package jp.ac.u_ryukyu.ie.cr.jungle.transaction.manager;

import jp.ac.u_ryukyu.ie.cr.jungle.data.list.List;
import jp.ac.u_ryukyu.ie.cr.jungle.persistent.ChangeList;
import jp.ac.u_ryukyu.ie.cr.jungle.persistent.ChangeListWriter;
import jp.ac.u_ryukyu.ie.cr.jungle.query.traverser.InterfaceTraverser;
import jp.ac.u_ryukyu.ie.cr.jungle.query.traverser.RedBlackTreeInterfaceTraverser;
import jp.ac.u_ryukyu.ie.cr.jungle.store.TreeContext;
import jp.ac.u_ryukyu.ie.cr.jungle.store.logger.TreeOperationLog;
import jp.ac.u_ryukyu.ie.cr.jungle.store.operations.TreeOperation;
import jp.ac.u_ryukyu.ie.cr.jungle.transaction.context.DefaultTreeContext;
import jp.ac.u_ryukyu.ie.cr.jungle.transaction.node.TreeNode;
import jp.ac.u_ryukyu.ie.cr.jungle.util.DefaultEither;
import jp.ac.u_ryukyu.ie.cr.jungle.util.Either;
import jp.ac.u_ryukyu.ie.cr.jungle.util.Error.DefaultError;
import jp.ac.u_ryukyu.ie.cr.jungle.util.Error.Error;

import java.util.Iterator;
import java.util.concurrent.atomic.AtomicReference;

public class RedBlackTreeTransactionManager implements TransactionManager {
    private final AtomicReference<TreeContext> repository;
    private final TreeContext tip;
    private final ChangeListWriter writer;
    private final String uuid;

    public RedBlackTreeTransactionManager(ChangeListWriter _writer, TreeContext _tip, AtomicReference<TreeContext> _repository, String _uuid) {
        repository = _repository;
        tip = _tip;
        writer = _writer;
        uuid = _uuid;
    }


    @Override
    public Either<Error, TransactionManager> commit(TreeNode newRoot, final TreeOperationLog _log, List<TreeNode> editNodeList) {
        long currentRevision = tip.revision();
        long nextRevision = currentRevision + 1;

        final String _treeName = tip.getTreeName();
        ChangeList list = new ChangeList() {
            @Override
            public Iterator<TreeOperation> iterator() {
                return _log.iterator();
            }

            @Override
            public String getTreeName() {
                return _treeName;
            }

            @Override
            public TreeOperationLog getLog() {
                return _log;
            }

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

        };

        InterfaceTraverser traverser = new RedBlackTreeInterfaceTraverser(newRoot);
        TreeContext newTreeContext = new DefaultTreeContext(newRoot, tip, list, uuid, _treeName, nextRevision, traverser);

        if (repository.compareAndSet(newTreeContext.prev(), newTreeContext)) {
            TransactionManager txManager = new RedBlackTreeTransactionManager(writer, newTreeContext, repository, uuid);
            return DefaultEither.newB(txManager);
        }

        return DefaultEither.newA((Error) new DefaultError());
    }

    @Override
    public Either<Error, TransactionManager> flashCommit(TreeNode _newRoot, TreeOperationLog _log) {
        return null;//commit(_newRoot, _log);
    }

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

    @Override
    public long getRevision() {
        return tip.revision();
    }
}