// ==UserScript==
// @name           quackulator.js
// @namespace      http://example.org
// @description    tells you your new ratio if you download a torrent without seeding
// @include        http://www.norbits.net/details.php?id=*
// @include        http://norbits.net/details.php?id=*
// @include        https://www.norbits.net/details.php?id=*
// @include        https://norbits.net/details.php?id=*
// ==/UserScript==
(function(){ 
   
    if(location.hostname.indexOf('norbits.net') == -1 || 
        location.pathname.indexOf('/details.php') == -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;
            case 'kB':
                //no point in doing calculations with that low numbers
                gigabytes = 0; 
                break;
            default:
                gigabytes = 0;
                break;
        }
        return gigabytes;

    }
    
    function _t(e) {

       try {
            var tableRow = getNodes('//tr//td[@class="rowhead" and' +
            ' contains(text(), "St") and contains(text(), "rrelse")]/..').snapshotItem(0);

            if(!tableRow) {
                return;
            }
            //<TD class="rowhead">Størrelse</TD><TD valign="top" align="left">5.48 GB (5,887,848,401 bytes)</TD>
            var sizeNode = getNodes('.//td[2]', tableRow).snapshotItem(0);
            
            if(!sizeNode) {
                return;
            }
            
            var activeTorrentsNode = getNodes('//font[text()="Akt:"]').snapshotItem(0);
            if(!activeTorrentsNode){ return;}
            var uploadNode = getNodes('//font[text()="Opp:"]').snapshotItem(0);
            if(!uploadNode){ return;}
            var uploaded = getGigaBytes(uploadNode.nextSibling.textContent);//always in GB


            var downloadNode = getNodes('//font[text()="Ned:"]').snapshotItem(0);
            if(!downloadNode){ return;}
            var downloaded = getGigaBytes(downloadNode.nextSibling.textContent);//always in GB
            //<tr><td class="rowhead">Størrelse</td><td valign="top" align=left>5.48 GB (5,887,848,401 bytes)</td></tr>
            var size = getGigaBytes(sizeNode.textContent);
            var newDownload = Number(downloaded)+ Number(size);
            
            var newRatio = '';
            
            if(uploaded !=0) {
                newRatio = (uploaded/newDownload).toFixed(2);
            } else {
                newRatio = '---';
            }
            
            var arow = document.createElement('tr');
            
            var cell1 = document.createElement('td');
            cell1.className = 'rowhead';
            cell1.appendChild(document.createTextNode('Quackulator'));
            arow.appendChild(cell1);
            
            var cell2 = document.createElement('td');
            cell2.vAlign='top';
            cell2.align = 'left';
            cell2.appendChild(document.createTextNode(newRatio + '<-- ny ratio hvis du laster ned denne uten å seede noe'));
            arow.appendChild(cell2);
            
            tableRow.parentNode.insertBefore(arow, tableRow.nextSibling);
            
        
       } catch(e) {
            alert('feil: ' + e)
       }
    }
   
    if(window.opera) {
        window.addEventListener('DOMContentLoaded', _t, false);    
    } else {
        window.addEventListener('load', _t, false);
   }
})();