Convert NBA API clock timestamp format

pt_time_format.php

<?php
$sample1 = "PT12M00.00S";
$sample2 = "PT01M05S";
$sample3 = "PT00M05.30S";
$sample4 = "PT00M00.00S";

function PTFormatAsArray(string $timestamp): array
{
    if (str_contains($timestamp, ".")) {
        $after_dot = substr($timestamp, strpos($timestamp, ".") + 1);
        $milliseconds = str_replace("S", "", $after_dot);
        $timestamp = str_replace(".{$milliseconds}", "", $timestamp);
    } else {
        $milliseconds = '00';
    }
    $d = new DateInterval($timestamp);
    return array(
        'H' => $d->format('%H'),
        'i' => $d->format('%I'),
        's' => $d->format('%S'),
        'u' => $milliseconds
    );
}

function PTFormatAsString(string $timestamp): string
{
    if (str_contains($timestamp, ".")) {
        $after_dot = substr($timestamp, strpos($timestamp, ".") + 1);
        $milliseconds = str_replace("S", "", $after_dot);
        $timestamp = str_replace(".{$milliseconds}", "", $timestamp);
    } else {
        $milliseconds = '00';
    }
    $d = new DateInterval($timestamp);
    return "{$d->format('%H')}:{$d->format('%I')}:{$d->format('%S')}.{$milliseconds}";
}


function PTFormatAsSeconds(string $timestamp): int
{
    if (str_contains($timestamp, ".")) {
        $after_dot = substr($timestamp, strpos($timestamp, ".") + 1);
        $milliseconds = str_replace("S", "", $after_dot);
        $timestamp = str_replace(".{$milliseconds}", "", $timestamp);
    }
    $d = new DateInterval($timestamp);
    return (int)$d->format('%i') * 60 + (int)$d->format('%s');
}