/*
 * JBoss, a division of Red Hat
 * Copyright 2012, Red Hat Middleware, LLC, and individual
 * contributors as indicated by the @authors tag. See the
 * copyright.txt in the distribution for a full listing of
 * individual contributors.
 *
 * This is free software; you can redistribute it and/or modify it
 * under the terms of the GNU Lesser General Public License as
 * published by the Free Software Foundation; either version 2.1 of
 * the License, or (at your option) any later version.
 *
 * This software is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this software; if not, write to the Free
 * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
 * 02110-1301 USA, or see the FSF site: http://www.fsf.org.
 */

package org.gatein.common.transaction;

import java.util.LinkedList;
import java.util.List;

import javax.naming.InitialContext;
import javax.naming.NamingException;
import javax.transaction.Status;
import javax.transaction.UserTransaction;

import org.exoplatform.services.transaction.TransactionService;
import org.exoplatform.services.log.ExoLogger;
import org.exoplatform.services.log.Log;

/**
 * Base implementation of {@link JTAUserTransactionLifecycleService} .
 *
 * @author <a href="mailto:mposolda@redhat.com">Marek Posolda</a>
 */
public class JTAUserTransactionLifecycleServiceImpl implements JTAUserTransactionLifecycleService {
  private static final Log                          log       = ExoLogger.getLogger(JTAUserTransactionLifecycleServiceImpl.class);

    private UserTransaction userTransaction;

    private TransactionService transactionService;

    // For now, we have one listener instance for all transactions
    private List<JTAUserTransactionLifecycleListener> listeners = new LinkedList<JTAUserTransactionLifecycleListener>();

    public JTAUserTransactionLifecycleServiceImpl(TransactionService transactionService) {
        this.transactionService = transactionService;
    }

    /**
     * {@inheritDoc}
     */
    public void beginJTATransaction() {
        UserTransaction tx = getUserTransaction();

        try {
            if (tx.getStatus() == Status.STATUS_NO_TRANSACTION) {
                executeListenersBeforeBegin();
                tx.begin();
                executeListenersAfterBegin();
            } else {
                log.warn("UserTransaction not started as it's in state " + tx.getStatus());
            }
        } catch (Exception e) {
            throw new RuntimeException(e);
        }
    }

    /**
     * {@inheritDoc}
     */
    public void finishJTATransaction() {
        UserTransaction tx = getUserTransaction();

        try {
            int txStatus = tx.getStatus();
            if (txStatus == Status.STATUS_NO_TRANSACTION) {
                log.warn("UserTransaction can't be finished as it wasn't started");
            } else if (txStatus == Status.STATUS_MARKED_ROLLBACK || txStatus == Status.STATUS_ROLLEDBACK
                    || txStatus == Status.STATUS_ROLLING_BACK) {
                log.warn("Going to rollback UserTransaction as it's status is " + txStatus);
                tx.rollback();
            } else {
                tx.commit();
            }
        } catch (Exception se) {
            throw new RuntimeException(se);
        }
    }

    /**
     * Obtain {@link UserTransaction} via JNDI call or via {@link TransactionService} if that fails
     *
     * @return transaction
     */
    public UserTransaction getUserTransaction() {
        // It's fine to reuse same instance of UserTransaction as UserTransaction is singleton in JBoss and most other AS.
        // And new InitialContext().lookup("java:comp/UserTransaction") is quite expensive operation
        if (userTransaction == null) {
            synchronized (this) {
                if (userTransaction == null) {
                    try {
                        userTransaction = (UserTransaction) new InitialContext().lookup("java:comp/UserTransaction");
                    } catch (NamingException ne) {
                        log.debug("UserTransaction not found via JNDI. Trying TransactionService");
                        userTransaction = transactionService.getUserTransaction();
                    }
                }
            }
        }
        return userTransaction;
    }

    /**
     * {@inheritDoc}
     */
    public void registerListener(JTAUserTransactionLifecycleListener listener) {
        log.info("Registered listener " + listener);
        listeners.add(listener);
    }

    protected void executeListenersBeforeBegin() {
        for (JTAUserTransactionLifecycleListener listener : listeners) {
            if (log.isTraceEnabled()) {
                log.trace("Execute listener " + listener + " before begin of JTA transaction");
            }
            listener.beforeBegin();
        }
    }

    protected void executeListenersAfterBegin() {
        for (JTAUserTransactionLifecycleListener listener : listeners) {
            if (log.isTraceEnabled()) {
                log.trace("Execute listener " + listener + " after begin of JTA transaction");
            }
            listener.afterBegin();
        }
    }
}
