const mqtt = require('mqtt')
const { v4: uuidv4 } = require('uuid'); // 顶部添加
const Framework = require('../../../framework/node-core-framework');
const logs = require('../logProxy');

// 获取logsService
class MqttSyncClient {
    constructor(brokerUrl, options = {}) {
        this.client = mqtt.connect(brokerUrl, options)
        this.isConnected = false
        /** @type {string[]} 需在每次 connect（含重连）后向 Broker 幂等订阅的主题 */
        this._maintainedTopics = []
        /** 最近一次收到任意 `response` 主题消息的时间（用于超时日志关联） */
        this.lastResponseAt = null

        // 使用 Map 结构优化消息监听器，按 topic 分组
        this.messageListeners = new Map(); // Map<topic, Set<listener>>
        this.globalListeners = new Set(); // 全局监听器（监听所有 topic）

        const ts = () => new Date().toISOString()
        const markDisconnected = (reason) => {
            this.isConnected = false
            console.warn(`[MQTT] ${ts()} 连接不可用 reason=${reason}`)
        }

        this.client.on('connect', () => {
            this.isConnected = true
            console.log(`[MQTT] ${ts()} 服务端已连接（含重连后的 connect）`)
            this._resubscribeMaintainedTopics()
        })

        this.client.on('reconnect', () => {
            console.log(`[MQTT] ${ts()} 正在重连 Broker...`)
        })

        this.client.on('offline', () => {
            markDisconnected('offline')
        })

        this.client.on('disconnect', () => {
            markDisconnected('disconnect')
        })

        this.client.on('close', () => {
            markDisconnected('close')
        })

        this.client.on('end', () => {
            markDisconnected('end')
        })

        this.client.on('message', (topic, message) => {

            let messageObj;
            try {
                messageObj = JSON.parse(message.toString());
            } catch (error) {
                console.warn('[MQTT] 消息解析失败:', error.message);
                return;
            }

            if (topic === 'response') {
                this.lastResponseAt = Date.now()
            }

            // 1. 触发该 topic 的专用监听器
            const topicListeners = this.messageListeners.get(topic);
            if (topicListeners && topicListeners.size > 0) {
                topicListeners.forEach(listener => {
                    try {
                        listener(topic, messageObj);
                    } catch (error) {
                        console.error('[MQTT] Topic监听器执行失败:', error.message);
                    }
                });
            }

            // 2. 触发全局监听器
            if (this.globalListeners.size > 0) {
                this.globalListeners.forEach(listener => {
                    try {
                        listener(topic, messageObj);
                    } catch (error) {
                        console.error('[MQTT] 全局监听器执行失败:', error.message);
                    }
                });
            }

        })

        this.client.on('error', (err) => {
            console.warn(`[MQTT] ${ts()} Error:`, err && err.message ? err.message : err)
        })
    }

    /**
     * 与 mqtt.js 原生 connected 对齐，供单例健康检查
     */
    isBrokerConnected() {
        return !!(this.client && this.client.connected)
    }

    /**
     * 注册需在每次 connect 后向 Broker 重新声明订阅的主题（不重复注册消息监听器）
     * @param {string[]} topics
     */
    setMaintainedTopics(topics) {
        this._maintainedTopics = Array.isArray(topics) ? [...topics] : []
    }

    _resubscribeMaintainedTopics() {
        if (!this._maintainedTopics.length) return
        if (!this.client || !this.client.connected) return
        const ts = new Date().toISOString()
        for (const topic of this._maintainedTopics) {
            this.client.subscribe(topic, { qos: 0 }, (err, granted) => {
                if (err) {
                    console.warn(`[MQTT] ${ts} ensureSubscriptions 订阅失败 topic=${topic}`, err.message || err)
                } else {
                    console.log(`[MQTT] ${ts} ensureSubscriptions 已订阅 topic=${topic}`, granted)
                }
            })
        }
    }

    waitForConnect(timeout = 5000) {
        return new Promise((resolve, reject) => {
            if (this.isBrokerConnected()) {
                this.isConnected = true
                return resolve()
            }
            const timer = setTimeout(() => {
                reject(new Error('MQTT connect timeout'))
            }, timeout)
            const check = () => {
                if (this.isBrokerConnected()) {
                    this.isConnected = true
                    clearTimeout(timer)
                    resolve()
                } else {
                    setTimeout(check, 100)
                }
            }
            check()
        })
    }

    publish(topic, message, options = {}) {
        return new Promise((resolve, reject) => {
            this.client.publish(topic, message, options, (err) => {
                if (err) reject(err)
                else resolve()
            })
        })
    }

    subscribe(topic, callback = null, options = {}) {
        return new Promise((resolve, reject) => {
            this.client.subscribe(topic, options, (err, granted) => {
                if (err) {
                    reject(err)
                } else {
                    // 如果提供了回调函数，添加到消息监听器
                    if (callback && typeof callback === 'function') {
                        const messageHandler = (responseTopic, message) => {
                            if (responseTopic !== topic) return
                            try {
                                callback(topic, message)
                            } catch (error) {
                                console.warn(`[MQTT] 处理订阅消息失败: ${error.message}`)
                            }
                        }

