package jp.ac.u_ryukyu.ie.cr.shoshi.jungle.traverser;

import jp.ac.u_ryukyu.ie.cr.shoshi.jungle.store.NodePath;
import jp.ac.u_ryukyu.ie.cr.shoshi.jungle.util.Pair;

public class DefaultEvaluator<T extends TraversableNode<T>> implements Evaluator<T>
{
	private final NodePath path;
	
	public DefaultEvaluator(NodePath _path)
	{
		path = _path;
	}
	
	@Override
	public Evaluation<T> evaluate(T _current,int _pos)
	{
		Pair<Integer,NodePath> pop = path.pop();
		if(pop == null){
			return new DefaultEvaluation<T>(Result.BREAK,null);
		}
		
		DefaultEvaluator<T> nextEvaluator = new DefaultEvaluator<T>(pop.right());
		int head = pop.left();
		
		Result result = Result.CONTINUE;
		if(head == _pos){
			result = Result.ACCEPT;
		}
		
		return new DefaultEvaluation<T>(result,nextEvaluator);
	}
}