/*

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 Created by David Kaneda <http://www.davidkaneda.com>
 Documentation and issue tracking on Google Code <http://code.google.com/p/jqtouch/>

 Special thanks to Jonathan Stark <http://jonathanstark.com/>

 Lots of this code is specifically derived from Jonathan's book,
 "Building iPhone Apps with HTML, CSS, and JavaScript"

 (c) 2009 by jQTouch project members.
 See LICENSE.txt for license.

 */

(function($)
{
    if($.jQTouch)
    {
        $.jQTouch.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
            }
        });
    }
})(jQuery);