Implement ISBN live validation and automatic lookup on input change

Web/templates/upload_admin.html

@@ -812,12 +812,12 @@
             <div id="range_generator_group" class="form-group" style="display:none; background: #f9f9f9; padding: 15px; border-radius: 5px; border: 1px solid #ddd; margin-bottom: 15px;">
                 <label style="font-weight: bold;">Code-Bereich automatisch generieren:</label>
                 <div style="display: flex; gap: 10px; margin-bottom: 10px; align-items: center;">
-                    <input type="text" id="range_prefix" placeholder="Präfix (z.B. IT-)" class="form-control" style="flex: 2;">
+                    <input type="text" id="range_prefix" placeholder="Präfix optional (z.B. IT-)" class="form-control" style="flex: 2;">
                     <input type="number" id="range_start" placeholder="Start (z.B. 1)" class="form-control" style="flex: 1;">
                     <span style="font-weight: bold;">bis</span>
                     <input type="text" id="range_end" placeholder="Ende (z.B. 020)" class="form-control" style="flex: 1;">
                 </div>
-                <small style="display:block; color:#666; margin-bottom: 10px;">Tipp: Die Anzahl der Ziffern im "Ende"-Feld bestimmt die führenden Nullen (z.B. Ende "050" macht aus Start "1" einen "001").</small>
+                <small style="display:block; color:#666; margin-bottom: 10px;">Tipp: Der Präfix ist optional. Die Anzahl der Ziffern im "Ende"-Feld bestimmt die führenden Nullen (z.B. Ende "050" macht aus Start "1" einen "001").</small>
                 <button type="button" class="btn btn-secondary" onclick="generateCodeRange()">Bereich generieren & einfügen</button>
             </div>
 
@@ -852,9 +852,9 @@
                     </select>
                     <small style="display:block; color:#666;">Wählen Sie einen Medientyp aus zur Klassifizierung.</small>
                 </div>
-                <h3>Kategorie/Typ:</h3>
+                <h3>Kategorie/Typ/Fach:</h3>
                 <div class="form-group">
-                    <input type="text" name="library_category" id="library_category" placeholder="z.B. Belletristik, Sachbücher, Nachschlagewerke, etc.">
+                    <input type="text" name="library_category" id="library_category" placeholder="z.B. Belletristik, Sachbücher, Nachschlagewerke, etc. (optional)">
                     <small style="display:block; color:#666;">Geben Sie hier eine beliebige Kategorie ein zur freien Klassifizierung.</small>
                 </div>
             </div>
@@ -1024,6 +1024,90 @@
 <script>
     const libraryModuleEnabled = {{ 'true' if library_module_enabled else 'false' }};
 
