public static function getTotalXpRequirement(int $level) : int
{
if ($level <= 16) {
return $level ** 2 + 6 * $level;
} elseif ($level <= 31) {
return 2.5 * $level ** 2 - 40.5 * $level + 360;
} elseif ($level <= 21863) {
return 4.5 * $level ** 2 - 162.5 * $level + 2220;
}
return PHP_INT_MAX;
//prevent float returns for invalid levels on 32-bit systems
}