Initial commit

app/Services/AvailabilityService.php

@@ -0,0 +1,56 @@
+<?php
+
+namespace App\Services;
+
+use App\Models\ExternalBusyWindow;
+use Carbon\Carbon;
+
+class AvailabilityService
+{
+    public function __construct(
+        private readonly string $tz = 'Europe/London',
+        private readonly int $bufferMins = 40
+    ) {}
+
+    /**
+     * Check if a single slot (date + time) is blocked by external busy windows,
+     * considering a travel buffer before start and after end.
+     */
+    public function isSlotBlockedByExternalBusy(string $dateYmd, string $timeHi, int $durationMins = 60): bool
+    {
+        // Build slot window in UTC
+        $slotStartLocal = Carbon::createFromFormat('Y-m-d H:i', "{$dateYmd} {$timeHi}", $this->tz);
+        $slotStartUtc   = $slotStartLocal->clone()->utc();
+        $slotEndUtc     = $slotStartUtc->clone()->addMinutes($durationMins);
+
+        // Expand comparison bounds by buffer
+        $slotStartMinusBuffer = $slotStartUtc->clone()->subMinutes($this->bufferMins);
+        $slotEndPlusBuffer    = $slotEndUtc->clone()->addMinutes($this->bufferMins);
+
+        // Overlap: busyStart < slotEnd+buffer  AND  busyEnd > slotStart-buffer
+        return ExternalBusyWindow::query()
+            ->where('starts_at', '<', $slotEndPlusBuffer)
+            ->where('ends_at',   '>', $slotStartMinusBuffer)
+            ->exists();
+    }
+
+    /**
+     * For block-booking: given a set of future candidate dates for a given time,
+     * return the subset that are blocked (with reasons).
+     *
+     * @param array<string> $dateListYmd  e.g. ['2025-10-27','2025-11-03', ...]
+     * @return array<int, array{date:string, blocked:bool}>
+     */
+    public function checkSeriesConflicts(array $dateListYmd, string $timeHi, int $durationMins = 60): array
+    {
+        $results = [];
+        foreach ($dateListYmd as $ymd) {
+            $blocked = $this->isSlotBlockedByExternalBusy($ymd, $timeHi, $durationMins);
+            $results[] = [
+                'date'    => $ymd,
+                'blocked' => $blocked,
+            ];
+        }
+        return $results;
+    }
+}