Simple switch between lang php with cookies - php

Question

First I would like to check which language the user is using at the moment (which I have done).
After that if the language isn't the same as the website, overlay with a message that should pop up with question
Do you want change to your language ? click here
The link should redirect to another domain.
If the user choose to be redirected to another domain let's say DE, cookies should keep that settings at least one month and always redirect that user to DE domain even if he enter the main domain.
Here is what I have for now:
<?php
$cookie_name = "user";
$cookie_value = "";
setcookie($cookie_name, $cookie_value, time() + (86400*36) , "/"); // 86400 = 1 day
?>
<?php
$lang = substr($_SERVER['HTTP_ACCEPT_LANGUAGE'], 0, 2);
switch ($lang){
case "pl":
//echo "PAGE FR";
$domain = 'click here';
break;
case "en":
$domain = 'click here';
break;
default:
$domain = 'click here';
break;
}
HTML
<div class='overlay'>You are using ENG lang atm do you want switch to ?
<?php echo $domain; ?> </div>

Answer 1

First, you have to save the users selection
I would do this with a page between the destination and your current page. For example the link to your one other domain would be http://example.com/changelang.php?target=domain1
there you save the cookie with the desired language
if(isset($_GET['target']) AND $_GET['target'] == 'domain1')
{
setcookie($cookie_name, "domain1", time() + (86400*36) , "/"); // 86400 = 1 day
and the redirect to this page
header('Location: http://de.domain1.com/');
exit;
}
Second, you have to check if there is an existing cookie
<?php
if(isset($_COOKIE[$cookie_name]))
{
//do switch here
switch($_COOKIE[$cookie_name])
{
case 'de':
//redirect to other page
header('Location: http://de.domain1.com/');
exit;
break; //this is useless
}
}