/*
 * The contents of this file are subject to the terms of the Common Development and
 * Distribution License (the License). You may not use this file except in compliance with the
 * License.
 *
 * You can obtain a copy of the License at legal/CDDLv1.0.txt. See the License for the
 * specific language governing permission and limitations under the License.
 *
 * When distributing Covered Software, include this CDDL Header Notice in each file and include
 * the License file at legal/CDDLv1.0.txt. If applicable, add the following below the CDDL
 * Header, with the fields enclosed by brackets [] replaced by your own identifying
 * information: "Portions Copyright [year] [name of copyright owner]".
 *
 * Copyright 2010 Sun Microsystems, Inc.
 * Portions copyright 2011-2016 ForgeRock AS.
 */
package org.forgerock.opendj.grizzly;

import java.io.IOException;

import org.forgerock.i18n.LocalizableMessage;
import org.forgerock.i18n.slf4j.LocalizedLogger;
import org.glassfish.grizzly.memory.PooledMemoryManager;
import org.glassfish.grizzly.nio.transport.TCPNIOTransport;
import org.glassfish.grizzly.nio.transport.TCPNIOTransportBuilder;
import org.glassfish.grizzly.strategies.SameThreadIOStrategy;
import org.glassfish.grizzly.strategies.WorkerThreadIOStrategy;
import org.glassfish.grizzly.threadpool.ThreadPoolConfig;

import com.forgerock.opendj.util.ReferenceCountedObject;

/**
 * The default {@link TCPNIOTransport} which all {@code LDAPConnectionFactory}s
 * and {@code LDAPListener}s will use unless otherwise specified in their
 * options.
 */
final class DefaultTCPNIOTransport extends ReferenceCountedObject<TCPNIOTransport> {

    private static final LocalizedLogger logger = LocalizedLogger.getLoggerForThisClass();
    static final DefaultTCPNIOTransport DEFAULT_TRANSPORT = new DefaultTCPNIOTransport();

    private DefaultTCPNIOTransport() {
        // Prevent instantiation.
    }

    @Override
    protected void destroyInstance(final TCPNIOTransport instance) {
        try {
            instance.shutdownNow();
        } catch (final IOException e) {
            // TODO: I18N
            logger.warn(LocalizableMessage.raw("An error occurred while shutting down the Grizzly transport", e));
        }
    }

    @Override
    protected TCPNIOTransport newInstance() {
        final TCPNIOTransportBuilder builder = TCPNIOTransportBuilder.newInstance();

        /*
         * Determine which threading strategy to use, and total number of
         * threads.
         */
        final String useWorkerThreadsStr =
                System.getProperty("org.forgerock.opendj.transport.useWorkerThreads");
        final boolean useWorkerThreadStrategy;
        if (useWorkerThreadsStr != null) {
            useWorkerThreadStrategy = Boolean.parseBoolean(useWorkerThreadsStr);
        } else {
            /*
             * The most best performing strategy to use is the
             * SameThreadIOStrategy, however it can only be used in cases where
             * result listeners will not block.
             */
            useWorkerThreadStrategy = true;
        }

        if (useWorkerThreadStrategy) {
            builder.setIOStrategy(WorkerThreadIOStrategy.getInstance());
        } else {
            builder.setIOStrategy(SameThreadIOStrategy.getInstance());
        }

        // Calculate thread counts.
        final int cpus = Runtime.getRuntime().availableProcessors();

        // Calculate the number of selector threads.
        final String selectorsStr = System.getProperty("org.forgerock.opendj.transport.selectors");
        final int selectorThreadCount;

        if (selectorsStr != null) {
            selectorThreadCount = Integer.parseInt(selectorsStr);
        } else {
            selectorThreadCount =
                    useWorkerThreadStrategy ? Math.max(2, cpus / 4) : Math.max(5, (cpus / 2) - 1);
        }

        builder.setSelectorThreadPoolConfig(ThreadPoolConfig.defaultConfig().setCorePoolSize(
                selectorThreadCount).setMaxPoolSize(selectorThreadCount).setPoolName(
                "OpenDJ LDAP SDK Grizzly selector thread"));

        // Calculate the number of worker threads.
        if (builder.getWorkerThreadPoolConfig() != null) {
            final String workersStr = System.getProperty("org.forgerock.opendj.transport.workers");
            final int workerThreadCount;

            if (workersStr != null) {
                workerThreadCount = Integer.parseInt(workersStr);
            } else {
                workerThreadCount = useWorkerThreadStrategy ? Math.max(5, (cpus * 2)) : 0;
            }

            builder.setWorkerThreadPoolConfig(ThreadPoolConfig.defaultConfig().setCorePoolSize(
                    workerThreadCount).setMaxPoolSize(workerThreadCount).setPoolName(
                    "OpenDJ LDAP SDK Grizzly worker thread"));
        }

        // Parse IO related options.
        final String lingerStr = System.getProperty("org.forgerock.opendj.transport.linger");
        if (lingerStr != null) {
            // Disabled by default.
            builder.setLinger(Integer.parseInt(lingerStr));
        }

        final String tcpNoDelayStr =
                System.getProperty("org.forgerock.opendj.transport.tcpNoDelay");
        if (tcpNoDelayStr != null) {
            // Enabled by default.
            builder.setTcpNoDelay(Boolean.parseBoolean(tcpNoDelayStr));
        }

        final String reuseAddressStr =
                System.getProperty("org.forgerock.opendj.transport.reuseAddress");
        if (reuseAddressStr != null) {
            // Enabled by default.
            builder.setReuseAddress(Boolean.parseBoolean(reuseAddressStr));
        }
        builder.setMemoryManager(new PooledMemoryManager(true));

        final TCPNIOTransport transport = builder.build();

        // FIXME: raise bug in Grizzly. We should not need to do this, but
        // failure to do so causes many deadlocks.
        transport.setSelectorRunnersCount(selectorThreadCount);

        try {
            transport.start();
        } catch (final IOException e) {
            throw new RuntimeException(e);
        }

        return transport;
    }

}