const MqttSyncClient = require('./mqttClient');
const Framework = require('../../../framework/node-core-framework');
const logs = require('../logProxy');
const appConfig = require('../../../config/config.js');
// action.js 已合并到 mqttDispatcher.js，不再需要单独引入

function buildMqttManagerConfig() {
    const mqttCfg = appConfig.mqtt || {};
    const brokerUrl = (mqttCfg.brokerUrl && String(mqttCfg.brokerUrl).trim())
        ? mqttCfg.brokerUrl.trim()
        : `mqtt://${mqttCfg.host || '192.144.167.231'}:${mqttCfg.port != null ? mqttCfg.port : 1883}`;
    const options = {
        clientId: mqttCfg.clientId || `mqtt_server_${Math.random().toString(16).substr(2, 8)}`,
        clean: mqttCfg.clean !== false,
        connectTimeout: mqttCfg.connectTimeout != null ? mqttCfg.connectTimeout : 5000,
        reconnectPeriod: mqttCfg.reconnectPeriod != null ? mqttCfg.reconnectPeriod : 5000,
        keepalive: mqttCfg.keepalive != null ? mqttCfg.keepalive : 60
    };
    if (mqttCfg.username) {
        options.username = mqttCfg.username;
    }
    if (mqttCfg.password) {
        options.password = mqttCfg.password;
    }
    return { brokerUrl, options };
}

/**
 * MQTT管理器 - 单例模式
 * 负责管理MQTT连接，确保全局只有一个MQTT客户端实例
 */
class MqttManager {
    constructor() {
        this.client = null;
        this.isInitialized = false;
        this.config = buildMqttManagerConfig();
    }

    /**
     * 获取MQTT客户端实例（单例模式）
     * @param {object} config - 可选的配置覆盖
     * @returns {Promise<MqttSyncClient>} MQTT客户端实例
     */
    async getInstance(config = {}) {
        if (this.client && this.isInitialized) {
            const brokerOk = typeof this.client.isBrokerConnected === 'function'
                ? this.client.isBrokerConnected()
                : this.client.isConnected;
            if (!brokerOk) {
                console.warn('[MQTT管理器] 单例已初始化但 Broker 未连接，重置并重建');
                await this.reset();
            } else {
                console.log('[MQTT管理器] 返回已存在的MQTT客户端实例');
                return this.client;
            }
        }

        // 合并配置
        if (config.brokerUrl) {
            this.config.brokerUrl = config.brokerUrl;
        }
        if (config.options) {
            this.config.options = { ...this.config.options, ...config.options };
        }

        try {
            console.log('[MQTT管理器] 创建新的MQTT客户端实例');
            console.log(`[MQTT管理器] Broker地址: ${this.config.brokerUrl}`);

            // 创建MQTT客户端
            this.client = new MqttSyncClient(this.config.brokerUrl, this.config.options);

            // 等待连接成功
            await this.client.waitForConnect(10000);

            // 注意：心跳和响应的订阅已移到 mqttDispatcher 中处理
            // 这里不再直接订阅，由调度系统通过 mqttDispatcher 统一管理
            console.log('[MQTT管理器] MQTT客户端连接成功，等待分发器初始化订阅');

            this.isInitialized = true;
            console.log('[MQTT管理器] MQTT客户端初始化成功');

            return this.client;
        } catch (error) {
            console.error('[MQTT管理器] MQTT客户端初始化失败:', error);
            this.client = null;
            this.isInitialized = false;
            throw error;
        }
    }

    /**
     * 重置MQTT客户端（用于重新连接）
     */
    async reset() {
        if (this.client) {
            try {
                console.log('[MQTT管理器] 关闭现有MQTT连接');
                this.client.end(true);
            } catch (error) {
                console.error('[MQTT管理器] 关闭MQTT连接时出错:', error);
            }
        }

        this.client = null;
        this.isInitialized = false;
        console.log('[MQTT管理器] MQTT客户端已重置');
    }

    /**
     * 检查MQTT客户端是否已初始化
     * @returns {boolean}
     */
    isReady() {
        if (!this.isInitialized || !this.client) {
            return false;
        }
        if (typeof this.client.isBrokerConnected === 'function') {
            return this.client.isBrokerConnected();
        }
        return !!this.client.isConnected;
    }

    /**
     * 更新配置
     * @param {object} config - 新的配置
     */
    updateConfig(config) {
        if (this.isInitialized) {
            console.warn('[MQTT管理器] MQTT客户端已初始化，配置更新需要重置连接');
        }

        if (config.brokerUrl) {
            this.config.brokerUrl = config.brokerUrl;
        }
        if (config.options) {
            this.config.options = { ...this.config.options, ...config.options };
        }

        console.log('[MQTT管理器] 配置已更新:', this.config);
    }

    /**
     * 获取当前配置
     * @returns {object}
     */
    getConfig() {
        return { ...this.config };
    }
}

// 导出单例
const mqttManager = new MqttManager();
module.exports = mqttManager;