package org.maltparser.parser.algorithm.covington;

import org.maltparser.core.exception.MaltChainedException;
import org.maltparser.core.syntaxgraph.DependencyStructure;
import org.maltparser.core.syntaxgraph.node.DependencyNode;
import org.maltparser.parser.DependencyParserConfig;
import org.maltparser.parser.Oracle;
import org.maltparser.parser.ParserConfiguration;
import org.maltparser.parser.history.GuideUserHistory;
import org.maltparser.parser.history.action.GuideUserAction;

/**
 * @author Johan Hall
 *
 */
public class CovingtonOracle extends Oracle {

    public CovingtonOracle(DependencyParserConfig manager, GuideUserHistory history) throws MaltChainedException {
        super(manager, history);
        setGuideName("NonProjective");
    }

    public GuideUserAction predict(DependencyStructure gold, ParserConfiguration config) throws MaltChainedException {
        CovingtonConfig covingtonConfig = (CovingtonConfig) config;
        DependencyNode leftTarget = covingtonConfig.getLeftTarget();
        int leftTargetIndex = leftTarget.getIndex();
        int rightTargetIndex = covingtonConfig.getRightTarget().getIndex();

        if (!leftTarget.isRoot() && gold.getTokenNode(leftTargetIndex).getHead().getIndex() == rightTargetIndex) {
            return updateActionContainers(NonProjective.LEFTARC, gold.getTokenNode(leftTargetIndex).getHeadEdge().getLabelSet());
        } else if (gold.getTokenNode(rightTargetIndex).getHead().getIndex() == leftTargetIndex) {
            return updateActionContainers(NonProjective.RIGHTARC, gold.getTokenNode(rightTargetIndex).getHeadEdge().getLabelSet());
        } else if (covingtonConfig.isAllowShift() == true && (!(gold.getTokenNode(rightTargetIndex).hasLeftDependent()
                && gold.getTokenNode(rightTargetIndex).getLeftmostDependent().getIndex() < leftTargetIndex)
                && !(gold.getTokenNode(rightTargetIndex).getHead().getIndex() < leftTargetIndex
                && (!gold.getTokenNode(rightTargetIndex).getHead().isRoot() || covingtonConfig.getLeftstop() == 0)))) {
            return updateActionContainers(NonProjective.SHIFT, null);
        } else {
            return updateActionContainers(NonProjective.NOARC, null);
        }
    }

    public void finalizeSentence(DependencyStructure dependencyGraph) throws MaltChainedException {
    }

    public void terminate() throws MaltChainedException {
    }
}