Time Range Array problems with PHP

I am trying to write an application for booking a time slot at an airfield, basically there is an open and close period and time interval, the application then loops between the two time values and displays a select dropdown.

I need to build in the option for the airfield to block out time ranges, so for example every Thursday between 10:00am and 12:00pm the airfield is closed to bookings, I need to build this into the loop but cannot get it working. It needs to be day specific (Mon-Sun) rather than date specific as the airfield will be closed every specified day each week for the same time period.

Here is my code so far, can anyone help please?

<?php
$open_from = "09:00";
$open_to = "17:00";
$interval = "15 mins";	
$today_number = date('w');
$intervals = array(
array(
'day' => '4',
'start' => '10:00',
'end' => '12:00',
),
array(
'day' => '4',
'start' => '12:30',
'end' => '13:30',
),
array(
'day' => '5',
'start' => '15:30',
'end' => '16:00',
),
);	
if(!isset($_GET['date'])){			  		
$date = date('d-m-Y');  		
}else{  		
$date = $_GET['date'];  		
} 
function create_time_range($start, $end, $interval) { 
$start_time = strtotime($start); 
$end_time   = strtotime($end); 
$current    = time(); 
$add_time   = strtotime('+'.$interval, $current); 
$diff       = $add_time-$current; 
$times = array(); 
while ($start_time < $end_time) { 
$times[] = $start_time; 
$start_time += $diff; 
} 
$times[] = $start_time; 
return $times; 
}
$times = create_time_range($open_from, $open_to, $interval);
foreach ($times as $key => $time) { 
$times[$key] = date($date.'H:i', $time); 
foreach($intervals as $key2 => $item) {
if($intervals[$key2]['day']==$today_number && date('H:i',$time) == $intervals[$key2]['start'] && date('H:i',$time) == $intervals[$key2]['end']){
echo "yes";
}else{
echo "no";
}
echo "<option value='".date('H:i', $timestamp)."'>".date('H:i',$time)."</option><br>";  	
//echo $intervals[$key]['day']." - ".$intervals[$key]['start']." - ".$intervals[$key]['end'];
//echo "<br>";
}
}
?>

In response to your question, you can achieve your desire result by using the following code:

if(!isset($_GET['date']))
$date = date('d-m-Y');
else
$date = $_GET['date'];
$startTime     = '09:00';
$endTime       = '17:00';
$interval      = 15; // minutes
$day           = date('N', strtotime($date));
$bookedSlots = array(
array(
'day' => '4',
'start' => '10:00',
'end' => '12:00',
),
array(
'day' => '4',
'start' => '12:30',
'end' => '13:30',
),
array(
'day' => '5',
'start' => '15:30',
'end' => '16:00',
),
);
function fetchTimeIntervals($startTime, $endTime, $intervalMinutes) {
global $day,$bookedSlots;
$htmlContent = '';
// Convert start and end times to DateTime objects
$start  = new DateTime($startTime);
$end    = new DateTime($endTime);
// Create an interval object based on the specified minutes
$interval = DateInterval::createFromDateString($intervalMinutes.' minutes');
// Create a date period object based on the start, end, and interval
$period = new DatePeriod($start, $interval, $end);
// Iterate through each interval and check each slot whether it is booked or not
foreach ($period as $slot) {
foreach ($bookedSlots as $subArr) {
$isSlotBooked = false;
$bookedSlotStartTime = new DateTime($subArr['start']);
$bookedSlotEndTime   = new DateTime($subArr['end']);
if($subArr['day'] == $day && $bookedSlotStartTime->getTimestamp()-$slot->getTimestamp() <= 0 && $bookedSlotEndTime->getTimestamp()-$slot->getTimestamp() > 0)
$isSlotBooked = true;
}
$disableClass = ($isSlotBooked) ? 'disabled' : '';
$slotTime     = $slot->format("H:i");
$htmlContent .= "<option value='{$slotTime}' {$disableClass}>{$slotTime}</option>";
}
return $htmlContent;
}
echo $timeIntervals = fetchTimeIntervals($startTime, $endTime, $intervalMinutes);
?>

Try this way:

$interval = "15 minutes";
...
$current    = time();
add_time   = strtotime($current.'+'.$interval);

Also can you guve us more info about eventual error throwed. Eventually enable debugging:

ini_set('display_errors', 1);
ini_set('display_startup_errors', 1);
error_reporting(E_ALL);

UPDATE 1<br/>
Ok inside the foreach you try to modify the same array you are looping ($times[$key]) and doesn't seems to have sense.

Check this out. I hope I've understood your problem right and provided the desired solution.

<?php
$startTime     = '09:00';
$endTime       = '17:00';
$interval      = 15; // minutes
$weekNumber    = date('w');
$excludedSlots = [
['day' => '4', 'start' => '10:00', 'end' => '12:00'],
['day' => '4', 'start' => '12:30', 'end' => '13:30'],
['day' => '5', 'start' => '15:30', 'end' => '16:00']
];
$timeRange = generateTimeRange($startTime, $endTime, $interval, $weekNumber, $excludedSlots);
echo $timeRange;
function generateTimeRange($startTime, $endTime, $interval, $weekNumber, $excludedSlots) {
$timeRange = '';
$currentTime = $startTime;
while ($currentTime <= $endTime) {
$isExcluded = false;
foreach ($excludedSlots as $excludedSlot) {
if ($weekNumber == $excludedSlot['day'] && $currentTime >= $excludedSlot['start'] && $currentTime < $excludedSlot['end']) {
$isExcluded = true;
break;
}
}
if (!$isExcluded) {
$timeRange .= "<option value='{$currentTime}'>{$currentTime}</option>";
} else {
$timeRange .= "<option value='{$currentTime}' disabled>{$currentTime} (Blocked)</option>";
}
$currentTime = date('H:i', strtotime($currentTime) + ($interval * 60));
}
return $timeRange;
}
?>

Here is the updated code tested on local machine

<?php
$open_from = "09:00";
$open_to = "17:00";
$interval = "15 mins";  
$today_number = date('w');
$intervals = array(
array(
'day' => '4',
'start' => '10:00',
'end' => '12:00',
),
array(
'day' => '4',
'start' => '12:30',
'end' => '13:30',
),
array(
'day' => '5',
'start' => '15:30',
'end' => '16:00',
),
);  
if(!isset($_GET['date'])){                  
$date = date('d-m-Y');          
}else{          
$date = $_GET['date'];          
} 
$times = create_time_range($open_from, $open_to, $interval);
foreach ($times as $key => $time) { 
$day = date('w', strtotime($date));
$timeFrame = date('H:i', $time);
foreach ($intervals as $slot) {
if ($day == $slot['day'] && $timeFrame >= $slot['start'] && $timeFrame < $slot['end']) {
echo 'No </br>';
} else {
echo 'Yes </br>';
}
}
}
function create_time_range($start, $end, $interval) { 
$start_time = strtotime($start); 
$end_time   = strtotime($end); 
$current    = time(); 
$add_time   = strtotime('+'.$interval, $current); 
$diff       = $add_time-$current; 
$times = array(); 
while ($start_time < $end_time) { 
$times[] = $start_time; 
$start_time += $diff; 
} 
$times[] = $start_time; 
return $times; 
}