Calculating shift hours worked and detecting - php

Question

I have a problem. My English is pretty bad. I need to do an overtime calculation with PHP. There is already a code for this. But when the working time is more than 2 days, the calculation is wrong.
Working Start: 2018-09-09 13:43
Working End: 2018-09-11 07:13
Result: 07:18 | 04:00 | 04:00 | 02:00 | 17:18
I can't figure out the problem, please help.
I'd like to give you more details, but I'm pretty bad. I hope you understand me.
Thanks.
<?php
function intersection($s1, $e1, $s2, $e2,$day) {
return subintersection($s1,$e1,$s2,$e2)+subintersection($s1,$e1,$s2+$day,$e2+$day);
}
function subintersection($s1, $e1, $s2, $e2) {
if ($e1 < $s2)
return 0;
if ($s1 > $e2)
return 0;
if ($s1 < $s2)
$s1 = $s2;
if ($e1 > $e2)
$e1 = $e2;
return $e1 - $s1;
}
function minuteToHours($time, $format = '%02d:%02d') {
if ($time < 1) {
return;
}
$hours = floor($time / 60);
$minutes = ($time % 60);
return sprintf($format, $hours, $minutes);
}
function calculateWork($strstart, $strend, $arg = NULL){
$day= 3600*24;
$strS = strtotime($strstart);
$strE = strtotime($strend);
$date_start = date('Y-m-d', $strS);
$date_end = date('Y-m-d', $strE);
$hour_start = date('H:i', $strS);
$hour_end = date('H:i', $strE);
$start = strtotime($hour_start);
$end = strtotime($hour_end);
if($date_start != $date_end){
$end = $end + 3600*24;
}
$tip1_start = strtotime("06:00");
$tip1_end = strtotime("20:00");
$tip2_start = strtotime("20:00");
$tip2_end = strtotime("00:00") + 3600*24;
$tip3_start = strtotime("00:00");
$tip3_end = strtotime("04:00");
$tip4_start = strtotime("04:00");
$tip4_end = strtotime("06:00");
$tip1 = intersection( $start, $end, $tip1_start, $tip1_end, $day) / 60;
$tip2 = intersection( $start, $end, $tip2_start, $tip2_end, $day) / 60;
$tip3 = intersection( $start, $end, $tip3_start, $tip3_end, $day) / 60;
$tip4 = intersection( $start, $end, $tip4_start, $tip4_end, $day) / 60;
if(null !== minuteToHours($tip1, '%02d:%02d')){
$t1 = minuteToHours($tip1, '%02d:%02d');
}
if(null !== minuteToHours($tip2, '%02d:%02d')){
$t2 = minuteToHours($tip2, '%02d:%02d');
}
if(null !== minuteToHours($tip3, '%02d:%02d')){
$t3 = minuteToHours($tip3, '%02d:%02d');
}
if(null !== minuteToHours($tip4, '%02d:%02d')){
$t4 = minuteToHours($tip4, '%02d:%02d');
}
$topla = $tip1 + $tip2 + $tip3 + $tip4;
$total = minuteToHours($topla, '%02d:%02d');
return "{$t1}|{$t2}|{$t3}|{$t4}|{$total}";
}
echo calculateWork("2018-09-09 13:43", "2018-09-11 07:01");
//07:18|04:00|04:00|02:00|17:18