//in ClusterGraph??
//is not yet recursive!!!
node collapseCluster(ClusterGraph& CG, cluster c, Graph& G)
{
	OGDF_ASSERT(c->cCount() == 0)

	ListIterator<node> its;
	SListPure<node> collaps;

	//we should check here if not empty
	node robinson = (*(c->nBegin()));

	for (its = c->nBegin(); its.valid(); its++)
		collaps.pushBack(*its);

	CG.collaps(collaps, G);

	if (c != CG.rootCluster())
		CG.delCluster(c);

	return robinson;
}
// Recursive call for testing c-planarity of the clustered graph
// that is induced by cluster act
bool CconnectClusterPlanar::planarityTest(
	ClusterGraph &C,
	cluster &act,
	Graph &G)
{
	// Test children first
	ListConstIterator<cluster> it;
	for (it = act->cBegin(); it.valid();)
	{
		ListConstIterator<cluster> succ = it.succ();
		cluster next = (*it);
		if (!planarityTest(C,next,G))
			return false;
		it = succ;
	}

	// Get induced subgraph of cluster act and test it for planarity

	List<node> subGraphNodes;
	for (node s : act->nodes)
		subGraphNodes.pushBack(s);

	Graph subGraph;
	NodeArray<node> table;
	inducedSubGraph(G,subGraphNodes.begin(),subGraph,table);


	// Introduce super sink and add edges corresponding
	// to outgoing edges of the cluster

	node superSink = subGraph.newNode();
	EdgeArray<node> outgoingTable(subGraph,nullptr);


	for (node w : act->nodes)
	{
		//adjEntry adj = w->firstAdj();
		for(adjEntry adj : w->adjEntries)
		{
			edge e = adj->theEdge();
			edge cor = nullptr;
			if (table[e->source()] == nullptr) // edge is connected to a node outside the cluster
			{
				cor = subGraph.newEdge(table[e->target()],superSink);
				outgoingTable[cor] = e->source();
			}
			else if (table[e->target()] == nullptr) // dito
			{
				cor = subGraph.newEdge(table[e->source()],superSink);
				outgoingTable[cor] = e->target();
			}

			// else edge connects two nodes of the cluster
		}
	}
	if (superSink->degree() == 0) // root cluster is not connected to outside clusters
	{
		subGraph.delNode(superSink);
		superSink = nullptr;
	}


	bool cPlanar = preparation(subGraph,act,superSink);


	if (cPlanar && act != C.rootCluster())
	{
		// Remove induced subgraph and the cluster act.
		// Replace it by a wheel graph
		while (!subGraphNodes.empty())
		{
			node w = subGraphNodes.popFrontRet();
//			C.unassignNode(w);
			G.delNode(w);
		}

		cluster parent = act->parent();

		if (superSink && m_clusterPQTree[act])
			constructWheelGraph(C,G,parent,m_clusterPQTree[act],outgoingTable);

		C.delCluster(act);
		if (m_clusterPQTree[act] != nullptr) // if query necessary for clusters with just one child
		{
			m_clusterPQTree[act]->emptyAllPertinentNodes();
			delete m_clusterPQTree[act];
		}

	}
	else if (!cPlanar)
		{
			m_errorCode = nonCPlanar;
		}//if not cplanar

	return cPlanar;

}