/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You 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
 *
 *     http://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 org.apache.dubbo.remoting.transport.quic;

import org.apache.dubbo.common.URL;
import org.apache.dubbo.common.logger.Logger;
import org.apache.dubbo.common.logger.LoggerFactory;
import org.apache.dubbo.common.utils.ExecutorUtil;
import org.apache.dubbo.common.utils.NetUtils;
import org.apache.dubbo.remoting.Channel;
import org.apache.dubbo.remoting.ChannelHandler;
import org.apache.dubbo.remoting.RemotingException;
import org.apache.dubbo.remoting.RemotingServer;
import org.apache.dubbo.remoting.transport.AbstractServer;
import org.apache.dubbo.remoting.transport.dispatcher.ChannelHandlers;
import org.apache.dubbo.remoting.utils.UrlUtils;

import io.netty.bootstrap.Bootstrap;
import io.netty.channel.ChannelFuture;
import io.netty.channel.ChannelFutureListener;
import io.netty.channel.ChannelInitializer;
import io.netty.channel.EventLoopGroup;
import io.netty.channel.socket.nio.NioDatagramChannel;
import io.netty.handler.ssl.util.SelfSignedCertificate;
import io.netty.handler.timeout.IdleStateHandler;
import io.netty.incubator.codec.quic.InsecureQuicTokenHandler;
import io.netty.incubator.codec.quic.QuicServerCodecBuilder;
import io.netty.incubator.codec.quic.QuicSslContext;
import io.netty.incubator.codec.quic.QuicSslContextBuilder;
import io.netty.incubator.codec.quic.QuicStreamChannel;

import java.net.InetSocketAddress;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Map;
import java.util.concurrent.TimeUnit;


/**
 * NettyServer.
 */
public class QuicNettyServer extends AbstractServer implements RemotingServer {

    private static final Logger logger = LoggerFactory.getLogger(QuicNettyServer.class);
    private static final String SERVER_THREAD_POOL_NAME = "DubboServerHandler";
    /**
     * the cache for alive worker channel.
     * <ip:port, dubbo channel>
     */
    private Map<String, Channel> channels;
    /**
     * netty server bootstrap.
     */
    private Bootstrap bootstrap;
    /**
     * the boss channel that receive connections and dispatch these to worker channel.
     */
    private io.netty.channel.Channel channel;

    private EventLoopGroup bossGroup;
    private EventLoopGroup workerGroup;

    public QuicNettyServer(URL url, ChannelHandler handler) throws RemotingException {
        // you can customize name and type of client thread pool by THREAD_NAME_KEY and THREADPOOL_KEY in CommonConstants.
        // the handler will be wrapped: MultiMessageHandler->HeartbeatHandler->handler
        super(ExecutorUtil.setThreadName(url, SERVER_THREAD_POOL_NAME), ChannelHandlers.wrap(handler, url));
    }

    /**
     * Init and start netty server
     *
     * @throws Throwable
     */
    @Override
    protected void doOpen() throws Throwable {

        bossGroup = QuicNettyEventLoopFactory.eventLoopGroup(1, "QuicNettyServerBoss");

        final QuicNettyServerHandler nettyServerHandler = new QuicNettyServerHandler(getUrl(), this);
        channels = nettyServerHandler.getChannels();


        SelfSignedCertificate selfSignedCertificate = new SelfSignedCertificate();
        QuicSslContext context = QuicSslContextBuilder.forServer(
                selfSignedCertificate.privateKey(), null, selfSignedCertificate.certificate())
            .applicationProtocols("http/0.9").build();


        bootstrap = new Bootstrap();
        io.netty.channel.ChannelHandler codec = new QuicServerCodecBuilder()
            .sslContext(context)
            .maxIdleTimeout(5000, TimeUnit.MILLISECONDS)
            .initialMaxData(10000000)
            .initialMaxStreamDataBidirectionalLocal(1000000)
            .initialMaxStreamDataBidirectionalRemote(1000000)
            .initialMaxStreamsBidirectional(100)
            .initialMaxStreamsUnidirectional(100)
            .tokenHandler(InsecureQuicTokenHandler.INSTANCE)
            .streamHandler(new ChannelInitializer<QuicStreamChannel>() {
                @Override
                protected void initChannel(QuicStreamChannel ch) {
                    int idleTimeout = UrlUtils.getIdleTimeout(getUrl());
                    NettyCodecAdapter adapter = new NettyCodecAdapter(getCodec(), getUrl(), QuicNettyServer.this);
                    ch.pipeline()
                        .addLast("decoder", adapter.getDecoder())
                        .addLast("encoder", adapter.getEncoder())
                        .addLast("server-idle-handler", new IdleStateHandler(0, 0, idleTimeout, TimeUnit.MILLISECONDS))
                        .addLast("handler", nettyServerHandler);
                }
            }).build();

        InetSocketAddress address = getBindAddress();
        logger.info("bind address:" + address);
        ChannelFuture channelFuture = bootstrap.group(bossGroup)
            .channel(NioDatagramChannel.class)
            .handler(codec)
            .bind(address);
        channelFuture.addListener((ChannelFutureListener) channelFuture1 -> logger.info("bind finish:" + channelFuture1));
    }

    @Override
    protected void doClose() throws Throwable {
        try {
            if (channel != null) {
                // unbind.
                channel.close();
            }
        } catch (Throwable e) {
            logger.warn(e.getMessage(), e);
        }
        try {
            Collection<org.apache.dubbo.remoting.Channel> channels = getChannels();
            if (channels != null && channels.size() > 0) {
                for (org.apache.dubbo.remoting.Channel channel : channels) {
                    try {
                        channel.close();
                    } catch (Throwable e) {
                        logger.warn(e.getMessage(), e);
                    }
                }
            }
        } catch (Throwable e) {
            logger.warn(e.getMessage(), e);
        }
        try {
            if (bootstrap != null) {
                bossGroup.shutdownGracefully().syncUninterruptibly();
                workerGroup.shutdownGracefully().syncUninterruptibly();
            }
        } catch (Throwable e) {
            logger.warn(e.getMessage(), e);
        }
        try {
            if (channels != null) {
                channels.clear();
            }
        } catch (Throwable e) {
            logger.warn(e.getMessage(), e);
        }
    }

    @Override
    protected int getChannelsSize() {
        return channels == null ? 0 : channels.size();
    }

    @Override
    public Collection<Channel> getChannels() {
        Collection<Channel> chs = new ArrayList<>(this.channels.size());
        // pick channels from NettyServerHandler ( needless to check connectivity )
        chs.addAll(this.channels.values());
        return chs;
    }

    @Override
    public Channel getChannel(InetSocketAddress remoteAddress) {
        return channels.get(NetUtils.toAddressString(remoteAddress));
    }

    @Override
    public boolean canHandleIdle() {
        return true;
    }

    @Override
    public boolean isBound() {
        return channel.isActive();
    }

}