<?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]); 
    } 
} 
?>