/*
 * The facebook_onload statement is printed out in the PHP. If the user's logged in
 * status has changed since the last page load, then refresh the page to pick up
 * the change.
 *
 * This helps enforce the concept of "single sign on", so that if a user is signed into
 * Facebook when they visit your site, they will be automatically logged in -
 * without any need to click the login button.
 *
 * @param already_logged_into_facebook  reports whether the server thinks the user
 *                                      is logged in, based on their cookies
 *
 */
function facebook_onload(already_logged_into_facebook) {
  // user state is either: has a session, or does not.
  // if the state has changed, detect that and reload.
  FB.ensureInit(function() {
      FB.Facebook.get_sessionState().waitUntilReady(function(session) {
          var is_now_logged_into_facebook = session ? true : false;

          // if the new state is the same as the old (i.e., nothing changed)
          // then do nothing
          if (is_now_logged_into_facebook == already_logged_into_facebook) {
            return;
          }

          // otherwise, refresh to pick up the state change
          refresh_page();
        });
    });
}

/*
 * Our <fb:login-button> specifies this function in its onlogin attribute,
 * which is triggered after the user authenticates the app in the Connect
 * dialog and the Facebook session has been set in the cookies.
 */
function facebook_onlogin_ready() {
  // In this app, we redirect the user back to index.php. The server will read
  // the cookie and see that the user is logged in, and will deliver a new page
  // with content appropriate for a logged-in user.
  //
  // However, a more complex app could use this function to do AJAX calls
  // and/or in-place replacement of page contents to avoid a full page refresh.
  refresh_page(true);
}

/*
 * Do a page refresh after login state changes.
 */
function refresh_page(button_clicked) {
    if (button_clicked) {
        var url = String(window.location);
        
        if ('/' != url[url.length-1]) {
            url += '/';
        }

        if (url.indexOf('?') < 0) {
            url += '?';
        } else {
            url += '&';
        }

        url += 'button_clicked=1'; 

        window.location = url;
    } else {
       window.location.reload();
    }
}