/**
* Builds a XMLElement containing a `<select>` with all the available timezone
* options grouped by the different DateTimeZone constants allowed by an instance
* of this field. Developers can select what Timezones are available from the
* Section Editor.
*
* @link http://www.php.net/manual/en/class.datetimezone.php
* @param array $data
* @param string $prefix
* @param string $postfix
* @return XMLElement
*/
public function buildTZSelection($data = array(), $prefix = null, $postfix = null)
{
if (is_null($data)) {
$data = array();
}
$groups = array();
if ($this->get('required') != 'yes') {
$groups[] = array(NULL, false, NULL);
}
$zones = explode(",", $this->get('available_zones'));
foreach ($zones as $zone) {
$timezones = DateTimeObj::getTimezones($zone);
$options = array();
foreach ($timezones as $timezone) {
$tz = new DateTime('now', new DateTimeZone($timezone));
$options[] = array($timezone, $timezone == $data['value'], sprintf("%s %s", str_replace('_', ' ', substr(strrchr($timezone, '/'), 1)), $tz->format('P')));
}
$groups[] = array('label' => ucwords(strtolower($zone)), 'options' => $options);
}
$label = new XMLElement('label', $this->get('label'));
$label->appendChild(Widget::Select("fields{$prefix}[{$this->get('element_name')}]{$postfix}", $groups));
return $label;
}
