/**
 * DataCleaner (community edition)
 * Copyright (C) 2014 Neopost - Customer Information Management
 *
 * This copyrighted material is made available to anyone wishing to use, modify,
 * copy, or redistribute it subject to the terms and conditions of the GNU
 * Lesser General Public License, as published by the Free Software Foundation.
 *
 * This program 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 distribution; if not, write to:
 * Free Software Foundation, Inc.
 * 51 Franklin Street, Fifth Floor
 * Boston, MA  02110-1301  USA
 */
package org.datacleaner.bootstrap;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

class DCExitActionListener implements ExitActionListener {

    private static final Logger logger = LoggerFactory.getLogger(DCExitActionListener.class);

    public static void printThreadInformation(final ThreadGroup threadGroup, final String prefix) {
        logger.warn("Thread group: " + threadGroup);

        final ThreadGroup[] groups = new ThreadGroup[threadGroup.activeGroupCount() + 2];
        final int groupCount = threadGroup.enumerate(groups);
        for (int i = 0; i < groupCount; i++) {
            final ThreadGroup group = groups[i];
            printThreadInformation(group, prefix + "  ");
        }

        final Thread[] threads = new Thread[threadGroup.activeCount() + 4];
        final int threadCount = threadGroup.enumerate(threads);

        for (int i = 0; i < threadCount; i++) {
            final Thread thread = threads[i];
            if (thread != null) {
                final boolean alive = thread.isAlive();
                final boolean daemon = thread.isDaemon();
                logger.warn(
                        prefix + "thread #" + (i + 1) + " (" + (alive ? "alive" : "dead") + (daemon ? ",daemon" : "")
                                + ")" + ": " + thread);
                if (alive && !daemon) {
                    final StackTraceElement[] stackTrace = thread.getStackTrace();
                    for (int j = stackTrace.length - 1; j >= 0; j--) {
                        logger.warn(prefix + " | stack " + (j + 1) + ": " + stackTrace[j]);
                    }
                }
            }
        }
    }

    @Override
    public void exit(final int statusCode) {
        final Thread thread = new Thread() {
            @Override
            public void run() {
                try {
                    // sleep for 5 seconds, to give the non-daemon threads a
                    // chance to shut down the applications properly
                    Thread.sleep(5000);
                } catch (final InterruptedException e) {
                    logger.info("Interrupted", e);
                }

                if (logger.isWarnEnabled()) {
                    logger.warn("Some threads are still running:");

                    ThreadGroup topLevelThreadGroup = null;
                    {
                        ThreadGroup threadGroup = Thread.currentThread().getThreadGroup();
                        while (threadGroup != null) {
                            topLevelThreadGroup = threadGroup;
                            threadGroup = threadGroup.getParent();
                        }
                    }
                    printThreadInformation(topLevelThreadGroup, "");

                    logger.warn("Invoking system.exit({})", statusCode);
                }

                System.exit(statusCode);
            }
        };
        thread.setDaemon(true);

        logger.info("Scheduling shutdown thread");
        thread.start();
    }
}