package Mqtt.service;

import Mqtt.config.LocalCacheManager;
import Mqtt.config.MQTTConfig;
import lombok.extern.slf4j.Slf4j;
import org.eclipse.paho.client.mqttv3.*;
import org.eclipse.paho.client.mqttv3.persist.MemoryPersistence;
import org.springframework.stereotype.Component;

import javax.annotation.PostConstruct;
import java.nio.charset.StandardCharsets;
import java.util.List;

/**
 * 发布端逻辑
 */
@Component
@Slf4j
public class MqttClientManager {

    private final MQTTConfig config;
    private final LocalCacheManager cacheManager;
    private MqttClient client;

    public MqttClientManager(MQTTConfig config, LocalCacheManager cacheManager) {
        this.config = config;
        this.cacheManager = cacheManager;
    }

    @PostConstruct
    public void init() {
        if (!config.isEnablePublisher()) {
            log.info("发布端初始化已禁用（enablePublisher=false）");
            return;
        }

        try {
            client = new MqttClient(config.getHost(), config.getPublisher().getClientId(), new MemoryPersistence());

            MqttConnectOptions options = buildOptions();
            client.connect(options);
            log.info("发布端连接成功：{}", config.getHost());

            List<String> cachedMessages = cacheManager.loadAll();
            for (String message : cachedMessages) {
                publish(config.getPublisher().getDefaultTopic(), message);
            }
            cacheManager.clearAll();

        } catch (MqttException e) {
            log.error("发布端连接失败：{}", e.getMessage(), e);
        }
    }


    public void publish(String topic, String payload) {
        try {
            if (client == null || !client.isConnected()) {
                log.warn("发布端未连接，缓存消息...");
                cacheManager.cache(payload);
                return;
            }
            MqttMessage message = new MqttMessage(payload.getBytes(StandardCharsets.UTF_8));
            message.setQos(1); // 可配置
            client.publish(topic, message);
            log.info("消息已发布到 {}：{}", topic, payload);
        } catch (Exception e) {
            log.error("发布失败，缓存消息", e);
            cacheManager.cache(payload);
        }
    }

    private MqttConnectOptions buildOptions() {
        MqttConnectOptions options = new MqttConnectOptions();
        options.setCleanSession(config.isCleansession());
        options.setUserName(config.getUsername());
        options.setPassword(config.getPassword().toCharArray());
        options.setKeepAliveInterval(config.getKeepalive());
        options.setConnectionTimeout(config.getConnectionTimeout());
        return options;
    }
}