/*
 * Copyright 2015-2020 Real Logic Limited.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * https://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package uk.co.real_logic.artio.server;

import io.aeron.archive.Archive;
import io.aeron.archive.ArchiveThreadingMode;
import io.aeron.archive.ArchivingMediaDriver;
import io.aeron.driver.MediaDriver.Context;
import org.agrona.IoUtil;
import org.agrona.concurrent.IdleStrategy;
import org.agrona.concurrent.SigInt;
import uk.co.real_logic.artio.CommonConfiguration;
import uk.co.real_logic.artio.SampleUtil;
import uk.co.real_logic.artio.engine.EngineConfiguration;
import uk.co.real_logic.artio.engine.FixEngine;
import uk.co.real_logic.artio.library.AcquiringSessionExistsHandler;
import uk.co.real_logic.artio.library.FixLibrary;
import uk.co.real_logic.artio.library.LibraryConfiguration;
import uk.co.real_logic.artio.library.SessionHandler;
import uk.co.real_logic.artio.session.Session;
import uk.co.real_logic.artio.validation.AuthenticationStrategy;
import uk.co.real_logic.artio.validation.MessageValidationStrategy;

import java.io.File;
import java.util.Collections;
import java.util.concurrent.atomic.AtomicBoolean;

import static io.aeron.driver.ThreadingMode.SHARED;
import static java.util.Collections.singletonList;
import static uk.co.real_logic.artio.messages.SessionState.DISCONNECTED;

public final class SampleServer
{
    public static final String ACCEPTOR_COMP_ID = "acceptor";
    public static final String INITIATOR_COMP_ID = "initiator";

    private static Session session;

    public static void main(final String[] args)
    {
        final MessageValidationStrategy validationStrategy = MessageValidationStrategy.targetCompId(ACCEPTOR_COMP_ID)
            .and(MessageValidationStrategy.senderCompId(Collections.singletonList(INITIATOR_COMP_ID)));

        final AuthenticationStrategy authenticationStrategy = AuthenticationStrategy.of(validationStrategy);

        // Static configuration lasts the duration of a FIX-Gateway instance
        final String aeronChannel = "aeron:udp?endpoint=localhost:10000";
        final EngineConfiguration configuration = new EngineConfiguration()
            .bindTo("localhost", 9999)
            .libraryAeronChannel(aeronChannel);
        configuration.authenticationStrategy(authenticationStrategy);

        cleanupOldLogFileDir(configuration);

        final Context context = new Context()
            .threadingMode(SHARED)
            .dirDeleteOnStart(true);

        final Archive.Context archiveContext = new Archive.Context()
            .threadingMode(ArchiveThreadingMode.SHARED)
            .deleteArchiveOnStart(true);

        try (ArchivingMediaDriver driver = ArchivingMediaDriver.launch(context, archiveContext);
            FixEngine gateway = FixEngine.launch(configuration))
        {
            final LibraryConfiguration libraryConfiguration = new LibraryConfiguration();

            // You register the new session handler - which is your application hook
            // that receives messages for new sessions
            libraryConfiguration
                .sessionAcquireHandler((session, acquiredInfo) -> onConnect(session))
                .sessionExistsHandler(new AcquiringSessionExistsHandler())
                .libraryAeronChannels(singletonList(aeronChannel));

            final IdleStrategy idleStrategy = CommonConfiguration.backoffIdleStrategy();

            try (FixLibrary library = SampleUtil.blockingConnect(libraryConfiguration))
            {
                final AtomicBoolean running = new AtomicBoolean(true);
                SigInt.register(() -> running.set(false));

                while (running.get())
                {
                    idleStrategy.idle(library.poll(1));

                    if (session != null && session.state() == DISCONNECTED)
                    {
                        break;
                    }
                }
            }
        }

        System.exit(0);
    }

    public static void cleanupOldLogFileDir(final EngineConfiguration configuration)
    {
        IoUtil.delete(new File(configuration.logFileDir()), true);
    }

    private static SessionHandler onConnect(final Session session)
    {
        SampleServer.session = session;

        // Simple server just handles a single connection on a single thread
        // You choose how to manage threads for your application.

        return new SampleSessionHandler(session);
    }
}