Silly question. But I cant get the result I want.

I have a Interval field which is calculated (for a single record) in JS which can house values of '32:00:00'

But now I need to subtract eg. '04:00:00' from that, but its done in PHP in the back end.

But it seems to stop at '23:59:59'. I know its because its a full day.

Is there a way to calculate the interval to show something like '32:00:00'

        $readyDate = substr($pat['ready4disch_date'],0,10);
        $readyTime = ($pat['ready4disch_time'] != null) ? $pat['ready4disch_time'] : '00:00:00';
        $disDate = substr($pat['date_unit_discharge'],0,10);
        $disTime = ($pat['time_unit_discharge'] != null) ? $pat['time_unit_discharge'] : '00:00:00';

        $ready      = new Carbon($readyDate.' '.$readyTime);
        $discharge  = new Carbon($disDate.' '.$disTime);


        //Calculate difference between decision and admission
        $min = $ready->diff($discharge);
        $admSec = date_create('@0')->add($min)->getTimestamp();

        //Convert Margin to usable time
        $marSec = strtotime($margin) - strtotime('TODAY'); // 3600

        //Subtract margin from delay
        $result = $admSec - $marSec;
        $result = ($result > 0 ) ? $this->secondsToTime($result) : $this->secondsToTime(0);

CodePudding user response：

The trouble is that you're trying to trick a date library into doing basic interval math, and it doesn't like trying to interpret times later than 23:59:59 because it will either consider them impossible, or edge case misrepresentations of data reinterpreted to "the next day".

Rather than trying to force this fish to ride a bicycle I'd say it's more productive to whip up something that does the relatively simple thing that you actually want to do.

class SimpleInterval {
    protected $seconds;
    protected static $conv = [1, 60, 60];
    
    public function __construct(int $seconds) {
        $this->seconds = $seconds;
    }
    
    public static function fromString(string $interval) {
        $seconds = 0;
        $mul = 1;
        $parts = array_reverse(explode(":", $interval));
        $c=count($parts);
        
        if( $c > count(self::$conv) ) {
            throw new \Exception('Supplied interval string has more components than I know how to convert.');
        }
        
        for( $i=0; $i<$c;   $i ) {
            $mul *= self::$conv[$i];
            $seconds  = $parts[$i] * $mul;
        }
        return new self($seconds);
    }
    
    public function getSeconds() {
        return $this->seconds;
    }
    
    public function subtract(SimpleInterval $i) {
        return new self($this->seconds - $i->getSeconds());
    }
    
    public function __toString() {
        $res=[];
        $time = $this->seconds;
        $mul = 1;
        for( $i=1, $c=count(self::$conv); $i<$c;   $i ) {
            $mul = self::$conv[$i];
            $cur = $time % $mul;
            $res[] = $cur;
            $time = ($time - $cur) / $mul;
        }
        $res[] = $time;
        return implode(':', array_map(
            function($a){return sprintf('d', $a);},
            array_reverse($res)
        ));
    }
    
    public function asDateInterval() {
        return new DateInterval(sprintf('PT%dS', $this->seconds));
    }
}

$a = '32:00:00';
$b = '4:00:00';

var_dump(
    $c = SimpleInterval::fromString($a)->subtract(SimpleInterval::fromString($b)),
    (string)$c,
    $c->asDateInterval()
);

Output:

object(SimpleInterval)#3 (1) {
  ["seconds":protected]=>
  int(100800)
}

string(8) "28:00:00"

object(DateInterval)#1 (16) {
  ["y"]=>
  int(0)
  ["m"]=>
  int(0)
  ["d"]=>
  int(0)
  ["h"]=>
  int(0)
  ["i"]=>
  int(0)
  ["s"]=>
  int(100800)
  ["f"]=>
  float(0)
  ["weekday"]=>
  int(0)
  ["weekday_behavior"]=>
  int(0)
  ["first_last_day_of"]=>
  int(0)
  ["invert"]=>
  int(0)
  ["days"]=>
  bool(false)
  ["special_type"]=>
  int(0)
  ["special_amount"]=>
  int(0)
  ["have_weekday_relative"]=>
  int(0)
  ["have_special_relative"]=>
  int(0)
}