Check if time interval does fall inside other time intervals - php

Question

I want to determine if given interval doesn't fall inside other intervals (using 24-hour clock format), here is the example:
case1:
$startDate = '2021-04-05 08:05:00';
$endDate = '2021-04-05 10:05:00';
$intervals = [['startDate' => '2021-04-05 08:30:00', 'endDate' => '2021-04-05 11:05:00'], ['startDate' => '2021-04-05 12:30:00', 'endDate' => '2021-04-05 13:05:00']]
In this case we should set:
$flagCanSchedule = 0;
Because 2021-04-05 08:05:00 to 2021-04-05 10:05:00 falls between this interval:
'startDate' => '2021-04-05 08:30:00', 'endDate' => '2021-04-05
11:05:00'
But for this:
case 2:
$startDate = '2021-04-05 08:05:00';
$endDate = '2021-04-05 10:05:00';
$intervals = [['startDate' => '2021-04-05 10:05:00', 'endDate' => '2021-04-05 11:05:00'], ['startDate' => '2021-04-05 07:30:00', 'endDate' => '2021-04-05 08:05:00']]
In this case set:
$flagCanSchedule = 1;
Because we don't overlap any other interval, evan tho ('2021-04-05 08:05:00' == '2021-04-05 08:05:00').
I wanted to solve this using strtotime and transform the dates to unix format, but I'm not sure how to write my if statement.
$startDate = strtotime('2021-04-05 08:05:00');
$endDate = strtotime('2021-04-05 10:05:00');
foreach($intervals as $interval) {
if($startDate <= strtotime($interval['startDate']) && $endDate <=
strtotime($interval['endDate'])) {
$flagCanSchedule = 1;
} else {
$flagCanSchedule = 0;
}
}

Answer 1

You should add a break when a flagCanSchedule is found. Because, the next iterations overrides this value (from 1 to 0).
$intervals = [
['startDate' => '2021-04-05 10:05:00', 'endDate' => '2021-04-05 11:05:00'],
['startDate' => '2021-04-05 07:30:00', 'endDate' => '2021-04-05 08:05:00'],
];
$startDate = strtotime('2021-04-05 08:05:00');
$endDate = strtotime('2021-04-05 10:05:00');
foreach($intervals as $interval)
{
if ($startDate <= strtotime($interval['startDate']) &&
$endDate <= strtotime($interval['endDate']))
{
$flagCanSchedule = 1;
break; // << stop the test
}
else {
$flagCanSchedule = 0;
}
}
var_dump($flagCanSchedule); // int(1)
You also can remove the else statement by initializing the flag first.
$flagCanSchedule = 0;
foreach ($intervals as $interval)
{
if ($startDate <= strtotime($interval['startDate']) &&
$endDate <= strtotime($interval['endDate']))
{
$flagCanSchedule = 1;
break;
}
}
var_dump($flagCanSchedule); // int(1)