package org.maltparser.parser.algorithm.covington;

import org.maltparser.core.exception.MaltChainedException;
import org.maltparser.core.syntaxgraph.DependencyStructure;
import org.maltparser.core.syntaxgraph.edge.Edge;
import org.maltparser.core.syntaxgraph.node.DependencyNode;
import org.maltparser.parser.ParserConfiguration;
import org.maltparser.parser.TransitionSystem;
import org.maltparser.parser.history.GuideUserHistory;
import org.maltparser.parser.history.History;
import org.maltparser.parser.history.action.ComplexDecisionAction;
import org.maltparser.parser.history.action.GuideUserAction;
import org.maltparser.parser.transition.TransitionTable;
/**
 * @author Johan Hall
 *
 */
public class Projective extends TransitionSystem {
	protected static final int SHIFT = 1;
	protected static final int NOARC = 2;
	protected static final int RIGHTARC = 3;
	protected static final int LEFTARC = 4;
	
	
	public Projective() throws MaltChainedException {
		super();
	}
	
	public void apply(GuideUserAction currentAction, ParserConfiguration config) throws MaltChainedException {
		CovingtonConfig covingtonConfig = (CovingtonConfig)config;
		currentAction.getAction(actionContainers);
		
		Edge e = null;
		switch (transActionContainer.getActionCode()) {
		case LEFTARC:
			e = covingtonConfig.getDependencyGraph().addDependencyEdge(covingtonConfig.getRightTarget().getIndex(), covingtonConfig.getLeftTarget().getIndex());
			addEdgeLabels(e);
//			config.setArcParent(covingtonConfig.getRightTarget());
//			config.setArcChild(covingtonConfig.getLeftTarget());
			break;
		case RIGHTARC:
			e = covingtonConfig.getDependencyGraph().addDependencyEdge(covingtonConfig.getLeftTarget().getIndex(), covingtonConfig.getRightTarget().getIndex());
			addEdgeLabels(e);
//			config.setArcParent(covingtonConfig.getLeftTarget());
//			config.setArcChild(covingtonConfig.getRightTarget());
			break;
		default:
//			config.setArcParent(null);
//			config.setArcChild(null);
			break;
		}
		update(covingtonConfig, transActionContainer.getActionCode());	
	}
	
	private void update(CovingtonConfig covingtonConfig, int trans) throws MaltChainedException {
		if (trans == SHIFT || trans == RIGHTARC) {
			covingtonConfig.setRight(covingtonConfig.getRight() + 1);
			covingtonConfig.setLeft(covingtonConfig.getRight() - 1);
		} else {
			int leftstop = covingtonConfig.getLeftstop();
			int left = covingtonConfig.getLeft();
			if (trans == NOARC) {
				DependencyStructure dg = covingtonConfig.getDependencyStructure();
				DependencyNode leftNode = covingtonConfig.getInput().get(covingtonConfig.getLeft());
				if (dg.getTokenNode(leftNode.getIndex()) != null && dg.getTokenNode(leftNode.getIndex()).hasHead()) {
					left = dg.getTokenNode(leftNode.getIndex()).getHead().getIndex();
				} else {
					left = leftstop - 1;
				}
			} else {
				DependencyNode rightNode = covingtonConfig.getRightTarget();
				left--;
				DependencyNode leftNode = null;
				while (left >= leftstop) {
					leftNode = covingtonConfig.getInput().get(left);
					if (rightNode.findComponent().getIndex() != leftNode.findComponent().getIndex()) {
						break;
					}
					left--;
				}
			}
			
			if (left < leftstop) {
				covingtonConfig.setRight(covingtonConfig.getRight() + 1);
				covingtonConfig.setLeft(covingtonConfig.getRight() - 1);
			} else {
				covingtonConfig.setLeft(left);
			}
		}
	}
	
	public GuideUserAction getDeterministicAction(GuideUserHistory history, ParserConfiguration config) throws MaltChainedException {
		return null;
	}
	
	protected void addAvailableTransitionToTable(TransitionTable ttable) throws MaltChainedException {
		ttable.addTransition(SHIFT, "SH", false, null);
		ttable.addTransition(NOARC, "NA", false, null);
		ttable.addTransition(RIGHTARC, "RA", true, null);
		ttable.addTransition(LEFTARC, "LA", true, null);
	}
	
	protected void initWithDefaultTransitions(GuideUserHistory history) throws MaltChainedException {
		GuideUserAction currentAction = new ComplexDecisionAction((History)history);
		
		transActionContainer.setAction(SHIFT);
		transActionContainer.setAction(NOARC);
		for (int i = 0; i < arcLabelActionContainers.length; i++) {
			arcLabelActionContainers[i].setAction(-1);
		}
		currentAction.addAction(actionContainers);
	}
	
	public String getName() {
		return "covnonproj";
	}
	
	public boolean permissible(GuideUserAction currentAction, ParserConfiguration config) throws MaltChainedException {
		CovingtonConfig covingtonConfig = (CovingtonConfig)config;
		DependencyNode leftTarget = covingtonConfig.getLeftTarget();
		DependencyNode rightTarget = covingtonConfig.getRightTarget();
		DependencyStructure dg = covingtonConfig.getDependencyGraph();
		currentAction.getAction(actionContainers);
		int trans = transActionContainer.getActionCode();
		
		if (trans == SHIFT && covingtonConfig.isAllowShift() == false) {
			return false;
		}
		if ((trans == LEFTARC || trans == RIGHTARC) && !isActionContainersLabeled()) {
			return false;
		}
		if (trans == LEFTARC && leftTarget.isRoot()) { 
			return false;
		}
		if (trans == LEFTARC && dg.hasLabeledDependency(leftTarget.getIndex())) { 
			return false;
		}
		if (trans == RIGHTARC && dg.hasLabeledDependency(rightTarget.getIndex())) { 
			return false;
		}
		return true;
	}
	
	public GuideUserAction defaultAction(GuideUserHistory history, ParserConfiguration configuration) throws MaltChainedException {
		return updateActionContainers(history, Projective.NOARC, null);
	}
}