// ==UserScript==
// @name           add_buffer.js
// @namespace      http://example.org
// @description    adds information about your current buffer
// @include        http://www.norbits.net/
// @include        http://www.norbits.net/*
// @include        http://norbits.net/
// @include        http://norbits.net/*
// ==/UserScript==
(function(){ 
   
   if(location.hostname.indexOf('norbits.net') == -1) {
       return false;
   }
   
   function getNodes(expression, startElement) {
       startElement = startElement || document;
       var nodes = document.evaluate( expression, startElement, null,
                                       XPathResult.ORDERED_NODE_SNAPSHOT_TYPE, null );
       
       return nodes;
   }
   
   function trim(str) {
        return str.replace(/^\s\s*/, '').replace(/\s\s*$/, '');
   
   }
   
   function getGigaBytes(text){
        var gigabytes, numbers, suffix;
        text = trim(text);
        
        if(text == 'Inf.' || text == '---') {
            return 0;
        }
        
        var _tmp = text.split(' ');
        numbers  = Number(_tmp[0]);
        suffix   = _tmp[1];
        //alert('suffix er: "' + suffix + "'")
        switch(suffix){
            case 'GB':
                gigabytes =  numbers;
                break;
            case 'TB':
                gigabytes = numbers*1024;
                break;
            case 'MB':
                gigabytes = numbers*0.0009765625;
                break;
            default:
                gigabytes = numbers;
                break;
            
        
        }
   
        return gigabytes;
   
   }
    
   function _t(e) {
    
       try{
           var activeTorrentsNode = getNodes('//font[text()="Akt:"]').snapshotItem(0);
           
           var uploadNode = getNodes('//font[@color="green" and text()="Opp:"]').snapshotItem(0);
           var uploaded = getGigaBytes(uploadNode.nextSibling.textContent);//always in GB
           
           
           var downloadNode = getNodes('//font[@color="darkred" and text()="Ned:"]').snapshotItem(0);
           var downloaded = getGigaBytes(downloadNode.nextSibling.textContent);//always in GB
           
           var container = document.createElement('span');
           
           var labelContainer = document.createElement('span');
           labelContainer.style.color='purple';
           labelContainer.appendChild(document.createTextNode('Buffer: '));
           container.appendChild(labelContainer);
           
           if(downloaded >= uploaded) {
                container.appendChild(document.createTextNode('---'));
           } else {
                var buffer = Math.round((uploaded-downloaded)*100)/100;//always in GB, two decimals
                container.appendChild(document.createTextNode( buffer+ ' GB'));
           
           }
           container.appendChild(document.createTextNode('  '));
           //insert before activeTorrentsNode
           activeTorrentsNode.parentNode.insertBefore(container, activeTorrentsNode);
           
       }catch(e) {
            alert('feil: ' + e)
       }
   }
   if(window.opera) {
        window.addEventListener('DOMContentLoaded', _t, false);
        
   } else {
        window.addEventListener('load', _t, false);
   }
})();