                        // 添加到消息监听器
                        this.addMessageListener(messageHandler)

                        // 在订阅成功后返回订阅信息和消息处理器
                        resolve({ granted, messageHandler, topic })
                    } else {
                        resolve(granted)
                    }
                }
            })
        })
    }

    /**
     * 发布指令并等待某个主题返回（模拟同步），通过uuid确定唯一项
     * @param {*} requestTopic 
     * @param {*} requestMessage 
     * @param {*} responseTopic 
     * @param {*} timeout 
     */
    async publishAndWait(sn_code, requestMessage, timeout = 60 * 3 * 1000) {
        return new Promise((resolve, reject) => {
            console.log(`[MQTT指令] 发送到主题: request_${sn_code}`, requestMessage);


            const uuid = uuidv4();

            // 将uuid加入消息体，建议使用JSON格式
            const msgObj = typeof requestMessage === 'object'
                ? { ...requestMessage, uuid }
                : { data: requestMessage, uuid };


            const sendMsg = JSON.stringify(msgObj);


            const timer = setTimeout(() => {
                this.removeMessageListener(onMessage);
                const last = this.lastResponseAt
                const extra = last
                    ? ` lastResponseAt=${new Date(last).toISOString()} brokerConnected=${this.isBrokerConnected()}`
                    : ` brokerConnected=${this.isBrokerConnected()}`
                console.warn(`[MQTT] ${new Date().toISOString()} publishAndWait 超时 uuid=${uuid} topic=request_${sn_code}${extra}`)
                reject(new Error('Timeout waiting for response' + (last ? `; lastResponseAt=${new Date(last).toISOString()}` : '')));
            }, timeout);

            const onMessage = (topic, message) => {
                let { uuid: responseUuid } = message
                if (topic === 'response' && responseUuid === uuid) {
                    clearTimeout(timer);
                    this.removeMessageListener(onMessage);
                    resolve(message)
                }
            }

            this.addMessageListener(onMessage)

            this.publish(`request_${sn_code}`, sendMsg).catch(err => {
                clearTimeout(timer);
                this.removeMessageListener(onMessage);
                reject(err);
            });



        });
    }

    /**
     * 添加消息监听器
     * @param {Function} fn - 监听器函数
     * @param {string} topic - 可选，指定监听的 topic，不指定则监听所有
     */
    addMessageListener(fn, topic = null) {
        if (typeof fn !== 'function') {
            throw new Error('监听器必须是函数');
        }

        if (topic) {
            // 添加到特定 topic 的监听器
            if (!this.messageListeners.has(topic)) {
                this.messageListeners.set(topic, new Set());
            }
            this.messageListeners.get(topic).add(fn);
        } else {
            // 添加到全局监听器
            this.globalListeners.add(fn);
        }
    }

    /**
     * 移除消息监听器
     * @param {Function} fn - 监听器函数
     * @param {string} topic - 可选，指定从哪个 topic 移除
     */
    removeMessageListener(fn, topic = null) {
        if (topic) {
            // 从特定 topic 移除
            const topicListeners = this.messageListeners.get(topic);
            if (topicListeners) {
                topicListeners.delete(fn);
                // 如果该 topic 没有监听器了，删除整个 Set
                if (topicListeners.size === 0) {
                    this.messageListeners.delete(topic);
                }
            }
        } else {
            // 从全局监听器移除
            this.globalListeners.delete(fn);

            // 也尝试从所有 topic 中移除（兼容旧代码）
            for (const [topicKey, listeners] of this.messageListeners.entries()) {
                listeners.delete(fn);
                if (listeners.size === 0) {
                    this.messageListeners.delete(topicKey);
                }
            }
        }
    }

    /**
     * 取消订阅主题
     * @param {string} topic 要取消订阅的主题
     * @param {object} subscriptionInfo 订阅时返回的订阅信息
     */
    async unsubscribe(topic, subscriptionInfo = null) {
        return new Promise((resolve, reject) => {
            this.client.unsubscribe(topic, (err) => {
                if (err) {
                    reject(err)
                } else {
                    // 如果提供了订阅信息，移除对应的消息处理器
                    if (subscriptionInfo && subscriptionInfo.messageHandler) {
                        this.removeMessageListener(subscriptionInfo.messageHandler)
                    }
                    resolve()
                }
            })
        })
    }

    end(force = false) {
        this.isConnected = false
        this.client.end(force)
    }
}

module.exports = MqttSyncClient