import mqtt from 'mqtt'
import config from '../config/config.js'
import request from 'request';

export default class MqttManager{

    constructor(){}

    init(){
        this.messageHandlers = []

        this.client = mqtt.connect(config.mqtt.url, config.mqtt.options)
        console.log("[MQTT] Connected to MQTT broker ["+config.mqtt.url+"].");
        this.ready = true

        this.client.on('message', (topic, message) => {
            if(this.getSubscribedTopics().includes(topic)){
                console.log("[MQTT] Got message ["+message+"] on handled topic ["+topic+"].");
                const suitingMessageHandlers = this.messageHandlers.filter(handler => handler.topic == topic && handler.message == message);
                suitingMessageHandlers.forEach(handler => {
                    console.log("[MQTT] Sending web request ["+handler.requestUrl+"].");
                    request(handler.requestUrl, { json: true }, (err, res, body) => {
                        if (err) { 
                            console.log("[MQTT] Error sending web request ["+handler.requestUrl+"].");
                        }else{
                            console.log("[MQTT] Sent web request ["+handler.requestUrl+"].");
                        }
                    });
                });
            }else{
                console.log("[MQTT] Got message ["+message+"] on unhandled topic ["+topic+"].");
            }
        });
    }

    subscribe(topic){
        this.client.subscribe(topic, function(err){
            if(err != null){
                console.log("[MQTT] Error subscribing to topic ["+topic+"].");
            }else{
                console.log("[MQTT] Subscribed to topic ["+topic+"].");
            }
        });
    }

    unsubscribe(topic){
        this.client.unsubscribe(topic, function(err){
            if(err != null){
                console.log("[MQTT] Error unsubscribing to topic ["+topic+"].");
            }else{
                console.log("[MQTT] Unsubscribed to topic ["+topic+"].");
            }
        });
    }

    publishMessage(topic, message){
        this.client.publish(topic, message);
        console.log("[MQTT] Publishing message ["+message+"] in topic ["+topic+"].");
    }

    getSubscribedTopics(){
        return this.messageHandlers.map(h => h.topic);
    }

    addMessageHandler(messageHandler){
        if(!this.getSubscribedTopics().includes(messageHandler.topic)){
            this.subscribe(messageHandler.topic)
        }
        this.messageHandlers.push(messageHandler);
        console.log("[MQTT] Added new message handler ["+JSON.stringify(messageHandler)+"].");
        
    }

    removeMessageHandler(messageHandler){
        const messageHandlerIndex = this.messageHandlers.findIndex(handler => handler.topic == messageHandler.topic && handler.message == messageHandler.message && handler.requestUrl == messageHandler.requestUrl);
        if(messageHandlerIndex != -1){
            this.messageHandlers = this.messageHandlers.splice(messageHandlerIndex,1);
            console.log("[MQTT] Removed message handler ["+JSON.stringify(messageHandler)+"].");
        }else{
            console.log("[MQTT] Error removing message handler ["+JSON.stringify(messageHandler)+"].");
        }
        if(!this.getSubscribedTopics().includes(messageHandler.topic)){
            this.unsubscribe(messageHandler.topic)
        }
    }

}