package elkDemo5;

import org.eclipse.elk.alg.graphviz.layouter.DotOptions;
import org.eclipse.elk.alg.graphviz.layouter.GraphvizMetaDataProvider;

import org.eclipse.elk.core.RecursiveGraphLayoutEngine;
import org.eclipse.elk.core.data.LayoutMetaDataService;
import org.eclipse.elk.core.options.CoreOptions;
import org.eclipse.elk.core.options.EdgeLabelPlacement;

import org.eclipse.elk.core.util.BasicProgressMonitor;
import org.eclipse.elk.core.util.IElkProgressMonitor;

import org.eclipse.elk.graph.ElkEdge;
import org.eclipse.elk.graph.ElkLabel;
import org.eclipse.elk.graph.ElkNode;
import org.eclipse.elk.graph.util.ElkGraphUtil;

import com.google.common.collect.Iterators;
import com.google.common.collect.UnmodifiableIterator;

public class Main {

	public static void main(String[] args) {
		ElkNode top = ElkGraphUtil.createGraph();
        top.setProperty(CoreOptions.ALGORITHM, DotOptions.ALGORITHM_ID);
		ElkLabel L1 = ElkGraphUtil.createLabel("Top",top);
		setPropertyValues(L1);
        
        ElkNode A = ElkGraphUtil.createNode(top);
		ElkLabel L2 = ElkGraphUtil.createLabel("A",A);
		setPropertyValues(L2);
		
        ElkNode B = ElkGraphUtil.createNode(top);
		ElkLabel L3 = ElkGraphUtil.createLabel("B",B);	
		setPropertyValues(L3);
		
        ElkEdge E1 = ElkGraphUtil.createSimpleEdge(A, B);
        ElkLabel L4 = ElkGraphUtil.createLabel("A=>B",E1);
		setPropertyValues(L4);
		
		getAllElkNodes(top).forEachRemaining(node -> {      
			if (!node.getChildren().isEmpty()) {
	           node.setProperty(CoreOptions.ALGORITHM, DotOptions.ALGORITHM_ID);
			}
		});
      
	    IElkProgressMonitor progressMonitor = new BasicProgressMonitor();
	    		
	    LayoutMetaDataService service = LayoutMetaDataService.getInstance();

	    service.registerLayoutMetaDataProviders(new GraphvizMetaDataProvider());
	    
	    RecursiveGraphLayoutEngine layoutEngine = new RecursiveGraphLayoutEngine();
	    
	    layoutEngine.layout(top, progressMonitor);
	}
	
	private static UnmodifiableIterator<ElkNode> getAllElkNodes(final ElkNode parentNode) {
	    return Iterators.filter(parentNode.eAllContents(), ElkNode.class);
	}
	private static void setPropertyValues(ElkLabel labelIn) {
		labelIn.setProperty(CoreOptions.FONT_SIZE,10);
		labelIn.setProperty(CoreOptions.FONT_NAME,"Helvetica");
		labelIn.setProperty(CoreOptions.EDGE_LABELS_PLACEMENT,EdgeLabelPlacement.HEAD);
	}
}