frontend/src/pages/WorkflowEditorPage.jsx

@@ -77,11 +77,23 @@ export default function WorkflowEditorPage() {
   const [placeholderPickerTarget, setPlaceholderPickerTarget] = useState('end') // 'end' | 'inline'
   const endNodeTextareaRef = useRef(null)
   const inlineTemplateTextareaRef = useRef(null)
+  const [hasUnsavedChanges, setHasUnsavedChanges] = useState(false)
 
   // Toast & Confirm Dialog
   const [toast, setToast] = useState(null)
   const [confirmDialog, setConfirmDialog] = useState(null)
 
+  // Wrapped handlers to track unsaved changes
+  const handleNodesChange = useCallback((changes) => {
+    onNodesChange(changes)
+    setHasUnsavedChanges(true)
+  }, [onNodesChange])
+
+  const handleEdgesChange = useCallback((changes) => {
+    onEdgesChange(changes)
+    setHasUnsavedChanges(true)
+  }, [onEdgesChange])
+
   // Load available basis prompts for Analysis nodes
   useEffect(() => {
     async function loadPrompts() {
@@ -112,10 +124,26 @@ export default function WorkflowEditorPage() {
     setValidationWarnings(warnings)
   }, [nodes, edges])
 
+  // Warn on browser back/refresh if unsaved changes
+  useEffect(() => {
+    const handleBeforeUnload = (e) => {
+      if (hasUnsavedChanges) {
+        e.preventDefault()
+        e.returnValue = '' // Chrome requires returnValue to be set
+      }
+    }
+
+    window.addEventListener('beforeunload', handleBeforeUnload)
+    return () => window.removeEventListener('beforeunload', handleBeforeUnload)
+  }, [hasUnsavedChanges])
+
   // ── Handlers ──────────────────────────────────────────────────────────────
 
   const onConnect = useCallback(
-    (params) => setEdges((eds) => addEdge(params, eds)),
+    (params) => {
+      setEdges((eds) => addEdge(params, eds))
+      setHasUnsavedChanges(true)
+    },
     [setEdges]
   )
 
@@ -144,6 +172,7 @@ export default function WorkflowEditorPage() {
       }
     }
     setNodes((nds) => [...nds, base])
+    setHasUnsavedChanges(true)
   }
 
   const handleNodeUpdate = (nodeId, updates) => {
@@ -153,6 +182,7 @@ export default function WorkflowEditorPage() {
       console.log('📝 Nodes after update:', updated.find(n => n.id === nodeId))
       return updated
     })
+    setHasUnsavedChanges(true)
   }
 
   const handleDeleteNode = () => {
@@ -161,6 +191,7 @@ export default function WorkflowEditorPage() {
     setNodes((nds) => nds.filter((n) => n.id !== selectedNode.id))
     setEdges((eds) => eds.filter((e) => e.source !== selectedNode.id && e.target !== selectedNode.id))
     setSelectedNodeId(null)
+    setHasUnsavedChanges(true)
   }
 
   const handleSave = async () => {
@@ -217,6 +248,9 @@ export default function WorkflowEditorPage() {
         console.log('🚀 Navigating to:', `/workflow-editor/${result.id}`)
         navigate(`/workflow-editor/${result.id}`)
       }
+
+      // Clear unsaved changes flag after successful save
+      setHasUnsavedChanges(false)
     } catch (e) {
       console.error('❌ handleSave error:', e)
       setError(e.message)
@@ -275,6 +309,9 @@ export default function WorkflowEditorPage() {
       )
       nodeIdCounter = maxId + 1
       console.log('✅ Workflow loaded successfully, nodes:', loadedNodes.length, 'edges:', loadedEdges.length)
+
+      // Clear unsaved changes flag after successful load
+      setHasUnsavedChanges(false)
     } catch (e) {
       console.error('❌ loadWorkflow error:', e)
       setError(e.message)
@@ -296,14 +333,18 @@ export default function WorkflowEditorPage() {
   }
 
   const handleNew = () => {
-    if (confirm('Neuen Workflow erstellen? Ungespeicherte Änderungen gehen verloren.')) {
-      setNodes([])
-      setEdges([])
-      setCurrentPrompt(null)
-      setWorkflowName('Neuer Workflow')
-      setSelectedNodeId(null)
-      navigate('/workflow-editor/new')
+    if (hasUnsavedChanges) {
+      if (!confirm('Neuen Workflow erstellen? Ungespeicherte Änderungen gehen verloren.')) {
+        return
+      }
     }
+    setNodes([])
+    setEdges([])
+    setCurrentPrompt(null)
+    setWorkflowName('Neuer Workflow')
+    setSelectedNodeId(null)
+    setHasUnsavedChanges(false)
+    navigate('/workflow-editor/new')
   }
 
   const handleDelete = async () => {
@@ -328,6 +369,17 @@ export default function WorkflowEditorPage() {
     setExecutionResult(result)
   }
 
+  const handleBack = () => {
+    if (hasUnsavedChanges) {
+      const confirm = window.confirm(
+        'Du hast ungespeicherte Änderungen.\n\n' +
+        'Möchtest du wirklich zurück gehen? Alle Änderungen gehen verloren.'
+      )
+      if (!confirm) return
+    }
+    navigate('/admin/prompts')
+  }
+
   const handlePlaceholderSelect = (placeholderString) => {
     if (!selectedNode) return
 
@@ -392,14 +444,17 @@ export default function WorkflowEditorPage() {
     <div className="workflow-editor">
       {/* Toolbar */}
       <div className="workflow-toolbar">
-        <button className="btn-secondary" onClick={() => navigate('/admin/prompts')}>
+        <button className="btn-secondary" onClick={handleBack}>
           ← Zurück
         </button>
 
         <input
           type="text"
           value={workflowName}
-          onChange={(e) => setWorkflowName(e.target.value)}
+          onChange={(e) => {
+            setWorkflowName(e.target.value)
+            setHasUnsavedChanges(true)
+          }}
           placeholder="Interner Workflow-Name (Slug-Basis)"
           title="Technischer Name in der Datenbank. Den sichtbaren Titel für die KI-Analyse setzt du in der Start-Node."
           style={{ flex: 1, padding: '8px', borderRadius: '4px', border: '1px solid var(--border)' }}
@@ -498,8 +553,8 @@ export default function WorkflowEditorPage() {
             nodes={nodes}
             edges={edges}
             nodeTypes={nodeTypes}
-            onNodesChange={onNodesChange}
-            onEdgesChange={onEdgesChange}
+            onNodesChange={handleNodesChange}
+            onEdgesChange={handleEdgesChange}
             onConnect={onConnect}
             onNodeClick={onNodeClick}
           />