package org.eclipse.emf.henshin.variability.util;

import java.util.HashSet;
import java.util.List;
import java.util.Set;
import java.util.stream.Collectors;
import java.util.stream.Stream;

import org.eclipse.emf.henshin.model.Attribute;
import org.eclipse.emf.henshin.model.Edge;
import org.eclipse.emf.henshin.model.GraphElement;
import org.eclipse.emf.henshin.model.Node;
import org.eclipse.emf.henshin.model.Rule;
import org.eclipse.emf.henshin.model.Unit;
import org.eclipse.emf.henshin.variability.matcher.FeatureExpression;
import org.eclipse.emf.henshin.variability.wrapper.VariabilityConstants;
import org.eclipse.emf.henshin.variability.wrapper.VariabilityFactory;
import org.eclipse.emf.henshin.variability.wrapper.VariabilityRule;

import aima.core.logic.propositional.parsing.ast.PropositionSymbol;
import aima.core.logic.propositional.visitors.SymbolCollector;

/**
 * 
 * @author Daniel Strüber
 * @author Sven Peldszus
 *
 */
public class RuleUtil {

	public static void removeElementsFromRule(Rule rule, List<GraphElement> elementsToRemove) {
		Set<Node> nodes2delete = new HashSet<Node>();
		Set<Edge> edges2delete = new HashSet<Edge>();
		Set<Attribute> attribs2delete = new HashSet<Attribute>();

		for (GraphElement o : elementsToRemove) {
			if (o instanceof Node) {
				Node n = (Node) o;
				nodes2delete.add(n);
				edges2delete.addAll(n.getIncoming());
				edges2delete.addAll(n.getOutgoing());
			} else if (o instanceof Edge)
				edges2delete.add((Edge) o);
			else if (o instanceof Attribute)
				attribs2delete.add((Attribute) o);
		}

		for (Attribute a : attribs2delete)
			rule.removeAttribute(a, true);
		for (Edge e : edges2delete)
			rule.removeEdge(e, true);
		for (Node n : nodes2delete)
			rule.removeNode(n, true);
	}

	public static boolean isVarRule(Unit unit) {
		if (unit instanceof Rule) {
			if (VariabilityFactory.INSTANCE.createVariabilityRule((Rule) unit).getFeatureConstraint() != null) {
				return true;
			}
		}
		return false;
	}

	public static boolean checkRule(Rule rule) {
		if (!isVarRule(rule)) {
			return true;
		}
		VariabilityRule varRule = VariabilityFactory.INSTANCE.createVariabilityRule(rule);
		List<String> features = varRule.getFeatures();

		Stream<PropositionSymbol> fm = SymbolCollector
				.getSymbolsFrom(FeatureExpression.getExpr(varRule.getFeatureConstraint())).parallelStream();
		Stream<PropositionSymbol> symbols = varRule.getAnnotations().parallelStream()
				.filter(annot -> VariabilityConstants.PRESENCE_CONDITION.equals(annot.getKey()))
				.flatMap(annot -> SymbolCollector.getSymbolsFrom(FeatureExpression.getExpr(annot.getValue()))
						.parallelStream());
		List<String> symbolNames = Stream.concat(fm, symbols).map(symbol -> symbol.getSymbol()).distinct()
				.collect(Collectors.toList());

		return features.containsAll(symbolNames);
	}
}