/**
* Date/time formatter
*
* Converts a date, specified in $input_format format, in the $format
* format and returns the result. If $input is not defined, the current
* time is used as input.
*
* The $format parameter can be one of the following values:
* - 'date' for a string with a date description (current locale)
* - 'date_sql' for date in common SQL format ('%Y-%m-%d')
* - 'date_iso8601' same as 'date_sql'
* - 'datetime' for a string with date and time description (current locale)
* - 'datetime_sql' for a string with a time description as '%Y-%m-%d %H:%M:%S'
* - 'datetime_iso8601' for a string with time description in ISO 8601 format
* - 'datetime_rfc3339' for a string as described in RFC3339 (atom format)
*
* Any other value will be passed directly to strftime().
*
* The $input_format parameter can be one of the following values:
* - 'timestamp' for UNIX timestamps
* - 'sql' for common SQL date/datetime
*
* @param string $format The format of the resulting date
* @param mixed $input The source date to format
* @param string $input_format The format of the source date
* @return mixed|null The formatted date or null on errors
*/
public static function formatDate($format, $input = null, $input_format = 'timestamp')
{
if (is_null($input)) {
$timestamp = time();
} elseif ($input_format == 'timestamp') {
$timestamp = $input;
} else {
$timestamp = TIP::getTimestamp($input, $input_format);
}
return empty($timestamp) ? null : TIP::_formatTimestamp($timestamp, $format);
}
