fix: incorrect phase reduction order

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

@@ -9,6 +9,7 @@ import styles from '../../VisProg.module.css';
 import { NodeReduces, NodesInPhase, NodeTypes} from '../NodeRegistry';
 import useFlowStore from '../VisProgStores';
 import { TextField } from '../../../../components/TextField';
+import LimitedConnectionCountHandle from "../components/CustomNodeHandles.tsx";
 
 /**
  * The default data dot a phase node
@@ -16,12 +17,15 @@ import { TextField } from '../../../../components/TextField';
  * @param droppable: whether this node is droppable from the drop bar (initialized as true)
  * @param children: ID's of children of this node
  * @param hasReduce: whether this node has reducing functionality (true by default)
+ * @param nextPhaseId:
  */
 export type PhaseNodeData = {
   label: string;
   droppable: boolean;
   children: string[];
   hasReduce: boolean;
+  nextPhaseId: string | "end" | null;
+  isFirstPhase: boolean;
 };
 
 export type PhaseNode = Node<PhaseNodeData>
@@ -50,9 +54,21 @@ export default function PhaseNode(props: NodeProps<PhaseNode>) {
             placeholder={"Phase ..."}
           />
         </div>
-        <Handle type="target" position={Position.Left} id="target"/>
+        <LimitedConnectionCountHandle
+          node_id={props.id}
+          type="target"
+          position={Position.Left}
+          connection_count={1}
+          id="target"
+        />
         <Handle type="target" position={Position.Bottom} id="norms"/>
-        <Handle type="source" position={Position.Right} id="source"/>
+        <LimitedConnectionCountHandle
+          node_id={props.id}
+          type="source"
+          position={Position.Right}
+          connection_count={1}
+          id="source"
+        />
       </div>
     </>
   );
@@ -65,8 +81,8 @@ export default function PhaseNode(props: NodeProps<PhaseNode>) {
  * @returns A collection of all reduced nodes in this phase, starting with this phases' reduced data.  
  */
 export function PhaseReduce(node: Node, nodes: Node[]) {
-    const thisnode = node as PhaseNode;
-    const data = thisnode.data as PhaseNodeData;
+    const thisNode = node as PhaseNode;
+    const data = thisNode.data as PhaseNodeData;
 
     // node typings that are not in phase
     const nodesNotInPhase: string[] = Object.entries(NodesInPhase)
@@ -85,8 +101,8 @@ export function PhaseReduce(node: Node, nodes: Node[]) {
 
     // Build the result object
     const result: Record<string, unknown> = {
-        id: thisnode.id,
-        label: data.label,
+      id: thisNode.id,
+      label: data.label,
     };
 
     nodesInPhase.forEach((type) => {
@@ -109,13 +125,19 @@ export function PhaseReduce(node: Node, nodes: Node[]) {
  * @param _sourceNodeId the source of the received connection
  */
 export function PhaseConnectionTarget(_thisNode: Node, _sourceNodeId: string) {
-  const node = _thisNode as PhaseNode
-  const data = node.data as PhaseNodeData
-  // we only add none phase nodes to the children
-  if (!(useFlowStore.getState().nodes.find((node) => node.id === _sourceNodeId && node.type === 'phase'))) {
-    data.children.push(_sourceNodeId)
-  }
+  const data = _thisNode.data as PhaseNodeData
 
+  const nodes = useFlowStore.getState().nodes;
+  const sourceNode = nodes.find((node) => node.id === _sourceNodeId)!
+  switch (sourceNode.type) {
+    case "phase": break;
+    case "start": data.isFirstPhase = true; break;
+    // we only add none phase or start nodes to the children
+    // endNodes cannot be the source of an outgoing connection
+    // so we don't need to cover them with a special case
+    // before handling the default behavior
+    default: data.children.push(_sourceNodeId); break;
+  }
 }
 
 /**
@@ -124,7 +146,19 @@ export function PhaseConnectionTarget(_thisNode: Node, _sourceNodeId: string) {
  * @param _targetNodeId the target of the created connection
  */
 export function PhaseConnectionSource(_thisNode: Node, _targetNodeId: string) {
-  // no additional connection logic exists yet
+  const data = _thisNode.data as PhaseNodeData
+  const nodes = useFlowStore.getState().nodes;
+
+  const targetNode = nodes.find((node) => node.id === _targetNodeId)
+  if (!targetNode) {throw new Error("Source node not found")}
+
+  // we set the nextPhaseId to the next target's id if the target is a phaseNode,
+  // or "end" if the target node is the end node
+  switch (targetNode.type) {
+    case 'phase': data.nextPhaseId = _targetNodeId; break;
+    case 'end': data.nextPhaseId = "end"; break;
+    default: break;
+  }
 }
 
 /**
@@ -133,9 +167,23 @@ export function PhaseConnectionSource(_thisNode: Node, _targetNodeId: string) {
  * @param _sourceNodeId the source of the disconnected connection
  */
 export function PhaseDisconnectionTarget(_thisNode: Node, _sourceNodeId: string) {
-  const node = _thisNode as PhaseNode
-  const data = node.data as PhaseNodeData
-  data.children = data.children.filter((child) => { if (child != _sourceNodeId) return child; });
+  const data = _thisNode.data as PhaseNodeData
+
+  const nodes = useFlowStore.getState().nodes;
+  const sourceNode = nodes.find((node) => node.id === _sourceNodeId)
+  const sourceType = sourceNode ? sourceNode.type : "deleted";
+  switch (sourceType) {
+    case "phase": break;
+    case "start": data.isFirstPhase = false; break;
+    // we only add none phase or start nodes to the children
+    // endNodes cannot be the source of an outgoing connection
+    // so we don't need to cover them with a special case
+    // before handling the default behavior
+    default:
+      data.children = data.children.filter((child) => { if (child != _sourceNodeId) return child; });
+      break;
+  }
+
 }
 
 /**
@@ -144,5 +192,12 @@ export function PhaseDisconnectionTarget(_thisNode: Node, _sourceNodeId: string)
  * @param _targetNodeId the target of the diconnected connection
  */
 export function PhaseDisconnectionSource(_thisNode: Node, _targetNodeId: string) {
-  // no additional connection logic exists yet
+  const data = _thisNode.data as PhaseNodeData
+  const nodes = useFlowStore.getState().nodes;
+
+  // if the target is a phase or end node set the nextPhaseId to null,
+  // as we are no longer connected to a subsequent phaseNode or to the endNode
+  if (nodes.some((node) => node.id === _targetNodeId && ['phase', 'end'].includes(node.type!))){
+    data.nextPhaseId = null;
+  }
 }