<?php

App::uses('AppHelper','View/Helper');

class TimeZoneHelper extends AppHelper {

    public $helpers = array('Form');

    function generateList() {

        $list = DateTimeZone::listAbbreviations();
        $idents = DateTimeZone::listIdentifiers();

        $data = $offset = $added = array();
        foreach ($list as $abbr => $info) {
            foreach ($info as $zone) {
                if ( ! empty($zone['timezone_id'])
                    AND
                    ! in_array($zone['timezone_id'], $added)
                    AND
                      in_array($zone['timezone_id'], $idents)) {
                    $z = new DateTimeZone($zone['timezone_id']);
                    $c = new DateTime(null, $z);
                    $zone['time'] = $c->format('H:i a');
                    $data[] = $zone;
                    $offset[] = $z->getOffset($c);
                    $added[] = $zone['timezone_id'];
                }
            }
        }

        array_multisort($offset, SORT_ASC, $data);
        $options = array();
        foreach ($data as $key => $row) {
            $options[$row['timezone_id']] = $row['time'] . ' - '
                                            . $this->formatOffset($row['offset'])
                                            . ' ' . $row['timezone_id'];
        }

        return $options;

    }

    function formatOffset($offset) {
            $hours = $offset / 3600;
            $remainder = $offset % 3600;
            $sign = $hours > 0 ? '+' : '-';
            $hour = (int) abs($hours);
            $minutes = (int) abs($remainder / 60);

            if ($hour == 0 AND $minutes == 0) {
                $sign = ' ';
            }
            return 'GMT' . $sign . str_pad($hour, 2, '0', STR_PAD_LEFT)
                    .':'. str_pad($minutes,2, '0');

    }

    function select($fieldname, $label="Please Choose a timezone") {

        $list = $this->Form->input($fieldname, array("type"=>"select", "label"=>$label, "options"=>$this->generateList(), "error"=>"Please choose a timezone"));
        return $this->output($list);
    }

    function display($index) {
        return $this->output($this->timezones[$index]);
    }
}
?>