+    function getFocusableFormFields(form) {
+        if (!form) return [];
+        return Array.from(form.querySelectorAll('input, select, textarea, button'))
+            .filter((element) => {
+                if (element.disabled || element.getAttribute('aria-hidden') === 'true') return false;
+                const style = window.getComputedStyle(element);
+                if (style.display === 'none' || style.visibility === 'hidden') return false;
+                const tagName = element.tagName.toLowerCase();
+                const type = (element.type || '').toLowerCase();
+                return tagName !== 'button' || type !== 'button';
+            });
+    }
+
+    function focusNextFormField(currentField) {
+        const form = currentField && currentField.form ? currentField.form : null;
+        const fields = getFocusableFormFields(form || document);
+        const currentIndex = fields.indexOf(currentField);
+
+        if (currentIndex >= 0) {
+            for (let i = currentIndex + 1; i < fields.length; i++) {
+                const nextField = fields[i];
+                const nextStyle = window.getComputedStyle(nextField);
+                if (nextStyle.display !== 'none' && nextStyle.visibility !== 'hidden') {
+                    nextField.focus();
+                    if (nextField.tagName.toLowerCase() === 'select') {
+                        nextField.click();
+                    }
+                    return true;
+                }
+            }
+        }
+
+        if (form) {
+            const submitButton = form.querySelector('button[type="submit"]');
+            if (submitButton) {
+                submitButton.focus();
+                return true;
+            }
+        }
+
+        return false;
+    }
+
+    function handleIsbnLookupFromScanner() {
+        const isbnField = document.getElementById('isbn');
+        if (!isbnField) return false;
+
+        const normalizedIsbn = typeof normalizeIsbnClient === 'function' ? normalizeIsbnClient(isbnField.value) : isbnField.value.trim();
+        if (!normalizedIsbn) return false;
+
+        if (typeof updateIsbnLiveValidation === 'function') {
+            updateIsbnLiveValidation();
+        }
+
+        if (typeof fetchBookInfo === 'function') {
+            fetchBookInfo('upload');
+        }
+
+        return true;
+    }
+
+    document.addEventListener('DOMContentLoaded', function () {
+        document.querySelectorAll('form').forEach(function (form) {
+            form.addEventListener('keydown', function (event) {
+                const target = event.target;
+                if (event.key !== 'Enter') return;
+                if (!target || target.tagName === 'TEXTAREA' && !event.shiftKey) return;
+                const tagName = target.tagName.toLowerCase();
+                const type = (target.type || '').toLowerCase();
+                if (!['input', 'select', 'textarea'].includes(tagName)) return;
+                if (['button', 'submit', 'reset', 'file', 'checkbox', 'radio', 'hidden'].includes(type)) return;
+
+                event.preventDefault();
+
+                if (target.id === 'isbn' || target.name === 'isbn') {
+                    handleIsbnLookupFromScanner();
+                    return;
+                }
+
+                focusNextFormField(target);
+            });
+        });
+    });
+
     // Function to check if a file is a video
     function isVideoFile(filename) {
         const videoExtensions = ['.mp4', '.mov', '.avi', '.mkv', '.webm', '.flv', '.m4v', '.3gp'];
@@ -1195,7 +1279,7 @@
         let generatedCodes = [];
         for (let i = start; i <= end; i++) {
             let numStr = i.toString().padStart(paddingLength, '0');
-            generatedCodes.push(`${prefix}${numStr}`);
+            generatedCodes.push(prefix ? `${prefix}${numStr}` : numStr);
         }
 
         const codeField = document.getElementById('code_4');
@@ -1385,10 +1469,32 @@
             scanModeSelect.addEventListener('change', toggleScanMode);
         }
 
-        // 4. ISBN Live-Validierung
+        // 4. ISBN Live-Validierung und automatische Abfrage nach Scan/Enter
         const isbnInput = document.getElementById('isbn');
-        if (isbnInput && typeof updateIsbnLiveValidation === 'function') {
-            isbnInput.addEventListener('input', updateIsbnLiveValidation);
+        if (isbnInput) {
+            if (typeof updateIsbnLiveValidation === 'function') {
+                isbnInput.addEventListener('input', updateIsbnLiveValidation);
+            }
+
+            let isbnLookupTimer = null;
+            isbnInput.addEventListener('input', function () {
+                clearTimeout(isbnLookupTimer);
+                const normalizedIsbn = typeof normalizeIsbnClient === 'function' ? normalizeIsbnClient(isbnInput.value) : isbnInput.value.trim();
+                if (normalizedIsbn) {
+                    isbnLookupTimer = setTimeout(function () {
+                        handleIsbnLookupFromScanner();
+                    }, 250);
+                }
+            });
+
+            isbnInput.addEventListener('change', function () {
+                if (typeof normalizeIsbnClient === 'function') {
+                    const normalizedIsbn = normalizeIsbnClient(isbnInput.value);
+                    if (normalizedIsbn) {
+                        handleIsbnLookupFromScanner();
+                    }
+                }
+            });
         }
     });
     // Load predefined filter values for dropdowns