Minutes interval between two times past midnight in php - php

Question

Users are allowed to pick a time for delivery up until the closing time of the store which can be 1am.
The list should should show all times up to 1am even if it is after midnight.
example 1: User arrives at 18:00 they see 18:00, 18:30, 19:00 and so on up until 00:30, 01:00
example 2: user arrives at 00:10 should see
00:30, 01:00 not
01:00, 01:30, 02:00, 02:30 etc because after midnight has become a has become a new day/date.
I am getting 30 minute time intervals between two times, it is fine as long as both times are in the same day e.g. 17:00 and 23:00. If the end time is past midnight I am not able to get the intervals so 17:00 to 01:00 doesn't give any intervals.
I understand 01:00 is another day but not quite sure how to fix it using a dynamic date. I keep thinking current day +1 will be fine unless it is after mindight then it will be an extra day if that makes sense.
Here's my code:
$timestamp = time() + 60*60;
$earliest = date("h:i ",$timestamp);
$period = new DatePeriod(
new DateTime($earliest),
new DateInterval('PT30M'),
new DateTime('01:00')
);
foreach ($period as $date) {
echo '<option value="">'.$date->format("H:i").'</option>';
}
Because 24:00 works as 00:00 I tried 25:00 but that didn't work. Any help appreciated!
UPDATE: following the answer below coverted to dynamic date, if I use date like:
$start = date('Y-m-d H:i');
$startdate = date('Y-m-d');
$end = date('Y-m-d', strtotime($startdate . ' +1 day'))." 01:00";
$period = new DatePeriod(
DateTime::createFromFormat('Y-m-d H:i','2020-04-03 17:00'),
new DateInterval('PT30M'),
DateTime::createFromFormat('Y-m-d H:i','2020-04-04 01:00')
);
After midnight it's another day added on which is problematic.

Answer 1

You also have to mention exact dates and not just time as 01:00. Because this way, it assumes the current date and hence you really can't have a time period between 17:00 and 01:00 on the same day. Below is how you would do it:
<?php
$period = new DatePeriod(
DateTime::createFromFormat('Y-m-d H:i','2020-04-03 17:00'),
new DateInterval('PT30M'),
DateTime::createFromFormat('Y-m-d H:i','2020-04-04 01:00')
);
foreach ($period as $date) {
echo $date->format("H:i"),PHP_EOL;
}
Demo: https://3v4l.org/5sj9Z
Update:
Since you have only times and not dates, you create DateTime objects, compare them, add 1 day to end time if it's smaller and then loop over the intervals using DatePeriod
<?php
$times = [
['18:00','01:00'],
['17:00','23:00'],
['00:10','01:00']
];
foreach($times as $time){
$start_time = DateTime::createFromFormat('H:i',$time[0]);
$end_time = DateTime::createFromFormat('H:i',$time[1]);
if($end_time < $start_time){
$end_time->add(new DateInterval('P1D'));
}
$period = new DatePeriod(
$start_time,
new DateInterval('PT30M'),
$end_time
);
echo $start_time->format('Y-m-d H:i:s'),' ',$end_time->format('Y-m-d H:i:s'),PHP_EOL;
foreach ($period as $date) {
echo $date->format("H:i"),PHP_EOL;
}
echo PHP_EOL;
}
Demo: https://3v4l.org/Ldpst

Answer 2

You can lose the whole timestamp calculation and have it all handled by DateTime:
// here we get the next round delivery time
$nextAvailableHalfHour = getNextHalfHourMark();
$todayMidnight = new DateTime('today'); // this creates today with time 00:00:00
$todayOneOclock = new DateTime('today 01:00'); // this creates today with time 01:00:00
// this condition says if we're now between midnight and 1 o'clock, use today
// otherwise use tomorrow
$endDate = $nextAvailableHalfHour >= $todayMidnight && $nextAvailableHalfHour <= $todayOneOclock
? $todayOneOclock
: new DateTime('tomorrow 01:00'); // create specific time tomorrow
$period = new DatePeriod(
$nextAvailableHalfHour,
new DateInterval('PT30M'),
$endDate
);
/**
* Gets the next available time with round half hour (:00 or :30).
*/
function getNextHalfHourMark(): DateTime
{
$now = new DateTime(); // create current date and time
$currentMinutes = (int) $now->format('i');
// if we are between :00 and :30
if ($currentMinutes > 0 && $currentMinutes < 30) {
// set to :30 minutes of current hour
$now->setTime($now->format('H'), 30);
// else if we are between :30 and :00
} elseif ($currentMinutes > 30 && $currentMinutes <= 59) {
// set to :00 minutes of next hour
$now->setTime($now->format('H') + 1, 00);
}
return $now;
}
The tomorrow and today strings are enabled by relative formats.