active.tagName === 'INPUT' || active.tagName === 'TEXTAREA' || active.isContentEditable)) return;
+
+        const now = Date.now();
+
+        // If Enter/Return pressed -> finalize buffer
+        if (e.key === 'Enter') {
+            const code = keyboardScanBuffer.trim();
+            keyboardScanBuffer = '';
+            keyboardLastKeyAt = 0;
+            if (!code) return;
+            // Process exactly like a camera scan
+            handleScanSuccess(code);
+            return;
+        }
+
+        // Only accept common printable characters; ignore modifier keys
+        if (e.key.length === 1) {
+            // If time gap too big, start new buffer
+            if (keyboardLastKeyAt && (now - keyboardLastKeyAt) > KEYBOARD_SCAN_INTERCHAR_MS) {
+                keyboardScanBuffer = '';
+            }
+            keyboardScanBuffer += e.key;
+            keyboardLastKeyAt = now;
+            // Prevent default so scanner input doesn't accidentally move focus or trigger shortcuts
+            e.preventDefault();
+        }
+    }
+
     function handleScanSuccess(decodedText) {
         const scannedCode = normalizeScannedCode(decodedText);
         if (!scannedCode) return;
@@ -1145,6 +1191,7 @@
         const toggleBtn = document.getElementById('toggleScannerBtn');
         const resetBtn = document.getElementById('resetCardBtn');
         const modeSelect = document.getElementById('scanModeSelect');
+        const keyboardToggle = document.getElementById('keyboardScannerToggle');
     
         if (toggleBtn) {
             toggleBtn.addEventListener('click', async () => {
@@ -1172,6 +1219,19 @@
                 }
             });
         }
+
+        if (keyboardToggle) {
+            keyboardToggle.addEventListener('change', () => {
+                keyboardScannerEnabled = !!keyboardToggle.checked;
+                if (keyboardScannerEnabled) {
+                    document.addEventListener('keydown', keyboardScanKeydownHandler);
+                    setScanStatus('Physischer Scanner aktiv (Schnellmodus empfohlen).', 'ok');
+                } else {
+                    document.removeEventListener('keydown', keyboardScanKeydownHandler);
+                    setScanStatus('Physischer Scanner deaktiviert.', 'warn');
+                }
+            });
+        }
     }
 
     // Run when DOM structure is entirely ready