public static function ageByYear($year, $month = null)
{
if ($month === null) {
$maxAge = static::age(mktime(0, 0, 0, 1, 1, $year));
$minAge = static::age(mktime(23, 59, 59, 12, 31, $year));
$ages = array_unique([$minAge, $maxAge]);
return implode('/', $ages);
}
if (date('n') == $month) {
$maxAge = static::age(mktime(0, 0, 0, $month, 1, $year));
$minAge = static::age(mktime(23, 59, 59, $month, static::daysInMonth($year, $month), $year));
$ages = array_unique([$minAge, $maxAge]);
return implode('/', $ages);
}
return static::age(mktime(0, 0, 0, $month, 1, $year));
}