import mqtt_module from 'mqtt'

const Mqtt = function (url) {
    this.mqtt = mqtt_module
    this.random = getGuid32;
    this.clientId = getGuid32();
    let options = {
        clientId: this.clientId,
        username: 'test',
        password: 'test',
        connectTimeout: 100,
        keepalive: 100
    }
    this.client = this.mqtt.connect("ws://" + url + "/mqtt", options)
    // 重连次数 超5次就算了
    this.reconnectNum = 0
    // 连接
    this.link = function () {
        return new Promise((resolve, reject) => {
            this.client.on('connect', e => {
                console.log('-----------------------链接成功-----------------------')
                resolve(this.client)
            })
            this.client.on('reconnect', error => {
                this.reconnectNum++
                if (this.reconnectNum >= 10) this.client.end(true)
                console.log('正在重连:', error)
            })
            this.client.on('error', error => {
                console.log('订阅失败', error)
            })
        })
    }
    this.subscribe = function (topic, options) {
        this.client.subscribe(topic, options, (err) => {
            if (!err) {
                console.log('-----------------------'+topic+'订阅成功-----------------------')
            } else {
                throw new Error(err)
            }
        })
    }
    this.unsubscribe = function(topic, options) {
        this.client.unsubscribe(topic, options, (err) => {
            if (!err) {
                console.log('-----------------------'+topic+'取消订阅成功-----------------------')
            } else {
                throw new Error(err)
            }
        })
    }
    this.publish = function (topic, sendMsg, options) {
        this.client.publish(topic, JSON.stringify(sendMsg), options, (err, a) => {
            if (!err) {
                console.log('-----------------------'+topic+'发送成功-----------------------')
            } else {
                throw new Error(err)
            }
        })
    }
    this.message = function (callback) {
        this.client.on('message', (topic, message) => {
            let data = JSON.parse(message.toString())
            callback(data, topic)
        })
    }
    // 关闭
    this.close = function () {
        this.client.end(true)
    }
}

export default Mqtt

function getGuid32() {
    var rt_str = String.fromCharCode(65 + Math.floor(Math.random() * 26));
    for (var i = 0; i < 31; ++i) {
        var num = Math.floor(Math.random() * (26 + 26 + 10));
        var ch_str;
        if (num < 10) {
            ch_str = num.toString();
        } else if (num < 10 + 26) {
            ch_str = String.fromCharCode(65 + num - 10);
        } else {
            ch_str = String.fromCharCode(97 + num - 10 - 26);
        }
        rt_str += ch_str;
    }
    return rt_str;
}