var dataOS = [
        {   string: navigator.platform,
			subString: "Win",
			identity: "Windows"
		},
		{   string: navigator.platform,
			subString: "Mac",
			identity: "Mac"
		},		
		{   string: navigator.platform,
			subString: "Linux",
			identity: "Linux"
		},
		{   string: navigator.appVersion,
			subString: "X11",
			identity: "Linux"
		}
];
var platforms = [
        {   string: "Windows (XP & Vista)",
			defaultFor: "Windows",
			arch: "win32.win32"
		},
        {   string: "32-bit Linux",
			defaultFor: "Linux",
			arch:"linux.x86"		
		},
        {   string: "64-bit Linux",
			defaultFor: "",
			arch:"linux.x86_64"
		},
        {   string: "Intel Mac OSX",
			defaultFor: "Mac",
			arch:"macosx.x86"
		},
        {   string: "G3/G4/G5 Mac OSX",
			defaultFor: "",
			arch:"macosx.ppc"	
		}        
];

var OSName="Unknown";
for (var i=0; i<dataOS.length; i++) {
    if (dataOS[i].string.indexOf(dataOS[i].subString)!=-1) {
        OSName=dataOS[i].identity;
    }
}

function getDownloadURL(version,fullversion,arch) {
    return 'http://nwb.slis.indiana.edu/nightly/'+fullversion+'/installers/nwb-installer-'+version+'-'+arch+'.jar';
}

function updateURL(version,fullversion) {
   var select = document.getElementById(version);
   var link = document.getElementById(version+'.download');

   for (var i=0; i<platforms.length; i++) {
        if (select.options[i].selected == true) {   
            link.href=getDownloadURL(version,fullversion,platforms[i].arch);
            return;
        }
    }
}

function createDownloadForm(version,fullversion) {
    document.write('<div class="container"><form>');
    document.write('<div class="downloadbutton"> </div>'); 
    document.write('<div class="downloadbutton2"><center><label>'); 
    document.write('<select name="Choose" type="text" class="download" id="'+version+'" onchange="updateURL(\''+version+"\',\'"+fullversion+'\');">');

    for (var i=0; i<platforms.length; i++) {
        document.write('<option value="'+platforms[i].string+'">'+platforms[i].string+'</option>');
    }

    document.write('</select>');   
    document.write('</label></center></div>');
    
    document.write('<div class="downloadbutton3"><a id="'+version+'.download" href="#" onClick="javascript:urchinTracker(\'/downloads/nwbtool\')"><img border="0" src="images/downloadbutton_03.jpg" width="134" height="61" /></a> </div>');
    document.write('</form></div>');
    
    var select = document.getElementById(version);
    for (var i=0; i<platforms.length; i++) {   
        if (OSName == platforms[i].defaultFor) {
            select.options[i].selected = true;
        }
    }

    updateURL(version,fullversion);
}