package alice.jungle.persistent;

import java.util.Iterator;

import jp.ac.u_ryukyu.ie.cr.shoshi.jungle.core.Node;
import jp.ac.u_ryukyu.ie.cr.shoshi.jungle.persistent.ChangeListWriter;
import jp.ac.u_ryukyu.ie.cr.shoshi.jungle.persistent.Result;
import jp.ac.u_ryukyu.ie.cr.shoshi.jungle.store.ChangeSet;
import jp.ac.u_ryukyu.ie.cr.shoshi.jungle.store.impl.TreeNode;
import jp.ac.u_ryukyu.ie.cr.shoshi.jungle.store.impl.logger.TreeOperationLog;
import jp.ac.u_ryukyu.ie.cr.shoshi.jungle.transaction.AtomicReservableReference;
import jp.ac.u_ryukyu.ie.cr.shoshi.jungle.transaction.DefaultTreeContext;
import jp.ac.u_ryukyu.ie.cr.shoshi.jungle.transaction.TransactionManager;
import jp.ac.u_ryukyu.ie.cr.shoshi.jungle.transaction.TreeContext;
import jp.ac.u_ryukyu.ie.cr.shoshi.jungle.transaction.AtomicReservableReference.Reservation;
import jp.ac.u_ryukyu.ie.cr.shoshi.jungle.util.DefaultEither;
import jp.ac.u_ryukyu.ie.cr.shoshi.jungle.util.DefaultError;
import jp.ac.u_ryukyu.ie.cr.shoshi.jungle.util.Either;
import jp.ac.u_ryukyu.ie.cr.shoshi.jungle.util.Error;

public class PersistentTransactionManager<T extends TreeNode<T>> implements TransactionManager<T> { 
	private final AtomicReservableReference<TreeContext<T>> repository;
	private final TreeContext<T> tip;
	private final ChangeListWriter writer;
	private final String uuid;		
	private final String treeName;	

	public PersistentTransactionManager(String _treeName, ChangeListWriter _writer,TreeContext<T> _tip,
			AtomicReservableReference<TreeContext<T>> _repository,String _uuid)
	{
		repository = _repository;
		tip = _tip;
		writer = _writer;
		uuid = _uuid;
		treeName = _treeName;
	}
	
	@Override
	public Either<Error, TransactionManager<T>> commit(T _newRoot,final TreeOperationLog _log) {
		ChangeSet cs = tip.getChangeSet();
		long currentRevision = cs.revision();
		long nextRevision = currentRevision + 1;
		
		PersistentChangeList list = new PersistentChangeList(uuid, treeName, _log);
		Node root = _newRoot.getAsNode();
		PersistentChangeSet newCs = new PersistentChangeSet(root, cs, list, uuid, treeName, nextRevision);
		DefaultTreeContext<T> newContext = new DefaultTreeContext<T>(_newRoot,newCs);
		
		@SuppressWarnings("rawtypes")
		Reservation reservation = repository.makeReservation(tip, newContext);
		if(reservation == null) {
			return DefaultEither.newA((Error)new DefaultError());
		}
		Result r = writer.write(list);
		if(r != Result.SUCCESS) {
			return DefaultEither.newA((Error)new DefaultError());
		}
		reservation.confirm();
		TransactionManager<T> txManager = new PersistentTransactionManager<T>(treeName, writer, newContext, repository, uuid);
		return DefaultEither.newB(txManager);
	}

	@Override
	public long getRevision() 
	{
		ChangeSet cs = tip.getChangeSet();
		return cs.revision();
	}

	@Override
	public String getUUID() {
		return uuid;
	}
	
	
	
}