src/pages/VisProgPage/visualProgrammingUI/nodes/InferredBeliefNode.tsx

@@ -2,11 +2,12 @@ import {
   type NodeProps,
   Position,
   type Node,
-  getConnectedEdges
+  getConnectedEdges, getOutgoers
 } from '@xyflow/react';
 import {useState} from "react";
 import { Toolbar } from '../components/NodeComponents.tsx';
 import styles from '../../VisProg.module.css';
+import {type HandleRule, type RuleResult, ruleResult} from "../HandleRuleLogic.ts";
 import {BeliefReduce} from "./BeliefReduce.ts";
 import switchStyles from './InferredBeliefNode.module.css';
 import {MultiConnectionHandle, SingleConnectionHandle} from "../components/RuleBasedHandle.tsx";
@@ -100,6 +101,30 @@ export function InferredBeliefDisconnectionSource(_thisNode: Node, _targetNodeId
   // no additional connection logic exists yet
 }
 
+/**
+ * This rule makes it impossible to connect Inferred belief nodes
+ * if the connection would create a looping connection between inferred beliefs
+ */
+const noBeliefCycles : HandleRule = (connection, _): RuleResult => {
+  const { nodes, edges }  = useFlowStore.getState();
+  function checkForCycle(targetNodeId: string, current: string) : RuleResult {
+    const outgoingBeliefs = getOutgoers({id: current}, nodes, edges).filter(node => node.type === 'inferred_belief');
+    if (outgoingBeliefs.length === 0) return ruleResult.satisfied;
+    if (outgoingBeliefs.some(node => node.id === targetNodeId)) return ruleResult
+      .notSatisfied("Cyclical connection exists between inferred beliefs");
+
+    const next = outgoingBeliefs.map(node => checkForCycle(targetNodeId, node.id)).find(result => !result.isSatisfied);
+    return next
+      ? next
+      : ruleResult.satisfied;
+  }
+
+  return connection.source === connection.target
+    ? ruleResult.notSatisfied("Cyclical connection exists between inferred beliefs")
+    : checkForCycle(connection.source, connection.target);
+}
+
+
 /**
  * Defines how a BasicBelief node should be rendered
  * @param props - Node properties provided by React Flow, including `id` and `data`.
@@ -144,14 +169,17 @@ export default function InferredBeliefNode(props: NodeProps<InferredBeliefNode>)
         {/* outgoing connections */}
         <MultiConnectionHandle type="source" position={Position.Right} id="source" rules={[
           allowOnlyConnectionsFromType(["norm", "trigger"]),
+          noBeliefCycles
         ]}/>
 
         {/* incoming connections */}
         <SingleConnectionHandle type="target" position={Position.Left} style={{top: '30%'}} id="beliefLeft" rules={[
           allowOnlyConnectionsFromType(["basic_belief", "inferred_belief"]),
+          noBeliefCycles
         ]}/>
         <SingleConnectionHandle type="target" position={Position.Left} style={{top: '70%'}} id="beliefRight" rules={[
           allowOnlyConnectionsFromType(["basic_belief", "inferred_belief"]),
+          noBeliefCycles
         ]}/>
       </div>
     </>