package org.simantics.browsing.ui.graph.impl;

import java.util.Collection;

import org.simantics.browsing.ui.BuiltinKeys.ViewpointKey;
import org.simantics.browsing.ui.NodeContext;
import org.simantics.browsing.ui.PrimitiveQueryUpdater;
import org.simantics.browsing.ui.model.browsecontexts.BrowseContext;
import org.simantics.db.ReadGraph;
import org.simantics.db.common.request.UniqueRead;
import org.simantics.db.exception.DatabaseException;

public class EvaluatorViewpoint extends LazyViewpoint {

	final BrowseContext browseContext;
	final boolean useNodeBrowseContexts;
	final boolean useNodeActionContexts;
	
    public EvaluatorViewpoint(PrimitiveQueryUpdater updater, NodeContext context, ViewpointKey key,
    		BrowseContext browseContext, boolean useNodeBrowseContexts, boolean useNodeActionContexts) {
		super(updater, context, key);
		this.browseContext = browseContext;
		this.useNodeActionContexts = useNodeActionContexts;
		this.useNodeBrowseContexts = useNodeBrowseContexts;
	}

	@Override
    public Boolean hasChildren(ReadGraph graph) throws DatabaseException {
        return BrowseContext.get(graph,context,browseContext,useNodeBrowseContexts).hasChildren(graph, context);
    }

    @Override
    public NodeContext[] children(ReadGraph graph) throws DatabaseException {
    	boolean oldSynchronous = graph.setSynchronous(false); 
    	try {
    		// This intermediate query is a work-around for a listening
    		// bug where old dependencies are not correctly pruned for listened entries
    		return graph.syncRequest(new UniqueRead<NodeContext[]>() {

				@Override
				public NodeContext[] perform(ReadGraph graph) throws DatabaseException {
		    		BrowseContext bc = BrowseContext.get(graph,context,browseContext,useNodeBrowseContexts);
		    		Collection<NodeContext> children = bc.getChildren(graph, context);
		    		children = BrowseContext.augment(graph, bc, children, useNodeActionContexts);
		    		return children.toArray(new NodeContext[children.size()]);
				}
    			
    		});
    	} finally {
    		graph.setSynchronous(oldSynchronous);
    	}
    }
    
    public String toString() {
    	return "EvaluatorViewpoint[" + browseContext + "] " + context;
    }
    
}