Fix Vorlagen editor: working preview tab and improved layout

- Fix preview bug: preview event handlers were never attached when
  Summernote failed to load (fallback returned early at line 240)
- Restructure layout with Bootstrap tabs (Editor | Vorschau) instead
  of stacked editor+hidden preview
- Preview loads automatically when switching to the Vorschau tab
- Editor content getter works in all modes (Summernote, code, fallback)
- Editor now uses full viewport height for more editing space
- Variables sidebar gets 3 cols (was 4) giving editor 9 cols (was 8)

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

app/templates/stiftung/vorlage_editor.html

@@ -9,13 +9,13 @@
 <style>
     .preview-frame {
         width: 100%;
-        height: 580px;
+        height: 75vh;
         border: 1px solid #dee2e6;
         border-radius: 4px;
         background: #fff;
     }
     .var-list {
-        max-height: 400px;
+        max-height: 55vh;
         overflow-y: auto;
     }
     .var-item {
@@ -31,7 +31,7 @@
     }
     .code-editor-textarea {
         width: 100%;
-        height: 520px;
+        height: 70vh;
         font-family: 'SFMono-Regular', Consolas, 'Liberation Mono', Menlo, monospace;
         font-size: 13px;
         line-height: 1.5;
@@ -50,6 +50,11 @@
         border-color: #86b7fe;
         box-shadow: 0 0 0 .25rem rgba(13,110,253,.25);
     }
+    #tab-vorschau .preview-loading {
+        text-align: center;
+        padding: 80px 0;
+        color: #6c757d;
+    }
 </style>
 {% endblock %}
 
@@ -66,7 +71,7 @@
             </div>
             <div class="d-flex gap-2">
                 <a href="{% url 'stiftung:vorlagen_liste' %}" class="btn btn-sm btn-outline-secondary">
-                    <i class="fas fa-arrow-left me-1"></i>Zurück zur Liste
+                    <i class="fas fa-arrow-left me-1"></i>Zurück
                 </a>
                 {% if hat_original %}
                 <form method="post" action="{% url 'stiftung:vorlage_zuruecksetzen' pk=vorlage.pk %}"
@@ -82,42 +87,42 @@
     </div>
 </div>
 
-<div class="row">
+<!-- Tabs: Editor | Vorschau -->
-    <!-- Editor (links) -->
+<ul class="nav nav-tabs mb-3" role="tablist">
-    <div class="col-lg-8">
+    <li class="nav-item">
-        <form method="post" id="editor-form">
+        <button class="nav-link active" data-bs-toggle="tab" data-bs-target="#tab-editor" type="button" role="tab">
-            {% csrf_token %}
+            <i class="fas fa-code me-1"></i>Editor
-            <div class="d-flex gap-2 mb-2 justify-content-end">
+        </button>
-                <button type="button" class="btn btn-sm btn-outline-secondary" id="btn-preview">
+    </li>
+    <li class="nav-item">
+        <button class="nav-link" data-bs-toggle="tab" data-bs-target="#tab-vorschau" type="button" role="tab" id="btn-tab-vorschau">
             <i class="fas fa-eye me-1"></i>Vorschau
         </button>
-                <button type="submit" class="btn btn-sm btn-primary">
+    </li>
+    <li class="nav-item ms-auto">
+        <button type="submit" form="editor-form" class="btn btn-sm btn-primary my-1">
             <i class="fas fa-save me-1"></i>Speichern
         </button>
-            </div>
+    </li>
+</ul>
+
+<div class="tab-content">
+    <!-- Editor Tab -->
+    <div class="tab-pane fade show active" id="tab-editor" role="tabpanel">
+        <div class="row">
+            <div class="{% if variablen %}col-lg-9{% else %}col-12{% endif %}">
+                <form method="post" id="editor-form">
+                    {% csrf_token %}
                     <textarea name="html_inhalt" id="code-editor"{% if use_code_editor %} class="code-editor-textarea"{% endif %}>{{ vorlage.html_inhalt }}</textarea>
                     <script type="application/json" id="vorlage-html-inhalt">{{ html_inhalt_json }}</script>
                 </form>
-
-        <!-- Vorschau-Bereich (initial versteckt) -->
-        <div id="preview-area" class="mt-3" style="display:none">
-            <div class="d-flex align-items-center justify-content-between mb-2">
-                <strong>Vorschau <span class="badge bg-secondary">Beispieldaten</span></strong>
-                <button type="button" class="btn btn-sm btn-outline-secondary" id="btn-close-preview">
-                    <i class="fas fa-times me-1"></i>Vorschau schließen
-                </button>
             </div>
-            <iframe id="preview-frame" class="preview-frame" title="Vorschau"></iframe>
-        </div>
-    </div>
-
-    <!-- Seitenleiste (rechts) -->
-    <div class="col-lg-4">
             {% if variablen %}
+            <div class="col-lg-3">
                 <div class="card shadow mb-3">
                     <div class="card-header py-2">
-                <h6 class="m-0 font-weight-bold text-primary">
+                        <h6 class="m-0 fw-bold text-primary small">
-                    <i class="fas fa-code me-1"></i>Verfügbare Variablen
+                            <i class="fas fa-code me-1"></i>Variablen
                         </h6>
                         <small class="text-muted">Klick zum Einfügen</small>
                     </div>
@@ -138,11 +143,9 @@
                         </div>
                     </div>
                 </div>
-        {% endif %}
-
                 <div class="card shadow">
                     <div class="card-header py-2">
-                <h6 class="m-0 font-weight-bold text-secondary">
+                        <h6 class="m-0 fw-bold text-secondary small">
                             <i class="fas fa-info-circle me-1"></i>Info
                         </h6>
                     </div>
@@ -160,6 +163,18 @@
                     </div>
                 </div>
             </div>
+            {% endif %}
+        </div>
+    </div>
+
+    <!-- Vorschau Tab -->
+    <div class="tab-pane fade" id="tab-vorschau" role="tabpanel">
+        <div class="preview-loading" id="preview-loading">
+            <i class="fas fa-spinner fa-spin fa-2x mb-2 d-block"></i>
+            Vorschau wird geladen...
+        </div>
+        <iframe id="preview-frame" class="preview-frame" title="Vorschau" style="display:none"></iframe>
+    </div>
 </div>
 {% endblock %}
 
