package org.simantics.district.network.profile;

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.district.network.ontology.DistrictNetworkResource;
import org.simantics.layer0.Layer0;
import org.simantics.scenegraph.INode;
import org.simantics.scenegraph.g2d.G2DSceneGraph;
import org.simantics.scenegraph.g2d.nodes.SingleElementNode;
import org.simantics.scenegraph.profile.EvaluationContext;
import org.simantics.scenegraph.profile.common.ProfileVariables;
import org.simantics.scl.runtime.function.Function;
import org.simantics.scl.runtime.function.FunctionImpl1;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

public class VertexSymbolStyle extends ThrottledStyleBase<String> {

	private static final Logger LOGGER = LoggerFactory.getLogger(VertexSymbolStyle.class);
	
	@SuppressWarnings({ "rawtypes", "unchecked" })
	@Override
	public String calculateThrottledStyle(ReadGraph graph, Resource runtimeDiagram, Resource entry, Resource groupItem) throws DatabaseException {
		// Prevent PendingVariableExceptions from coming through
		boolean wasSynchronous = graph.setSynchronous(true);
		try {
			Function symbolFunction = getSymbolFunction(graph, entry);
			if (symbolFunction == null)
				return null;
			
			try {
				return (String) Simantics.applySCLRead(graph, symbolFunction, groupItem);
			} catch (Exception e) {
				LOGGER.error("Getting dynamic symbol for " + groupItem + " (" + graph.getPossibleRelatedValue(groupItem, Layer0.getInstance(graph).HasName) + ") failed", e);
				return null;
			}
		}
		finally {
			graph.setSynchronous(wasSynchronous);
		}
	}

	@SuppressWarnings("rawtypes")
	protected static Function getSymbolFunction(ReadGraph graph, Resource entry) throws DatabaseException {
		// Cache function read for profile entry
		return graph.syncRequest(new SymbolFunctionRequest(entry), TransientCacheListener.<Function>instance());
	}

	@Override
	public void applyThrottledStyleForNode(EvaluationContext observer, INode node, String value) {
		SingleElementNode n = (SingleElementNode) node;
		for (INode nn : n.getNodes())
			ProfileVariables.claimNodeProperty(nn, "SVG", value, observer);
	}

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

	@SuppressWarnings("rawtypes")
	protected static final class SymbolFunctionRequest extends ResourceRead<Function> {
		protected static final Function CONST_NULL = new FunctionImpl1<Resource, String>() {
			@Override
			public String apply(Resource p0) {
				return null;
			}
		};
		
		public SymbolFunctionRequest(Resource entry) {
			super(entry);
		}

		@Override
		public Function perform(ReadGraph graph) throws DatabaseException {
			DistrictNetworkResource DN = DistrictNetworkResource.getInstance(graph);
			
			Function symbolFunction = (Function) graph.getPossibleRelatedValue2(resource, DN.HasSymbolFunction, resource);
			if (symbolFunction == null)
				symbolFunction = CONST_NULL;
			
			return symbolFunction;
		}
	}

}