/*******************************************************************************
 * Copyright (c) 2004-2008 Akos Horvath, Gergely Varro and Daniel Varro
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *    Akos Horvath, Gergely Varro - initial API and implementation
 *******************************************************************************/

 package org.eclipse.viatra2.gtasm.patternmatcher.impl.patternmatcher.internal.operation;

import org.eclipse.viatra2.core.IModelElement;
import org.eclipse.viatra2.gtasm.patternmatcher.exceptions.PatternMatcherRuntimeException;
import org.eclipse.viatra2.gtasm.patternmatcher.impl.gtmatcher.exceptions.GTErrorStrings;
import org.eclipse.viatra2.gtasm.patternmatcher.impl.patternmatcher.internal.MatchingFrame;
import org.eclipse.viatra2.gtasm.patternmatcher.impl.patternmatcher.internal.PatternMatcherErrorStrings;
import org.eclipse.viatra2.gtasm.patternmatcher.impl.patternmatcher.internal.searchgraph.SearchGraphEdge;
import org.eclipse.viatra2.gtasmmodel.gtasm.metamodel.asm.core.AnnotatedElement;

import java.util.Iterator;
import java.util.Set;


/**
 * The ExtendOperation is a SearchPlanOperation, where
 * an already bound node is extended towards 
 * an unbound node.
 */
public abstract class ExtendOperation extends SearchPlanOperation {
    protected Integer unbound;
    protected SearchGraphEdge edge;
   
    protected Iterator iterator;
    
    public ExtendOperation(Integer unbound, SearchGraphEdge edge) {
        this.unbound = unbound;
        this.edge = edge;
        this.iterator = null;
    }
    
    public void postprocess(MatchingFrame frame) {
        frame.setValue(unbound, null);
        iterator = null;
    }
    
    public boolean execute(MatchingFrame frame) 
        throws PatternMatcherRuntimeException {
    	Object next = "";
        try {
            if (iterator.hasNext()) {
            	next = iterator.next();
                IModelElement modelElement = (IModelElement) next;
                frame.setValue(unbound, modelElement);
                return true;
            } else {
                return false;
            }
        } catch (ClassCastException e) {
        	String[] context = {edge.getVPMEdgeType().toString(), frame.getPattern().getSearchGraph().getSearchNode(unbound).getName(), next.getClass().getName()};
			throw new PatternMatcherRuntimeException(PatternMatcherErrorStrings.NOT_A_MODELELEMENT_EXTEND
					,context
					,frame.getPattern().getSearchGraph().getSearchNode(unbound).getTraceabilityElement().getRepresentativeEMFElement());
        }
    }
    
    public void calculateSidewaysPassedVariables(Set<Integer> variableSet) {
    	variableSet.remove(unbound);
    }
    
    public AnnotatedElement getErrorfulElement(MatchingFrame frame) {
		return frame.getPattern().getSearchGraph().getSearchNode(unbound).getTraceabilityElement().getRepresentativeEMFElement();
	}
}