(function($) {
    if ($.jQT)
    {
        $.jQT.addExtension(function Offline(){
            
            // Convenience array of status values
            var cacheStatusValues = [];
            cacheStatusValues[0] = 'uncached';
            cacheStatusValues[1] = 'idle';
            cacheStatusValues[2] = 'checking';
            cacheStatusValues[3] = 'downloading';
            cacheStatusValues[4] = 'updateready';
            cacheStatusValues[5] = 'obsolete';

            // Listeners for all possible events
            var cache = window.applicationCache;
            cache.addEventListener('cached', logEvent, false);
            cache.addEventListener('checking', logEvent, false);
            cache.addEventListener('downloading', logEvent, false);
            cache.addEventListener('error', logEvent, false);
            cache.addEventListener('noupdate', logEvent, false);
            cache.addEventListener('obsolete', logEvent, false);
            cache.addEventListener('progress', logEvent, false);
            cache.addEventListener('updateready', logEvent, false);

            // Log every event to the console
            function logEvent(e) {
                var online, status, type, message;
                online = (isOnline()) ? 'yes' : 'no';
                status = cacheStatusValues[cache.status];
                type = e.type;
                message = 'online: ' + online;
                message+= ', event: ' + type;
                message+= ', status: ' + status;
                if (type == 'error' && navigator.onLine) {
                    message+= ' There was an unknown error, check your Cache Manifest.';
                }
                console.log(message);
            }
            
            function isOnline() {
                return navigator.onLine;
            }
            
            if (!$('html').attr('manifest')) {
                console.log('No Cache Manifest listed on the <html> tag.');
            }

            // Swap in newly download files when update is ready
            cache.addEventListener('updateready', function(e){
                    // Don't perform "swap" if this is the first cache
                    if (cacheStatusValues[cache.status] != 'idle') {
                        cache.swapCache();
                        console.log('Swapped/updated the Cache Manifest.');
                    }
                }, false);

            // These two functions check for updates to the manifest file
            function checkForUpdates(){
                cache.update();
            }
            function autoCheckForUpdates(){
                setInterval(function(){cache.update();}, 10000);
            }

            return {
                isOnline: isOnline,
                checkForUpdates: checkForUpdates,
                autoCheckForUpdates: autoCheckForUpdates
            };
        });
    }
})($);