Calculation of interval duration

Question

Good morning, I would like to know that someone can help me create an interface in conjunction with the calculation, in PHP, between hours of work with minutes of pause. That is, we would have an input time entered by the user and an output time. In a separate input a pause hours/minutes input.

I have seriously tried to make the necessary calculations to give correctly, but the hours and minutes minus the break, have gone wrong.

I leave here a little of the code I have made.

<input type="text" name="horai" id="horai" style="border: 1px solid #ccc; border-radius: 4px; padding: 6px;" required/> 
<input type="text" name="horaf" id="horaf" style="border: 1px solid #ccc; border-radius: 4px; padding: 6px;" required/>

<?php

if($_POST['horai'] > $_POST['horaf']){
    $total = (24 - $_POST['horai'] + $_POST['horaf']);
}else{
    $total = $_POST['horaf'] - $_POST['horai'];
}

$iTime= strtotime($_POST['horai']);
$fTime= strtotime($_POST['horaf']);

if($fTime> $iTime){
    $diferenca = $fTime- $iTime; 
    $semintervalo = date('H:i', $diferenca); 
} else {
    $diferenca = (24 - $iTime) + $fTime;
    $semintervalo = date('H:i', $diferenca);
}

$tempodepausa= strtotime($_POST['pausa']);
$tempodepausaaux= $diferenca- $semintervalo;
$comintervalo = date('H:i', $tempodepausaaux);

echo 'Diferença entre Horas (s): '.$diferenca.'<br/>';
echo 'Diferença entre Horas (H:m): '.$semintervalo.'<br/>';
echo 'Tempo útil (H:m): '.$comintervalo.'<br/>';
echo 'Tempo útil (s): '.$tempodepausaaux;

?>

Answer 1

I did it this way:

// cada servidor tem timezone diferente
// para corrigir isso, basta adicionar a linha abaixo que ficará padrão
// explicarei melhor no edit 

date_default_timezone_set('UTC'); 

$iTime= strtotime($_POST['horai']);
$fTime= strtotime($_POST['horaf']);

$tempopausaINI = strtotime("00:00:00");
$tempodepausa = strtotime($_POST['pausa']);
$tempoPausaTotal = abs($tempopausaINI - $tempodepausa);

// esse if apenas assegura que os valores formam convertidos
if ($tempodepausa !== false && $iTime !== false && $fTime !== false) {
    if($fTime > $iTime){
        $diferenca = ($fTime - $iTime); 
    } else {
        $diferenca = abs($iTime - $fTime); // o abs coloca o valor para positivo
    }
    $semintervalo = date('H:i:s', $diferenca);
    $tempodepausaaux = $diferenca - $tempoPausaTotal;
    $comintervalo = date('H:i:s', $tempodepausaaux);

    echo 'Diferença entre Horas (s): '.strtotime('1970-01-01 '.$semintervalo .'UTC').'<br/>';
    echo 'Diferença entre Horas (H:m): '.$semintervalo.'<br/>';
    echo 'Tempo útil (H:m): '.$comintervalo.'<br/>';
    echo 'Tempo útil (s): '.strtotime('1970-01-01 '.$comintervalo .'UTC');
}

The problems I identified:

1) In this row below, you try to subtract a timestamp from a date. It will not work:

$tempodepausaaux= $diferenca- $semintervalo;

2) Each time in timestamp has a value of 3600 integer. In the row below you subtract the number 24 from the initial time, which will only make it negative with a wrong value difference.

$diferenca = (24 - $iTime) + $fTime;

3) This condition is useless, you may have used it for testing:

if($_POST['horai'] > $_POST['horaf']){
    $total = (24 - $_POST['horai'] + $_POST['horaf']);
}else{
    $total = $_POST['horaf'] - $_POST['horai'];
}

4) Another problem is the pause time. When you turn the hour/minute time into timestamp without putting an initial value to compare. This comparison is made on the initial date of "1970-01-01". So I changed the value of:

$tempodepausa= strtotime($_POST['pausa']);

To:

$tempopausaINI = strtotime("00:00:00");
$tempodepausa = strtotime($_POST['pausa']);
$tempoPausaTotal = abs($tempopausaINI - $tempodepausa);

Thus, you will have the correct value in pause timestamp.

Anyway, his logic was correct, only a few details were wrong.

EDIT

The strtotime by default it returns in seconds the start date January 1 1970 00:00:00 GMT until the stipulated date. However, each server can be configured with a different time zone. If you convert this value into timestamp for the date() without changing the time zone, the date / time can be changed. For if in timestamp the start date is on January 1 at 00 o'clock GMT, for other servers this start can start later by changing the expected value.

There’s a change in this if also:

if($fTime > $iTime){
    $diferenca = ($fTime - $iTime); 
} else {
    $diferenca = abs($iTime - $fTime); // o abs coloca o valor para positivo
}