I’m working on a PHP project where I need to calculate the opening times for a business, which includes both regular weekly schedules and special non-standard times for holidays. I have two arrays: one for the regular schedule and another for the non-standard times.

Regular opening times array:

$opening_times = [
    ['open' => '09:00:00', 'weekday' => 1], // Monday
    ['open' => '09:00:00', 'weekday' => 2], // Tuesday
    ['open' => '09:00:00', 'weekday' => 4], // Thursday, Wednesday is closed
    ['open' => '09:00:00', 'weekday' => 5], // Friday opening time 1
    ['open' => '16:00:00', 'weekday' => 5], // Friday opening time 2
    ['open' => '09:00:00', 'weekday' => 6], // Saturday
    ['open' => '09:00:00', 'weekday' => 7], // Sunday
];

Non-standard opening times array (for holidays etc.):

$special_opening_times = [
    ['date' => '2024-04-24', 'open' => '08:00:00'],
    ['date' => '2024-04-27', 'open' => '08:00:00'],
    ['date' => '2024-04-28', 'open' => '09:00:00'],
    ['date' => '2024-04-30', 'open' => '07:00:00'],
    ['date' => '2024-04-25', 'open' => '11:00:00']
];

Using some inspiration from this question I was able to craft this for the non-standard opening times array:

// Your reference datetime
$reference_datetime = '2024-04-25 10:30:00';

// Array with dates and times
$special_opening_times = [
    ['date' => '2024-04-24', 'open' => '08:00:00'],
    ['date' => '2024-04-27', 'open' => '08:00:00'],
    ['date' => '2024-04-28', 'open' => '09:00:00'],
    ['date' => '2024-04-30', 'open' => '07:00:00'],
    ['date' => '2024-04-25', 'open' => '11:00:00'] // Same day, later time
];

// Function to sort datetimes
function datetime_sort($a, $b) {
    $a_datetime = strtotime($a['date'] . ' ' . $a['open']);
    $b_datetime = strtotime($b['date'] . ' ' . $b['open']);
    return $a_datetime - $b_datetime;
}

// Sort datetimes using the custom function
usort($special_opening_times, 'datetime_sort');

// Variable to hold the next closest datetime
$next_datetime = null;

// Loop through sorted datetimes and find the next closest datetime
foreach ($special_opening_times as $date_array) {
    $current_datetime = strtotime($date_array['date'] . ' ' . $date_array['open']);
    if (strtotime($reference_datetime) < $current_datetime) {
        $next_datetime = $date_array['date'] . ' ' . $date_array['open'];
        break;
    }
}

// Output the next closest datetime
echo $next_datetime;

Which seems to work as expected, however I still need to find the next closest opening date and time from the weekly opening hours, and I’m at a total loss on how to do it. Could anyone shed some light. Thanks.