feat: [US-032] - Display conditions on edges

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

src/app/editor/[projectId]/FlowchartEditor.tsx

@@ -14,6 +14,7 @@ import ReactFlow, {
   Node,
   Edge,
   NodeTypes,
+  EdgeTypes,
   MarkerType,
   NodeMouseHandler,
   EdgeMouseHandler,
@@ -24,6 +25,7 @@ import Toolbar from '@/components/editor/Toolbar'
 import DialogueNode from '@/components/editor/nodes/DialogueNode'
 import ChoiceNode from '@/components/editor/nodes/ChoiceNode'
 import VariableNode from '@/components/editor/nodes/VariableNode'
+import ConditionalEdge from '@/components/editor/edges/ConditionalEdge'
 import ContextMenu, { ContextMenuType } from '@/components/editor/ContextMenu'
 import ConditionEditor from '@/components/editor/ConditionEditor'
 import type { FlowchartData, FlowchartNode, FlowchartEdge, Condition } from '@/types/flowchart'
@@ -65,7 +67,7 @@ function toReactFlowEdges(edges: FlowchartEdge[]): Edge[] {
     target: edge.target,
     targetHandle: edge.targetHandle,
     data: edge.data,
-    type: 'smoothstep',
+    type: 'conditional',
     markerEnd: {
       type: MarkerType.ArrowClosed,
     },
@@ -84,6 +86,14 @@ function FlowchartEditorInner({ initialData }: FlowchartEditorProps) {
     []
   )
 
+  // Define custom edge types - memoized to prevent re-renders
+  const edgeTypes: EdgeTypes = useMemo(
+    () => ({
+      conditional: ConditionalEdge,
+    }),
+    []
+  )
+
   const { getViewport, screenToFlowPosition } = useReactFlow()
 
   const [contextMenu, setContextMenu] = useState<ContextMenuState>(null)
@@ -105,7 +115,7 @@ function FlowchartEditorInner({ initialData }: FlowchartEditorProps) {
         target: params.target,
         sourceHandle: params.sourceHandle,
         targetHandle: params.targetHandle,
-        type: 'smoothstep',
+        type: 'conditional',
         markerEnd: {
           type: MarkerType.ArrowClosed,
         },
@@ -376,6 +386,7 @@ function FlowchartEditorInner({ initialData }: FlowchartEditorProps) {
           nodes={nodes}
           edges={edges}
           nodeTypes={nodeTypes}
+          edgeTypes={edgeTypes}
           onNodesChange={onNodesChange}
           onEdgesChange={onEdgesChange}
           onEdgesDelete={onEdgesDelete}

src/components/editor/edges/ConditionalEdge.tsx

@@ -0,0 +1,71 @@
+'use client'
+
+import {
+  BaseEdge,
+  EdgeLabelRenderer,
+  EdgeProps,
+  getSmoothStepPath,
+} from 'reactflow'
+import type { Condition } from '@/types/flowchart'
+
+type ConditionalEdgeData = {
+  condition?: Condition
+}
+
+export default function ConditionalEdge({
+  id,
+  sourceX,
+  sourceY,
+  targetX,
+  targetY,
+  sourcePosition,
+  targetPosition,
+  data,
+  markerEnd,
+  selected,
+}: EdgeProps<ConditionalEdgeData>) {
+  const [edgePath, labelX, labelY] = getSmoothStepPath({
+    sourceX,
+    sourceY,
+    sourcePosition,
+    targetX,
+    targetY,
+    targetPosition,
+  })
+
+  const hasCondition = !!data?.condition
+
+  // Format condition as readable label
+  const conditionLabel = hasCondition
+    ? `${data.condition!.variableName} ${data.condition!.operator} ${data.condition!.value}`
+    : null
+
+  return (
+    <>
+      <BaseEdge
+        id={id}
+        path={edgePath}
+        markerEnd={markerEnd}
+        style={{
+          strokeDasharray: hasCondition ? '5 5' : undefined,
+          stroke: selected ? '#3b82f6' : hasCondition ? '#f59e0b' : '#64748b',
+          strokeWidth: selected ? 2 : 1.5,
+        }}
+      />
+      {conditionLabel && (
+        <EdgeLabelRenderer>
+          <div
+            style={{
+              position: 'absolute',
+              transform: `translate(-50%, -50%) translate(${labelX}px,${labelY}px)`,
+              pointerEvents: 'all',
+            }}
+            className="rounded border border-amber-300 bg-amber-50 px-2 py-0.5 text-xs font-medium text-amber-800 dark:border-amber-600 dark:bg-amber-900 dark:text-amber-200"
+          >
+            {conditionLabel}
+          </div>
+        </EdgeLabelRenderer>
+      )}
+    </>
+  )
+}