application/TimeZone.php

   1 <?php
   2
   3 /**
   4  * Generates a list of available timezone continents and cities.
   5  *
   6  * Two distinct array based on available timezones
   7  * and the one selected in the settings:
   8  *   - (0) continents:
   9  *     + list of available continents
  10  *     + special key 'selected' containing the value of the selected timezone's continent
  11  *   - (1) cities:
  12  *     + list of available cities associated with their continent
  13  *     + special key 'selected' containing the value of the selected timezone's city (without the continent)
  14  *
  15  * Example:
  16  *   [
  17  *     [
  18  *       'America',
  19  *       'Europe',
  20  *       'selected' => 'Europe',
  21  *     ],
  22  *     [
  23  *       ['continent' => 'America', 'city' => 'Toronto'],
  24  *       ['continent' => 'Europe', 'city' => 'Paris'],
  25  *       'selected' => 'Paris',
  26  *     ],
  27  *   ];
  28  *
  29  * Notes:
  30  *   - 'UTC/UTC' is mapped to 'UTC' to form a valid option
  31  *   - a few timezone cities includes the country/state, such as Argentina/Buenos_Aires
  32  *   - these arrays are designed to build timezone selects in template files with any HTML structure
  33  *
  34  * @param array  $installedTimeZones  List of installed timezones as string
  35  * @param string $preselectedTimezone preselected timezone (optional)
  36  *
  37  * @return array[] continents and cities
  38  **/
  39 function generateTimeZoneData($installedTimeZones, $preselectedTimezone = '')
  40 {
  41     if ($preselectedTimezone == 'UTC') {
  42         $pcity = $pcontinent = 'UTC';
  43     } else {
  44         // Try to split the provided timezone
  45         $spos = strpos($preselectedTimezone, '/');
  46         $pcontinent = substr($preselectedTimezone, 0, $spos);
  47         $pcity = substr($preselectedTimezone, $spos + 1);
  48     }
  49
  50     $continents = [];
  51     $cities = [];
  52     foreach ($installedTimeZones as $tz) {
  53         if ($tz == 'UTC') {
  54             $tz = 'UTC/UTC';
  55         }
  56         $spos = strpos($tz, '/');
  57
  58         // Ignore invalid timezones
  59         if ($spos === false) {
  60             continue;
  61         }
  62
  63         $continent = substr($tz, 0, $spos);
  64         $city = substr($tz, $spos + 1);
  65         $cities[] = ['continent' => $continent, 'city' => $city];
  66         $continents[$continent] = true;
  67     }
  68
  69     $continents = array_keys($continents);
  70     $continents['selected'] = $pcontinent;
  71     $cities['selected'] = $pcity;
  72
  73     return [$continents, $cities];
  74 }
  75
  76 /**
  77  * Tells if a continent/city pair form a valid timezone
  78  *
  79  * Note: 'UTC/UTC' is mapped to 'UTC'
  80  *
  81  * @param string $continent the timezone continent
  82  * @param string $city      the timezone city
  83  *
  84  * @return bool whether continent/city is a valid timezone
  85  */
  86 function isTimeZoneValid($continent, $city)
  87 {
  88     return in_array(
  89         $continent . '/' . $city,
  90         timezone_identifiers_list()
  91     );
  92 }