application/TimeZone.php

   1 <?php
   2 /**
   3  * Generates the timezone selection form and JavaScript.
   4  *
   5  * Note: 'UTC/UTC' is mapped to 'UTC' to form a valid option
   6  *
   7  * Example: preselect Europe/Paris
   8  *  list($htmlform, $js) = templateTZform('Europe/Paris');
   9  *
  10  * @param string $preselected_timezone preselected timezone (optional)
  11  *
  12  * @return an array containing the generated HTML form and Javascript code
  13  **/
  14 function generateTimeZoneForm($preselected_timezone='')
  15 {
  16     // Select the first available timezone if no preselected value is passed
  17     if ($preselected_timezone == '') {
  18         $l = timezone_identifiers_list();
  19         $preselected_timezone = $l[0];
  20     }
  21
  22     // Try to split the provided timezone
  23     $spos = strpos($preselected_timezone, '/');
  24     $pcontinent = substr($preselected_timezone, 0, $spos);
  25     $pcity = substr($preselected_timezone, $spos+1);
  26
  27     // Display config form:
  28     $timezone_form = '';
  29     $timezone_js = '';
  30
  31     // The list is in the form 'Europe/Paris', 'America/Argentina/Buenos_Aires'...
  32     // We split the list in continents/cities.
  33     $continents = array();
  34     $cities = array();
  35
  36     // TODO: use a template to generate the HTML/Javascript form
  37
  38     foreach (timezone_identifiers_list() as $tz) {
  39         if ($tz == 'UTC') {
  40             $tz = 'UTC/UTC';
  41         }
  42         $spos = strpos($tz, '/');
  43
  44         if ($spos !== false) {
  45             $continent = substr($tz, 0, $spos);
  46             $city = substr($tz, $spos+1);
  47             $continents[$continent] = 1;
  48
  49             if (!isset($cities[$continent])) {
  50                 $cities[$continent] = '';
  51             }
  52             $cities[$continent] .= '<option value="'.$city.'"';
  53             if ($pcity == $city) {
  54                 $cities[$continent] .= ' selected="selected"';
  55             }
  56             $cities[$continent] .= '>'.$city.'</option>';
  57         }
  58     }
  59
  60     $continents_html = '';
  61     $continents = array_keys($continents);
  62
  63     foreach ($continents as $continent) {
  64         $continents_html .= '<option  value="'.$continent.'"';
  65         if ($pcontinent == $continent) {
  66             $continents_html .= ' selected="selected"';
  67         }
  68         $continents_html .= '>'.$continent.'</option>';
  69     }
  70
  71     // Timezone selection form
  72     $timezone_form = 'Continent:';
  73     $timezone_form .= '<select name="continent" id="continent" onChange="onChangecontinent();">';
  74     $timezone_form .= $continents_html.'</select>';
  75     $timezone_form .= '&nbsp;&nbsp;&nbsp;&nbsp;City:';
  76     $timezone_form .= '<select name="city" id="city">'.$cities[$pcontinent].'</select><br />';
  77
  78     // Javascript handler - updates the city list when the user selects a continent
  79     $timezone_js = '<script>';
  80     $timezone_js .= 'function onChangecontinent() {';
  81     $timezone_js .= 'document.getElementById("city").innerHTML =';
  82     $timezone_js .= ' citiescontinent[document.getElementById("continent").value]; }';
  83     $timezone_js .= 'var citiescontinent = '.json_encode($cities).';';
  84     $timezone_js .= '</script>';
  85
  86     return array($timezone_form, $timezone_js);
  87 }
  88
  89 /**
  90  * Tells if a continent/city pair form a valid timezone
  91  *
  92  * Note: 'UTC/UTC' is mapped to 'UTC'
  93  *
  94  * @param string $continent the timezone continent
  95  * @param string $city      the timezone city
  96  *
  97  * @return whether continent/city is a valid timezone
  98  */
  99 function isTimeZoneValid($continent, $city)
 100 {
 101     if ($continent == 'UTC' && $city == 'UTC') {
 102         return true;
 103     }
 104
 105     return in_array(
 106         $continent.'/'.$city,
 107         timezone_identifiers_list()
 108     );
 109 }
 110 ?>