--- /dev/null
+<?php
+
+/**
+ * @file src/Util/DateTimeFormat.php
+ */
+
+namespace Friendica\Util;
+
+use DateTime;
+use DateTimeZone;
+use Exception;
+
+/**
+ * @brief Temporal class
+ */
+class DateTimeFormat
+{
+ const ATOM = 'Y-m-d\TH:i:s\Z';
+ const MYSQL = 'Y-m-d H:i:s';
+
+ /**
+ * convert() shorthand for UTC.
+ *
+ * @param string $time A date/time string
+ * @param string $format DateTime format string or Temporal constant
+ * @return string
+ */
+ public static function utc($time, $format = self::MYSQL)
+ {
+ return self::convert($time, 'UTC', 'UTC', $format);
+ }
+
+ /**
+ * convert() shorthand for local.
+ *
+ * @param string $time A date/time string
+ * @param string $format DateTime format string or Temporal constant
+ * @return string
+ */
+ public static function local($time, $format = self::MYSQL)
+ {
+ return self::convert($time, date_default_timezone_get(), 'UTC', $format);
+ }
+
+ /**
+ * convert() shorthand for timezoned now.
+ *
+ * @param string $format DateTime format string or Temporal constant
+ * @return string
+ */
+ public static function timezoneNow($timezone, $format = self::MYSQL)
+ {
+ return self::convert('now', $timezone, 'UTC', $format);
+ }
+
+ /**
+ * convert() shorthand for local now.
+ *
+ * @param string $format DateTime format string or Temporal constant
+ * @return string
+ */
+ public static function localNow($format = self::MYSQL)
+ {
+ return self::local('now', $format);
+ }
+
+ /**
+ * convert() shorthand for UTC now.
+ *
+ * @param string $format DateTime format string or Temporal constant
+ * @return string
+ */
+ public static function utcNow($format = self::MYSQL)
+ {
+ return self::utc('now', $format);
+ }
+
+ /**
+ * @brief General purpose date parse/convert/format function.
+ *
+ * @param string $s Some parseable date/time string
+ * @param string $tz_to Destination timezone
+ * @param string $tz_from Source timezone
+ * @param string $format Output format recognised from php's DateTime class
+ * http://www.php.net/manual/en/datetime.format.php
+ *
+ * @return string Formatted date according to given format
+ */
+ public static function convert($s = 'now', $tz_to = 'UTC', $tz_from = 'UTC', $format = self::MYSQL)
+ {
+ // Defaults to UTC if nothing is set, but throws an exception if set to empty string.
+ // Provide some sane defaults regardless.
+ if ($from === '') {
+ $from = 'UTC';
+ }
+
+ if ($to === '') {
+ $to = 'UTC';
+ }
+
+ if (($s === '') || (!is_string($s))) {
+ $s = 'now';
+ }
+
+ /*
+ * Slight hackish adjustment so that 'zero' datetime actually returns what is intended
+ * otherwise we end up with -0001-11-30 ...
+ * add 32 days so that we at least get year 00, and then hack around the fact that
+ * months and days always start with 1.
+ */
+ if (substr($s, 0, 10) <= '0001-01-01') {
+ $d = new DateTime($s . ' + 32 days', new DateTimeZone('UTC'));
+ return str_replace('1', '0', $d->format($format));
+ }
+
+ try {
+ $from_obj = new DateTimeZone($tz_from);
+ } catch (Exception $e) {
+ $from_obj = new DateTimeZone('UTC');
+ }
+
+ try {
+ $d = new DateTime($s, $from_obj);
+ } catch (Exception $e) {
+ logger('datetime_convert: exception: ' . $e->getMessage());
+ $d = new DateTime('now', $from_obj);
+ }
+
+ try {
+ $to_obj = new DateTimeZone($tz_to);
+ } catch (Exception $e) {
+ $to_obj = new DateTimeZone('UTC');
+ }
+
+ $d->setTimeZone($to_obj);
+
+ return $d->format($format);
+ }
+}