package org.simantics.district.network.profile;

import java.util.HashSet;
import java.util.List;
import java.util.Set;

import org.simantics.Simantics;
import org.simantics.db.ReadGraph;
import org.simantics.db.Resource;
import org.simantics.db.common.procedure.adapter.TransientCacheListener;
import org.simantics.db.common.request.ResourceRead;
import org.simantics.db.exception.DatabaseException;
import org.simantics.layer0.Layer0;
import org.simantics.scenegraph.INode;
import org.simantics.scenegraph.g2d.G2DSceneGraph;
import org.simantics.scenegraph.g2d.nodes.ConnectionNode;
import org.simantics.scenegraph.profile.EvaluationContext;
import org.simantics.scenegraph.profile.common.ProfileVariables;

public class ArrowLengthStyle extends ThrottledStyleBase<Double> {

	private static final Double PENDING = Double.NaN;

	@Override
	public Double calculateThrottledStyle(ReadGraph graph, Resource runtimeDiagram, Resource entry, Resource groupItem) throws DatabaseException {
		Resource diagram = graph.getSingleObject(groupItem, Layer0.getInstance(graph).PartOf);
		Set<Resource> edgesToUse = graph.syncRequest(new MidBranchEdgeSetRequest(diagram), TransientCacheListener.instance());
		if (!edgesToUse.contains(groupItem))
			return null;
		
		DiagramSettings ds = graph.syncRequest(new DiagramSettingsRequest(runtimeDiagram), TransientCacheListener.instance());
		// Prevent PendingVariableExceptions from coming through
		boolean wasSynchronous = graph.setSynchronous(true);
		try {
			if (ds.arrowLengthProperty.isPresent()) {
				Double length = Simantics.applySCLRead(graph, ds.arrowLengthProperty.get(), groupItem);
				return length != null ? length * ds.arrowLengthGain + ds.arrowLengthBias : null;
			}
			else {
				return null;
			}
		}
		finally {
			graph.setSynchronous(wasSynchronous);
		}
	}

	@Override
	public void applyThrottledStyleForNode(EvaluationContext observer, INode node, Double value) {
//		System.out.println("apply: " + node + " : " + value);
		ConnectionNode n = (ConnectionNode) node;
		if (value == PENDING) {
			((G2DSceneGraph)node.getRootNode()).setPending(node);
		} else {
			((G2DSceneGraph)node.getRootNode()).clearPending(node);
		}
		for (INode nn : n.getNodes())
			ProfileVariables.claimNodeProperty(nn, "arrowLength", value, observer);
	}

	@Override
	protected void cleanupStyleForNode(EvaluationContext evaluationContext, INode node) {
		((G2DSceneGraph)node.getRootNode()).clearPending(node);
		ConnectionNode n = (ConnectionNode) node;
		for (INode nn : n.getNodes())
			ProfileVariables.claimNodeProperty(nn, "arrowLength", null, evaluationContext);
	}

	private static final class MidBranchEdgeSetRequest extends ResourceRead<Set<Resource>> {
		private MidBranchEdgeSetRequest(Resource resource) {
			super(resource);
		}
	
		@Override
		public Set<Resource> perform(ReadGraph graph) throws DatabaseException {
			List<Resource> edges = Simantics.applySCL("Simantics/District/Algorithm", "midBranchEdges", graph, resource);
			return new HashSet<>(edges);
		}
	}

}