application/TimeZone.php

   1 <?php
   2 /**
   3  * Generates a list of available timezone continents and cities.
   4  *
   5  * Two distinct array based on available timezones
   6  * and the one selected in the settings:
   7  *   - (0) continents:
   8  *     + list of available continents
   9  *     + special key 'selected' containing the value of the selected timezone's continent
  10  *   - (1) cities:
  11  *     + list of available cities associated with their continent
  12  *     + special key 'selected' containing the value of the selected timezone's city (without the continent)
  13  *
  14  * Example:
  15  *   [
  16  *     [
  17  *       'America',
  18  *       'Europe',
  19  *       'selected' => 'Europe',
  20  *     ],
  21  *     [
  22  *       ['continent' => 'America', 'city' => 'Toronto'],
  23  *       ['continent' => 'Europe', 'city' => 'Paris'],
  24  *       'selected' => 'Paris',
  25  *     ],
  26  *   ];
  27  *
  28  * Notes:
  29  *   - 'UTC/UTC' is mapped to 'UTC' to form a valid option
  30  *   - a few timezone cities includes the country/state, such as Argentina/Buenos_Aires
  31  *   - these arrays are designed to build timezone selects in template files with any HTML structure
  32  *
  33  * @param array  $installedTimeZones  List of installed timezones as string
  34  * @param string $preselectedTimezone preselected timezone (optional)
  35  *
  36  * @return array[] continents and cities
  37  **/
  38 function generateTimeZoneData($installedTimeZones, $preselectedTimezone = '')
  39 {
  40     if ($preselectedTimezone == 'UTC') {
  41         $pcity = $pcontinent = 'UTC';
  42     } else {
  43         // Try to split the provided timezone
  44         $spos = strpos($preselectedTimezone, '/');
  45         $pcontinent = substr($preselectedTimezone, 0, $spos);
  46         $pcity = substr($preselectedTimezone, $spos+1);
  47     }
  48
  49     $continents = [];
  50     $cities = [];
  51     foreach ($installedTimeZones as $tz) {
  52         if ($tz == 'UTC') {
  53             $tz = 'UTC/UTC';
  54         }
  55         $spos = strpos($tz, '/');
  56
  57         // Ignore invalid timezones
  58         if ($spos === false) {
  59             continue;
  60         }
  61
  62         $continent = substr($tz, 0, $spos);
  63         $city = substr($tz, $spos+1);
  64         $cities[] = ['continent' => $continent, 'city' => $city];
  65         $continents[$continent] = true;
  66     }
  67
  68     $continents = array_keys($continents);
  69     $continents['selected'] = $pcontinent;
  70     $cities['selected'] = $pcity;
  71
  72     return [$continents, $cities];
  73 }
  74
  75 /**
  76  * Tells if a continent/city pair form a valid timezone
  77  *
  78  * Note: 'UTC/UTC' is mapped to 'UTC'
  79  *
  80  * @param string $continent the timezone continent
  81  * @param string $city      the timezone city
  82  *
  83  * @return bool whether continent/city is a valid timezone
  84  */
  85 function isTimeZoneValid($continent, $city)
  86 {
  87     return in_array(
  88         $continent.'/'.$city,
  89         timezone_identifiers_list()
  90     );
  91 }