/*!
* JS Redirection Mobile
*
* Copyright (c) 2011 Sebastiano Armeli-Battana (http://sebarmeli.com)
* MIT Licensed: http://www.opensource.org/licenses/mit-license.php
* @link http://github.com/sebarmeli/JS-Redirection-Mobile-Site/
*/

/*
* This version is exactly the same as redirection_mobile.js, but it's an anonymous self-executing
* function, and it's using the default values for 'redirection_paramName' ("mobile_redirect"), 'mobile_prefix'("m"),
* 'mobile_url'("") and 'cookie_hour'(1). In this way you can drop this file on your web server with no configuration
*
* @author Sebastiano Armeli-Battana
* @version 0.7
*
*/

/*globals window, redirection_mobile, document, navigator, location */
(function(window, document, navigator) {

// Helper function for adding time to the current date
var addTimeToDate = function(msec) {

// Get the current date
var exdate = new Date();

// Add time to the date
exdate.setTime(exdate.getTime() + msec);

//Return the new Date
return exdate;

};

// Helper function for getting a value from a parameter in the querystring
var getQueryValue = function(param) {

if (!param) {
return;
}

var querystring = document.location.search,
queryStringArray = querystring && querystring.substring(1).split("&"),
i = 0,
length = queryStringArray.length;

for (; i < length; i++) {
var token = queryStringArray[i],
firstPart = token && token.substring(0, token.indexOf("="));
if (firstPart === param ) {
return token.substring(token.indexOf("=") + 1, token.length);
}
}

};

// Retrieve the User Agent of the browser
var agent = navigator.userAgent.toLowerCase(),

// Constants
FALSE = "false",

// parameter to pass in the URL to avoid the redirection
redirection_param = "mobile_redirect",

// new url for the mobile site domain
mobile_url = "m.poweredbywsi.com",

// protocol for the mobile site domain
mobile_protocol = document.location.protocol,

// URL host of incoming request
host = document.location.host,

// value for the parameter passed in the URL to avoid the redirection
queryValue = getQueryValue(redirection_param),

// Compose the mobile hostname considering "mobile_url" or "mobile_prefix" + hostname
mobile_host = mobile_url ||
(mobile_prefix + "." +
(!!host.match(/^www\./i) ?
host.substring(4) :
host)),

// Expiry hours for cookie
cookie_hours = 1,

// Check if the UA is a mobile one (iphone, ipod, ipad, android, blackberry)
isUAMobile =!!(agent.match(/(iPhone|iPod|blackberry|android|htc|kindle|lg|midp|mmp|mobile|nokia|opera mini|palm|pocket|psp|sgh|smartphone|symbian|treo mini|Playstation Portable|SonyEricsson|Samsung|MobileExplorer|PalmSource|Benq|Windows Phone|Windows Mobile|IEMobile|Windows CE|Nintendo Wii)/i));

// Check if the referrer was a mobile page (probably the user clicked "Go to full site") or in the
// querystring there is a parameter to avoid the redirection such as "?mobile_redirect=false"
// (in that case we need to set a variable in the sessionStorage or in the cookie)
if (document.referrer.indexOf(mobile_host) >= 0 || queryValue === FALSE ) {

if (window.sessionStorage) {
window.sessionStorage.setItem(redirection_param, FALSE);
} else {
document.cookie = redirection_param + "=" + FALSE + ";expires="+
addTimeToDate(3600*1000*cookie_hours).toUTCString();
}
}

// Check if the sessionStorage contain the parameter
var isSessionStorage = (window.sessionStorage) ?
(window.sessionStorage.getItem(redirection_param) === FALSE) :
false,

// Check if the Cookie has been set up
isCookieSet = document.cookie ?
(document.cookie.indexOf(redirection_param) >= 0) :
false;

// Check that User Agent is mobile, cookie is not set or value in the sessionStorage not present
if (isUAMobile && !(isCookieSet || isSessionStorage)) {
document.location.href = mobile_protocol + "//" + mobile_host;
}

}(window, document, navigator));