// ==UserScript==
// @name          Gazelle Buffer Calculator
// @description   Shows buffer till demotion with the assumption that user is power user or higher
// @version       5.1
// @author        gblack (originally written by Pinguen and then modified by TankC, updated to use new required and demotion ratios by gblack, a minor edit in buffer calculus by Etheryte)
// @namespace     passtheheadphones.m
// @include       https://passtheheadphones.me/*
// @include       https://notwhat.cd/*
// @include       https://apollo.rip/*
// @include       https://hydra.zone/*
// @include       https://libble.me/*
// @include       https://lztr.me/*
// @downloadURL https://update.greasyfork.icu/scripts/26610/Gazelle%20Buffer%20Calculator.user.js
// @updateURL https://update.greasyfork.icu/scripts/26610/Gazelle%20Buffer%20Calculator.meta.js
// ==/UserScript==

const ratio = 1.05;
const KB = Math.pow(2,10);
const MB = Math.pow(2,20);
const GB = Math.pow(2,30);
const TB = Math.pow(2,40);
const PB = Math.pow(2,50);

// getClass() function modified from webmasterworld.com/forum91/1729.htm
function getClass(name) {
  var allPageTags=document.getElementsByTagName("*");
  for (i=0; i<allPageTags.length; i++) {
    if ( allPageTags[i].className == name ) return allPageTags[i];
  }
}


// convert from format (amount units) to bytes
function toBytes(amount) {
  var bytes = amount[0];

  if ( amount[1] == "KB" ) bytes = amount[0] * KB;
    else if ( amount[1] == "MB" ) bytes = amount[0] * MB;
    else if ( amount[1] == "GB" ) bytes = amount[0] * GB;
    else if ( amount[1] == "TB" ) bytes = amount[0] * TB;
    else if ( amount[1] == "PB" ) bytes = amount[0] * PB;

    return bytes;
}


// convert from bytes to whatever is appropriate, appended with units used
function fromBytes(bytes) {
  var buffer = bytes;
  var units = 'B';

  if ( Math.abs(bytes) >= PB ) {
    buffer = bytes/PB;
    units = "PB";
  } else if ( Math.abs(bytes) >= TB ) {
    buffer = bytes/TB;
    units = "TB";
  } else if ( Math.abs(bytes) >= GB ) {
    buffer = bytes/GB;
    units = "GB";
  } else if ( Math.abs(bytes) >= MB ) {
    buffer = bytes/MB;
    units = "MB";
  } else if ( Math.abs(bytes) >= KB ) {
    buffer = bytes/KB;
    units = "KB";
  }

  return buffer.toFixed(2) + ' ' + units;
}


// sets the color based on the amount, similar to ratio coloring
function spanColor(bytes) {
var r_class;

if ( bytes > (100 * GB) ) r_class = 'r50';
else if ( bytes > (10 * GB) ) r_class = 'r10'; // was r20
else if ( bytes > 0 ) r_class = 'r09'; // was r10
else if ( bytes > (-1 * GB) ) r_class = 'r05';
else r_class = 'r00';

return r_class;
}

// calculate, format and return buffer
function calcBuffer(up, down, target) {

  var upload   = up.split(' ');
  var download = down.split(' ');
  var buffer;
  // convert everything to bytes and find the buffer, then convert back to appropriate units

  if (target == 0) {
    var buffer_bytes = toBytes(upload) - toBytes(download);
    buffer = fromBytes(buffer_bytes);
  }
  else {
    var buffer_bytes = (toBytes(upload)/target) - toBytes(download);
    buffer = fromBytes(buffer_bytes);
  }

  // get some color
  var r_class = spanColor(buffer_bytes);

  return '<span class="' + r_class + '">' + buffer + '</span>';
}

var myStats = document.getElementById('userinfo_stats');
var myUp   = myStats.getElementsByTagName('li')[0].getElementsByTagName('span')[0].innerHTML;
var myDown = myStats.getElementsByTagName('li')[1].getElementsByTagName('span')[0].innerHTML;


var myDemBufferLi = document.createElement('li');
myDemBufferLi.className = 'my_demBuffer';
myDemBufferLi.innerHTML = ' Buffer: <span class="stat">' + calcBuffer(myUp, myDown, ratio);


myStats.appendChild(myDemBufferLi);