package com.tencent.tdmq.mqtt.example.paho.v5;

import java.nio.ByteBuffer;
import java.nio.charset.StandardCharsets;
import java.util.List;
import java.util.concurrent.TimeUnit;
import org.eclipse.paho.mqttv5.client.IMqttToken;
import org.eclipse.paho.mqttv5.client.MqttCallback;
import org.eclipse.paho.mqttv5.client.MqttClient;
import org.eclipse.paho.mqttv5.client.MqttConnectionOptions;
import org.eclipse.paho.mqttv5.client.MqttDisconnectResponse;
import org.eclipse.paho.mqttv5.client.persist.MemoryPersistence;
import org.eclipse.paho.mqttv5.common.MqttException;
import org.eclipse.paho.mqttv5.common.MqttMessage;
import org.eclipse.paho.mqttv5.common.packet.MqttProperties;
import org.eclipse.paho.mqttv5.common.packet.UserProperty;

public class SubscriberQuickStart {

    public static void main(String[] args) throws MqttException, InterruptedException {

        // 从MQTT控制台获取接入点:
        // 通过Private Link实现VPC网络打通的用户, 使用内网接入点;
        // 通过公网访问的用户, 确保公网安全策略允许, 程序运行机器由公网接入;
        String serverUri = "tcp://mqtt-xxx.mqtt.tencenttdmq.com:1883";

        // 合法的Client Identifier包含 数字0-9, 小写英文字母a-z, 以及大写英文字母A-Z, 总长度为1-23个字符
        // 参考 https://docs.oasis-open.org/mqtt/mqtt/v5.0/os/mqtt-v5.0-os.html#_Toc3901059
        String clientId = "SubscriberQuickStart";

        // 在控制台 --> 认证 Tab页创建账户, 复制用户名和密码
        String username = "user0";
        String password = "secret0";

        // MQTT topic filters
        String[] topicFilters = new String[]{"home/test", "home/#", "home/+"};
        int[] qos = new int[]{1, 1, 1};

        MqttClient client = new MqttClient(serverUri, clientId, new MemoryPersistence());
        client.setTimeToWait(3000);
        MqttConnectionOptions options = new MqttConnectionOptions();
        options.setUserName(username);
        options.setPassword(password.getBytes(StandardCharsets.UTF_8));
        options.setCleanStart(true);
        options.setAutomaticReconnect(true);

        client.setCallback(new MqttCallback() {
            @Override
            public void disconnected(MqttDisconnectResponse response) {
                System.out.println("Disconnected: " + response.getReasonString());
            }

            @Override
            public void mqttErrorOccurred(MqttException e) {
                e.printStackTrace();
            }

            @Override
            public void messageArrived(String topic, MqttMessage message) {
                byte[] payload = message.getPayload();
                String content;
                if (4 == payload.length) {
                    ByteBuffer buf = ByteBuffer.wrap(payload);
                    content = String.valueOf(buf.getInt());
                } else {
                    content = new String(payload, StandardCharsets.UTF_8);
                }

                System.out.printf("Message arrived, topic=%s, QoS=%d content=[%s]%n",
                    topic, message.getQos(), content);
                List<UserProperty> userProperties = message.getProperties().getUserProperties();
                printUserProperties(userProperties);
            }

            @Override      
            public void deliveryComplete(IMqttToken token) {
                System.out.println("Delivery complete for packet-id: " + token.getMessageId());
            }

            @Override
            public void connectComplete(boolean reconnect, String serverURI) {
                System.out.println(reconnect ? "Reconnected" : "Connected" + " to " + serverURI);
                try {
                    // Subscribe
                    IMqttToken token = client.subscribe(topicFilters, qos);
                    int[] reasonCodes = token.getReasonCodes();
                    for (int i = 0; i < reasonCodes.length; i++) {
                        System.out.printf("Subscribed to topic %s with QoS=%d, Granted-QoS: %d%n",
                            topicFilters[i], qos[i], reasonCodes[i]);
                    }

                    if (token.isComplete()) {
                        List<UserProperty> userProperties = token.getResponseProperties().getUserProperties();
                        printUserProperties(userProperties);
                    }
                } catch (MqttException e) {
                    e.printStackTrace();
                }
            }

            @Override
            public void authPacketArrived(int i, MqttProperties properties) {
                System.out.println("Received auth packet with id: " + i);
            }
        });

        client.connect(options);
        
        TimeUnit.MINUTES.sleep(5);

        client.disconnect();

        client.close();
    }

    static void printUserProperties(List<UserProperty> userProperties) {
        if (null != userProperties) {
            for (UserProperty userProperty : userProperties) {
                System.out.printf("User property: %s = %s%n", userProperty.getKey(), userProperty.getValue());
            }
        }
    }
}

Connected to tcp://mqtt-xxx.mqtt.tencenttdmq.com:1883
Subscribed to topic home/test with QoS=1, Granted-QoS: 1
Subscribed to topic home/# with QoS=1, Granted-QoS: 1
Subscribed to topic home/+ with QoS=1, Granted-QoS: 1

Prepare to publish message 0
Published message 0
Message arrived, topic=home/test, QoS=1 content=[Hello MQTT 0]

Prepare to publish message 1
Published message 1
Message arrived, topic=home/test, QoS=1 content=[Hello MQTT 1]

Prepare to publish message 2
Published message 2
Message arrived, topic=home/test, QoS=1 content=[Hello MQTT 2]

[... 中间消息省略 ...]

Prepare to publish message 14
Published message 14
Message arrived, topic=home/test, QoS=1 content=[Hello MQTT 14]

Prepare to publish message 15
Published message 15
Message arrived, topic=home/test, QoS=1 content=[Hello MQTT 15]

Disconnected: Normal disconnection