package app.bbs;

import java.nio.ByteBuffer;

import alice.jungle.operations.NetworkTreeOperationLog;
import alice.jungle.transaction.JungleUpdater;
import jp.ac.u_ryukyu.ie.cr.shoshi.jungle.DefaultJungle;
import jp.ac.u_ryukyu.ie.cr.shoshi.jungle.Jungle;
import jp.ac.u_ryukyu.ie.cr.shoshi.jungle.JungleTree;
import jp.ac.u_ryukyu.ie.cr.shoshi.jungle.JungleTreeEditor;
import jp.ac.u_ryukyu.ie.cr.shoshi.jungle.core.Node;
import jp.ac.u_ryukyu.ie.cr.shoshi.jungle.store.impl.DefaultTreeEditor;
import jp.ac.u_ryukyu.ie.cr.shoshi.jungle.traverser.DefaultTraverser;
import jp.ac.u_ryukyu.ie.cr.shoshi.jungle.util.Either;
import jp.ac.u_ryukyu.ie.cr.shoshi.jungle.util.Error;

public class BulletinBoardJungleManager {
	private static BulletinBoardJungleManager instance = new BulletinBoardJungleManager();
	private Jungle jungle;

	private BulletinBoardJungleManager() {
		jungle = new DefaultJungle(null,"default",new DefaultTreeEditor(new DefaultTraverser()));
	}
	
	public static BulletinBoardJungleManager getInstantce() {
		return instance;
	}
	
	public static void setJungle(Jungle _j) {
		instance.jungle = _j;
	}
	
	public static Jungle getJungle() {
		return instance.jungle;
	}
	
	public static JungleTree createNewTree(String name) {
		return instance.jungle.createNewTree(name);	
	}

	public static Either<Error, JungleTreeEditor> update(NetworkTreeOperationLog netLog) {
		String treeName = netLog.getTreeName();
		Jungle jungle = BulletinBoardJungleManager.getJungle(); 
		if (jungle.getTreeByName(treeName) == null) {
			if(null == jungle.createNewTree(treeName)){
				throw new IllegalStateException();
			}
		}
		Either<Error, JungleTreeEditor> either = null;
		do {
			JungleTree tree = jungle.getTreeByName(treeName);
			JungleTreeEditor editor = tree.getLocalTreeEditor();

			/* 
			 * Merge. 
			 */
			int pos = calculatePosition(tree.getRootNode(), netLog.getTimeStamp());
			either = JungleUpdater.edit(editor, netLog, pos);
			if(either.isA()) {
				throw new IllegalStateException();
			}

			editor = either.b();
			either = editor.success();
		}while(either.isA());
		return either;
	}
	
	private static int calculatePosition(Node node, long newNodeTimeStamp) {
		int count = 0;
		long childTimeStamp = 0;
		for(Node n : node.getChildren()) {
			ByteBuffer timestamp = n.getAttributes().get("timestamp");
			if(timestamp == null) {
				return count;
			}
			childTimeStamp = timestamp.getLong(0);
			if (newNodeTimeStamp < childTimeStamp) {
				break;
			}
			count++;
		}
		return count;
	}
}