@@ -180,15 +195,22 @@
 
     var useCodeEditor = {{ use_code_editor|yesno:"true,false" }};
     var editor = document.getElementById('code-editor');
+    var summernoteActive = false;
 
-    // Code-Editor-Modus: Plain textarea fuer vollstaendige HTML-Dokumente
+    // Returns current HTML content regardless of editor mode
-    // (Serienbrief-Vorlagen mit DOCTYPE, Template-Tags usw.)
+    function getEditorContent() {
+        if (summernoteActive) {
+            return $('#code-editor').summernote('code');
+        }
+        return editor.value;
+    }
+
+    // ---- Editor setup ----
     if (useCodeEditor) {
+        // Plain textarea for full HTML documents (Serienbrief)
         if (initialContent) {
             editor.value = initialContent;
         }
-
-        // Tab-Taste einfügen statt Fokus wechseln
         editor.addEventListener('keydown', function(e) {
             if (e.key === 'Tab') {
                 e.preventDefault();
@@ -198,8 +220,7 @@
                 this.selectionStart = this.selectionEnd = start + 4;
             }
         });
-
+        // Variable insertion for code editor
-        // Variablen einfügen bei Klick
         document.querySelectorAll('.var-item').forEach(function(row) {
             row.addEventListener('click', function() {
                 var varName = this.getAttribute('data-var');
@@ -210,37 +231,8 @@
                 editor.focus();
             });
         });
-
+    } else if (typeof $ !== 'undefined' && typeof $.fn.summernote !== 'undefined') {
-        // Vorschau
+        // Summernote WYSIWYG for HTML fragment templates
-        var previewArea = document.getElementById('preview-area');
-        var previewFrame = document.getElementById('preview-frame');
-        document.getElementById('btn-preview').addEventListener('click', function() {
-            var formData = new FormData();
-            formData.append('html_inhalt', editor.value);
-            formData.append('csrfmiddlewaretoken', document.querySelector('[name=csrfmiddlewaretoken]').value);
-            fetch('{% url "stiftung:vorlage_vorschau" pk=vorlage.pk %}', { method: 'POST', body: formData })
-                .then(function(r) { return r.text(); })
-                .then(function(html) {
-                    previewFrame.srcdoc = html;
-                    previewArea.style.display = 'block';
-                    previewArea.scrollIntoView({behavior: 'smooth'});
-                })
-                .catch(function(err) { alert('Vorschau fehlgeschlagen: ' + err); });
-        });
-        document.getElementById('btn-close-preview').addEventListener('click', function() {
-            previewArea.style.display = 'none';
-        });
-
-        return;  // Skip Summernote initialization
-    }
-
-    if (typeof $ === 'undefined' || typeof $.fn.summernote === 'undefined') {
-        // Fallback: Summernote nicht geladen — Textarea sichtbar lassen
-        if (editor) { editor.style.height = '520px'; editor.style.fontFamily = 'monospace'; editor.style.fontSize = '13px'; }
-        return;
-    }
-
-    // Summernote initialisieren (für HTML-Fragment-Vorlagen: E-Mail, PDF-Fragmente)
         $('#code-editor').summernote({
             lang: 'de-DE',
             height: 520,
@@ -259,52 +251,80 @@
                 }
             }
         });
+        summernoteActive = true;
 
