Pinkie Pie Bot

/* MADE BY FLUTTERSHY.PL */
//feel free to improve this code. Remember to share your results!
/* PNGJS is a lazy, temporary solution. The intended way is transforming original BMP structure of bigchunk.bmp .*/
//required modules, get pngjs and discord.js using npm
const Discord = require('discord.js');
const HTTP = require('http');
const PNG = require('pngjs').PNG;

//RGB values of colours used by pixelcanvas
const red = [255,228,136,34,255,229,229,160,229,148,2,0,0,0,207,130];
const green = [255,228,136,34,167,0,149,106,217,224,190,211,131,0,110,0];
const blue = [255,228,136,34,209,0,0,66,0,68,1,221,199,234,228,128];

//user configuration, maximum dimentions that won't get scaled down by Discord are 400 width 300 height, maximum for the bot is 897 width 897 height
const token = ''; //token from discord developer API
const w = 400;
const h = 120;


//actual bot code
const client = new Discord.Client();
client.on('ready', () => {
    console.log("Successfully connected to Discord!");
});

function sendSnapshot(x,y,channel){
    console.log("Somepony requested @"+x+","+y)
    var topLeftX = parseInt(x-(w/2));
    var offsetLeft = ((topLeftX+448)%64)+((topLeftX<448)*64)
    var bigChunkX = parseInt((topLeftX+448)/64)+(topLeftX>=448);
    var topLeftY = parseInt(y-(h/2));
    var offsetTop = ((topLeftY+448)%64)+((topLeftY<448)*64)
    var bigChunkY = parseInt((topLeftY+448)/64)+(topLeftY>=448);
    HTTP.get('http://pixelcanvas.io/api/bigchunk/'+bigChunkX+'.'+bigChunkY+'.bmp',function(response){
        var data = [];
        response.on('data',function(chunk){
            data.push(chunk);
        });
        response.on('end',function(){
            var buffer = Buffer.concat(data);
            var pngimg = new PNG({
                width: w,
                height: h,
                filterType: -1
            });
            for (var y = 0; y < pngimg.height; y++)
                for (var x = 0; x < pngimg.width; x++) {
                    var i = (pngimg.width * y + x) << 2;
                    var byteOffset = ((parseInt((offsetTop+y)/64)*15+parseInt((offsetLeft+x)/64))*4096+64*((offsetTop+y)%64)+((offsetLeft+x)%64))/2;
                    var colourId = byteOffset%1!=0?buffer[parseInt(byteOffset)]&15:buffer[parseInt(byteOffset)]>>4;
                    pngimg.data[i] = red[colourId];
                    pngimg.data[i+1] = green[colourId];
                    pngimg.data[i+2] = blue[colourId];
                    pngimg.data[i+3] = 0xff;
                }
            var att = new Discord.Attachment(pngimg.pack(),"snapshot.png");
            channel.send("",att);
        });
    });
}

client.on('message', message => {
    var index = message.content.indexOf("pixelcanvas.io/@");
    while(index>-1){
        var failed = false;
        index += 0x10;
        var paramX="";
        var paramY="";
        if(message.content[index]=="-")
            paramX+=message.content[index++];
        if(isNaN(message.content[index]))
            failed = true;
        else {
            while(!isNaN(message.content[index]))
                paramX += message.content[index++];
            paramX = (paramX);
            if(message.content[index++]!=",")
                failed = true;
            else {
                if(message.content[index]=="-")
                    paramY += message.content[index++];
                if(isNaN(message.content[index]))
                    failed = true;
                else {
                    while(!isNaN(message.content[index]))
                        paramY += message.content[index++];
                }
            }
        }
        if(!failed)
            sendSnapshot(parseInt(paramX),parseInt(paramY),message.channel);
        message.content = message.content.substring(index);
        index = message.content.indexOf("pixelcanvas.io/@");
    }
});

client.login(token);