assets/css/components/RsvTimeSlotsStyles.css

@@ -87,7 +87,7 @@ label.rsv-slots-slot-time>input:checked + .content>.capacity {
   font-weight: 600;
 }
 
-.rsv-slots-slot:hover:not(.rsv-slots-slot-full):not(.rsv-slots-slot-selected) {
+.rsv-slots-slot:hover:not(.rsv-slots-slot-full):not(.rsv-slots-slot-too-soon):not(.rsv-slots-slot-selected) {
   border-color: #2563eb;
   background: #f5f8ff;
 }
@@ -115,6 +115,12 @@ label.rsv-slots-slot-time>input:checked + .content>.capacity {
   cursor: not-allowed;
 }
 
+/* Within minimum lead time — available but not yet bookable */
+.rsv-slots-slot-too-soon {
+  opacity: 0.45;
+  cursor: not-allowed;
+}
+
 /* Selected */
 .rsv-slots-slot-selected {
   background: #2563eb;

assets/js/elements/RsvTimeline.js

@@ -47,7 +47,7 @@ class RsvTimeline extends HTMLElement {
 
   _on_click(event) {
     const slot = event.target.closest('.rsv-slots-slot');
-    if (slot && !slot.classList.contains('rsv-slots-slot-full')) {
+    if (slot && !slot.classList.contains('rsv-slots-slot-full') && !slot.classList.contains('rsv-slots-slot-too-soon')) {
       slot.classList.toggle('rsv-slots-slot-selected');
       slot.dispatchEvent(new Event('input', { bubbles: true }));
     }
@@ -81,7 +81,7 @@ class RsvTimeline extends HTMLElement {
 
       const blocks = [];
 
-      for (const { from_minutes, to_minutes, block_size_in_minutes, occupancy: block_occ } of occupancy) {
+      for (const { from_minutes, to_minutes, block_size_in_minutes, occupancy: block_occ, lead_time_minutes } of occupancy) {
         if (from_minutes === to_minutes || block_occ.length === 0) {
           continue;
         }
@@ -89,7 +89,7 @@ class RsvTimeline extends HTMLElement {
         const from_block = parseInt(from_minutes) / block_size_in_minutes;
 
         const time_slots = block_occ.map((occ, i) =>
-          this._block(this.date, occ, block_size_in_minutes, from_block + i)
+          this._block(this.date, occ, block_size_in_minutes, from_block + i, lead_time_minutes?.[i] ?? 0)
         );
 
         const time_slot_group = document.createElement('div');
@@ -105,7 +105,7 @@ class RsvTimeline extends HTMLElement {
     }
   }
 
-  _block(date, left, block_size, idx) {
+  _block(date, left, block_size, idx, min_lead_time_minutes = 0) {
     const from = new Date(date);
     from.setHours(0, idx * block_size, 0, 0);
 
@@ -117,6 +117,7 @@ class RsvTimeline extends HTMLElement {
     cell.dataset.start_utc = from.toISOString();
     cell.dataset.end_utc   = to.toISOString();
     if (left <= 0) cell.classList.add('rsv-slots-slot-full');
+    else if (from < new Date(Date.now() + min_lead_time_minutes * 60_000)) cell.classList.add('rsv-slots-slot-too-soon');
 
     const time_el = document.createElement('span');
     time_el.classList.add('rsv-slots-slot-time');

includes/Models/RsvTimetableAvailability.php

@@ -5,17 +5,20 @@
  */
 class RsvTimetableAvailability {
     /**
-     * @param array<int,int> $occupancy Number of available seats for each time block
+     * @param array<int,int> $occupancy          Number of available seats for each time block
+     * @param array<int,int> $lead_time_minutes   Minimum lead time in minutes required for each block
      */
     public function __construct(
         public int $from_minutes,
         public int $to_minutes,
         public int $block_size_in_minutes,
-        public array $occupancy
+        public array $occupancy,
+        public array $lead_time_minutes = []
     ) { }
 
-    public function push_block(int $capacity) {
-        $this->occupancy[] = $capacity;
-        $this->to_minutes += $this->block_size_in_minutes;
+    public function push_block(int $capacity, int $min_lead_time_minutes = 0) {
+        $this->occupancy[]         = $capacity;
+        $this->lead_time_minutes[] = $min_lead_time_minutes;
+        $this->to_minutes         += $this->block_size_in_minutes;
     }
 }

includes/Services/RsvTimetableReservationService.php

@@ -39,6 +39,14 @@ class RsvTimetableReservationService {
             return false;
         }
 
+        $max_lead_time    = max(array_map(fn($c) => (int) $c->min_lead_time_minutes, $overlapping_capacity));
+        $earliest_allowed = new DateTime('now', new DateTimeZone('UTC'));
+        $earliest_allowed->modify("+{$max_lead_time} minutes");
+        if ($start_utc < $earliest_allowed) {
+            Logger::error("Reservation rejected: minimum lead time of {$max_lead_time} minutes not met for timetable_id: $timetable_id");
+            return false;
+        }
+
         $start_min = $this->time_of_day_minutes($start_utc);
         $end_min   = $this->time_of_day_minutes($end_utc);
 

includes/Services/RsvTimetableService.php

@@ -98,7 +98,8 @@ class RsvTimetableService {
                     $availabilities[] = new RsvTimetableAvailability($i * $block_length, ($i + 1) * $block_length, $block_length, []);
                 }
 
-                $availabilities[$availability_idx]->push_block($total_capacity - count($reservation_stack));
+                $max_lead_time = empty($capacity_stack) ? 0 : max(array_map(fn($x) => $x->min_lead_time_minutes, $capacity_stack));
+                $availabilities[$availability_idx]->push_block($total_capacity - count($reservation_stack), $max_lead_time);
             } else if($total_capacity === 0 && count($availabilities) !== $availability_idx) {
                 $availability_idx++;
             }