-    // Variablen einfügen bei Klick
+        // Variable insertion for Summernote
         document.querySelectorAll('.var-item').forEach(function(row) {
             row.addEventListener('click', function() {
-            const varName = this.getAttribute('data-var');
+                var varName = this.getAttribute('data-var');
-            const placeholder = String.fromCharCode(123,123) + ' ' + varName + ' ' + String.fromCharCode(125,125);
+                var placeholder = String.fromCharCode(123,123) + ' ' + varName + ' ' + String.fromCharCode(125,125);
                 $('#code-editor').summernote('focus');
                 $('#code-editor').summernote('insertText', placeholder);
             });
         });
 
-    // Vorschau
+        // Sync Summernote to textarea on form submit
-    const previewArea = document.getElementById('preview-area');
+        document.getElementById('editor-form').addEventListener('submit', function() {
-    const previewFrame = document.getElementById('preview-frame');
+            document.querySelector('textarea[name=html_inhalt]').value = getEditorContent();
-    const btnPreview = document.getElementById('btn-preview');
+        });
-    const btnClosePreview = document.getElementById('btn-close-preview');
+    } else {
+        // Fallback: Summernote not loaded — style textarea as code editor
+        if (editor) {
+            editor.style.height = '70vh';
+            editor.style.fontFamily = "'SFMono-Regular', Consolas, monospace";
+            editor.style.fontSize = '13px';
+            editor.style.padding = '12px';
+            editor.style.background = '#f8f9fa';
+        }
+        if (initialContent) {
+            editor.value = initialContent;
+        }
+        // Variable insertion for plain textarea fallback
+        document.querySelectorAll('.var-item').forEach(function(row) {
+            row.addEventListener('click', function() {
+                var varName = this.getAttribute('data-var');
+                var placeholder = String.fromCharCode(123,123) + ' ' + varName + ' ' + String.fromCharCode(125,125);
+                var start = editor.selectionStart;
+                editor.value = editor.value.substring(0, start) + placeholder + editor.value.substring(editor.selectionEnd);
+                editor.selectionStart = editor.selectionEnd = start + placeholder.length;
+                editor.focus();
+            });
+        });
+    }
 
-    btnPreview.addEventListener('click', function() {
+    // ---- Preview (always set up, independent of editor mode) ----
-        const content = $('#code-editor').summernote('code');
+    var previewFrame = document.getElementById('preview-frame');
-        const formData = new FormData();
+    var previewLoading = document.getElementById('preview-loading');
+    var previewLoaded = false;
+
+    function loadPreview() {
+        var content = getEditorContent();
+        var formData = new FormData();
         formData.append('html_inhalt', content);
         formData.append('csrfmiddlewaretoken', document.querySelector('[name=csrfmiddlewaretoken]').value);
 
+        previewLoading.style.display = 'block';
+        previewFrame.style.display = 'none';
+
         fetch('{% url "stiftung:vorlage_vorschau" pk=vorlage.pk %}', {
             method: 'POST',
             body: formData,
         })
-        .then(r => r.text())
+        .then(function(r) { return r.text(); })
-        .then(html => {
+        .then(function(html) {
             previewFrame.srcdoc = html;
-            previewArea.style.display = 'block';
+            previewFrame.style.display = 'block';
-            previewArea.scrollIntoView({behavior: 'smooth'});
+            previewLoading.style.display = 'none';
+            previewLoaded = true;
         })
-        .catch(err => alert('Vorschau fehlgeschlagen: ' + err));
+        .catch(function(err) {
+            previewLoading.innerHTML = '<i class="fas fa-exclamation-triangle text-danger fa-2x mb-2 d-block"></i>Vorschau fehlgeschlagen: ' + err;
         });
+    }
 
-    btnClosePreview.addEventListener('click', function() {
+    // Load preview when switching to the Vorschau tab
-        previewArea.style.display = 'none';
+    document.getElementById('btn-tab-vorschau').addEventListener('shown.bs.tab', function() {
-    });
+        loadPreview();
-
-    // Formular-Submit: Summernote-Inhalt in Textarea schreiben
-    document.getElementById('editor-form').addEventListener('submit', function() {
-        // Summernote schreibt den Inhalt automatisch in die Textarea beim Submit
-        // Sicherheitshalber explizit synchronisieren:
-        const content = $('#code-editor').summernote('code');
-        document.querySelector('textarea[name=html_inhalt]').value = content;
     });
 })();
 </script>