const http = require('http')
const url = require('url')
const fs = require('fs')
const ws = require('ws')
const redis = require('redis')
const mime = require('mime')
const XMLHttpRequest = require("xmlhttprequest").XMLHttpRequest

const host = 'http://127.0.0.1:8080/'
const outpath = ['sym', '', 'manifest.json', 'admin', 'stats', 'analytics']

let led1_status = 'off';

//redis client
const redis_cli = redis.createClient({
    host: 'redis',
    port: 6379
})
redis_cli.on("error", function (error) {
    console.error(error)
})

//HTTP server
http.createServer(function (req, res) {
    const q = url.parse(req.url, true);
    let filename = "./public" + q.pathname;
    let path_split = q.pathname.split("/", 4);
    if (path_split[path_split.length - 1] === "") filename += "/index.html";
    let file_type = mime.getType(filename)
    if (path_split[1] === "connect" && path_split[2] !== "") { //device registration
        res.writeHead(200, {'Content-Type': file_type});
        redis_cli.hmset("device;" + path_split[3], "status", "online", "ip", path_split[2], "time", Date.now())
        wss.clients.forEach(clients => {
            clients.send("device;"+path_split[3]+";online")
        })
        res.write("200");
        /*let check = setInterval(to => {
            let xhr = new XMLHttpRequest();
            xhr.open('GET', `http://192.168.1.210/info`, true);
            xhr.timeout = 1000;
            xhr.ontimeout = function(e) {ws.send('error;device "led1" is offline')}
            xhr.send();
            setTimeout(to => {if (xhr.readyState !== 4){
                //ws.send('error;device "led1" took too long to reach')
                wss.clients.forEach(clients => {
                    clients.send('device;led1;offline')
                })
                xhr.abort()
                clearInterval(check)
            }}, 2000)
        }, 5000)*/
        return res.end();
    }
    fs.readFile(filename, function(err, data) {
        if (err) {
            res.writeHead(404, {'Content-Type': "text/html"});
            return res.end("404 Not Found");
        }
        res.writeHead(200, {'Content-Type': file_type});
        res.write(data);
        return res.end();
    })
}).listen(8080);

//WS server
const wss = new ws.Server({
    port: 8081,
    perMessageDeflate: {
        zlibDeflateOptions: {
            // See zlib defaults.
            chunkSize: 1024,
            memLevel: 7,
            level: 3
        },
        zlibInflateOptions: {
            chunkSize: 10 * 1024
        },
        // Other options settable:
        clientNoContextTakeover: true, // Defaults to negotiated value.
        serverNoContextTakeover: true, // Defaults to negotiated value.
        serverMaxWindowBits: 10, // Defaults to negotiated value.
        // Below options specified as default values.
        concurrencyLimit: 10, // Limits zlib concurrency for perf.
        threshold: 1024 // Size (in bytes) below which messages
        // should not be compressed.
    }
});

//check available devices
let checkstat = setInterval(to => {
    redis_cli.keys("device;*", function(err, keys) { if(err) console.log(err)
        if(keys){ keys.forEach(key => {
            redis_cli.hgetall(key, function(err, device) { if(err) console.log(err)
                if (device){
                    let device_available = "online"
                    let xhr = new XMLHttpRequest();
                    xhr.open('GET', `http://${device[3]}/info`, true);
                    xhr.timeout = 1000;
                    xhr.ontimeout = function(e) {ws.send('error;device "led1" is offline')}
                    xhr.send();
                    setTimeout(to => {if (xhr.readyState !== 4){
                        device_available = "offline"
                        xhr.abort()
                    }
                    if (device_available !== device[1]){
                        wss.clients.forEach(clients => clients.send(`${key};${device_available}`))
                    }}, 2000)
                }
            })
        })}
    })
}, 5000)

//WS handler
wss.on('connection', ws => {
    ws.on('message', message => {
        console.log(`Received message => ${message}`)
        let msg = message.split(";", 2)
        if (msg[0] === 'led1') {
            if (msg[1] === '') ws.send('error;try again')
            else if (msg[1] === 'on' || msg[1] === "off"){
                let xhr = new XMLHttpRequest();
                xhr.onreadystatechange = function() {
                    if (xhr.readyState === 4 && xhr.status === 200) {
                        wss.clients.forEach(clients => {
                            clients.send(message)
                        })
                    }
                }
                xhr.open('GET', `http://192.168.1.210/${msg[1]}`, true);
                xhr.timeout = 1000;
                xhr.ontimeout = function(e) {ws.send('error;device "led1" is offline')}
                xhr.send();
                setTimeout(to => {if (xhr.readyState !== 4){
                    ws.send('error;device "led1" took too long to reach')
                    ws.send('device;led1;offline')
                    xhr.abort()
                }}, 1500)
            }else ws.send('error;try again')
        }
    })
    ws.send('websocket connected')
    ws.send(`led1;${led1_status}`)
})

//random key
function get_key(length) {
    let forbidden = false; let output = ''
    let characters = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789'
    do{
        for (let i = 0; i < length; i++ )
            output += characters.charAt(Math.floor(Math.random() * characters.length))
        for (let i = 0; i < output.length; i++) if (output === outpath[i]) forbidden = true
        redis_cli.hget("surl;"+output, "url", function(err, obj) {
            if(err) console.log(err)
            if(obj) forbidden = true
        })
    } while (forbidden)
    return output
}