src/pages/VisProgPage/visualProgrammingUI/HandleRuleLogic.ts

@@ -108,3 +108,15 @@ export function useHandleRules(
     return evaluateRules(targetRules, connection, context);
   };
 }
+
+export function validateConnectionWithRules(
+  connection: Connection,
+  context: ConnectionContext
+): RuleResult {
+  const rules = useFlowStore.getState().getTargetRules(
+    connection.target!,
+    connection.targetHandle!
+  );
+
+  return evaluateRules(rules,connection, context);
+}

src/pages/VisProgPage/visualProgrammingUI/VisProgStores.tsx

@@ -9,6 +9,7 @@ import {
   type XYPosition,
 } from '@xyflow/react';
 import '@xyflow/react/dist/style.css';
+import {type ConnectionContext, validateConnectionWithRules} from "./HandleRuleLogic.ts";
 import type { FlowState } from './VisProgTypes';
 import {
   NodeDefaults,
@@ -129,7 +130,41 @@ const useFlowStore = create<FlowState>(UndoRedo((set, get) => ({
    * Handles reconnecting an edge between nodes.
    */
   onReconnect: (oldEdge, newConnection) => {
-    get().edgeReconnectSuccessful = true;
+
+    function createContext(
+      source: {id: string, handleId: string},
+      target: {id: string, handleId: string}
+    ) : ConnectionContext {
+      const edges = get().edges;
+      const targetConnections = edges.filter(edge => edge.target === target.id && edge.targetHandle === target.handleId).length
+      return {
+        connectionCount: targetConnections,
+        source: source,
+        target: target
+      }
+    }
+
+    // connection validation
+    const context: ConnectionContext = oldEdge.source === newConnection.source
+      ? createContext({id: newConnection.source, handleId: newConnection.sourceHandle!}, {id: newConnection.target, handleId: newConnection.targetHandle!})
+      : createContext({id: newConnection.target, handleId: newConnection.targetHandle!}, {id: newConnection.source, handleId: newConnection.sourceHandle!});
+
+    const result = validateConnectionWithRules(
+      newConnection,
+      context
+    );
+
+    if (!result.isSatisfied) {
+      set({
+        edges: get().edges.map(e =>
+          e.id === oldEdge.id ? oldEdge : e
+        ),
+      });
+      return;
+    }
+
+    // further reconnect logic
+    set({ edgeReconnectSuccessful: true });
     set({ edges: reconnectEdge(oldEdge, newConnection, get().edges) });
 
     // We make sure to perform any required data updates on the newly reconnected nodes