/**
 * Copyright © 2016-2026 The Thingsboard Authors
 *
 * 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
 *
 *     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.thingsboard.server.transport.mqtt;

import io.netty.bootstrap.ServerBootstrap;
import io.netty.channel.Channel;
import io.netty.channel.ChannelOption;
import io.netty.channel.EventLoopGroup;
import io.netty.channel.nio.NioEventLoopGroup;
import io.netty.channel.socket.nio.NioServerSocketChannel;
import io.netty.util.AttributeKey;
import io.netty.util.ResourceLeakDetector;
import jakarta.annotation.PostConstruct;
import jakarta.annotation.PreDestroy;
import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.boot.autoconfigure.condition.ConditionalOnExpression;
import org.springframework.stereotype.Service;
import org.thingsboard.server.common.data.DataConstants;
import org.thingsboard.server.common.data.TbTransportService;

import java.net.InetSocketAddress;

@Service("MqttTransportService")
@TbMqttTransportComponent
@Slf4j
public class MqttTransportService implements TbTransportService {

    public static AttributeKey<InetSocketAddress> ADDRESS = AttributeKey.newInstance("SRC_ADDRESS");

    @Value("${transport.mqtt.bind_address}")
    private String host;
    @Value("${transport.mqtt.bind_port}")
    private Integer port;

    @Value("${transport.mqtt.ssl.enabled}")
    private boolean sslEnabled;

    @Value("${transport.mqtt.ssl.bind_address}")
    private String sslHost;
    @Value("${transport.mqtt.ssl.bind_port}")
    private Integer sslPort;

    @Value("${transport.mqtt.netty.leak_detector_level}")
    private String leakDetectorLevel;
    @Value("${transport.mqtt.netty.boss_group_thread_count}")
    private Integer bossGroupThreadCount;
    @Value("${transport.mqtt.netty.worker_group_thread_count}")
    private Integer workerGroupThreadCount;
    @Value("${transport.mqtt.netty.so_keep_alive}")
    private boolean keepAlive;

    @Autowired
    private MqttTransportContext context;

    private Channel serverChannel;
    private Channel sslServerChannel;
    private EventLoopGroup bossGroup;
    private EventLoopGroup workerGroup;

    @PostConstruct
    public void init() throws Exception {
        log.info("Setting resource leak detector level to {}", leakDetectorLevel);
        ResourceLeakDetector.setLevel(ResourceLeakDetector.Level.valueOf(leakDetectorLevel.toUpperCase()));

        log.info("Starting MQTT transport...");
        try {
            bossGroup = new NioEventLoopGroup(bossGroupThreadCount);
            workerGroup = new NioEventLoopGroup(workerGroupThreadCount);
            ServerBootstrap b = new ServerBootstrap();
            b.group(bossGroup, workerGroup)
                    .channel(NioServerSocketChannel.class)
                    .childHandler(new MqttTransportServerInitializer(context, false))
                    .childOption(ChannelOption.SO_KEEPALIVE, keepAlive);

            serverChannel = b.bind(host, port).sync().channel();
            if (sslEnabled) {
                b = new ServerBootstrap();
                b.group(bossGroup, workerGroup)
                        .channel(NioServerSocketChannel.class)
                        .childHandler(new MqttTransportServerInitializer(context, true))
                        .childOption(ChannelOption.SO_KEEPALIVE, keepAlive);
                sslServerChannel = b.bind(sslHost, sslPort).sync().channel();
            }
        } catch (Exception e) {
            log.error("Failed to start MQTT transport, releasing resources", e);
            if (e instanceof InterruptedException) {
                Thread.currentThread().interrupt();
            }
            try {
                if (serverChannel != null) {
                    serverChannel.close().sync();
                }
                if (sslServerChannel != null) {
                    sslServerChannel.close().sync();
                }
            } catch (Exception suppressed) {
                e.addSuppressed(suppressed);
            } finally {
                if (workerGroup != null) {
                    workerGroup.shutdownGracefully();
                }
                if (bossGroup != null) {
                    bossGroup.shutdownGracefully();
                }
            }
            throw e;
        }
        log.info("Mqtt transport started!");
    }

    @PreDestroy
    public void shutdown() throws InterruptedException {
        log.info("Stopping MQTT transport!");
        try {
            serverChannel.close().sync();
            if (sslEnabled) {
                sslServerChannel.close().sync();
            }
        } finally {
            workerGroup.shutdownGracefully();
            bossGroup.shutdownGracefully();
        }
        log.info("MQTT transport stopped!");
    }

    @Override
    public String getName() {
        return DataConstants.MQTT_TRANSPORT_NAME;
    }
}
