/*
 * 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.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 ServerTCPNIOTransport extends ReferenceCountedObject<TCPNIOTransport> {

    private static final LocalizedLogger logger = LocalizedLogger.getLoggerForThisClass();
    static final ServerTCPNIOTransport SERVER_TRANSPORT = new ServerTCPNIOTransport();
    private static final long MB = 1024 * 1024;

    private ServerTCPNIOTransport() {
        // 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();

        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 = Math.max(5, (cpus / 2) - 1);
        }

        builder.setSelectorThreadPoolConfig(
                ThreadPoolConfig.defaultConfig()
                                .setCorePoolSize(selectorThreadCount)
                                .setMaxPoolSize(selectorThreadCount)
                                .setPoolName("OpenDJ LDAP SDK Grizzly selector 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));
        }
        float heapPercent;
        if (Runtime.getRuntime().maxMemory() < 1024 * MB) {
            // Low heap
            heapPercent = 0.01f;
        } else {
            // Compute a percentage to try to reach roughly 64Mb (big enough (tm))
            heapPercent = 64f * MB / Runtime.getRuntime().maxMemory();
        }
        // Force usage of PooledMemoryManager which allows to use grizzly's buffers across threads.
        builder.setMemoryManager(new PooledMemoryManager(
                1024,  // Initial buffer size
                3,     // Number of pools (with growing factor below this give us pools of 1K, 4K, 16k buffers)
                4,     // Growing factor to apply on the size of the buffer polled by the next pool
                selectorThreadCount,    // Number of pool slices that every pool will stripe allocation requests across
                heapPercent, // The percentage of the heap that this manager will use when populating the pools (5%)
                1f,    // The percentage of buffers to be pre-allocated during MemoryManager initialization (100%)
                true   // true to use direct buffers or false to use heap buffers
        ));

        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;
    }

}