unsupervised-scheduler/src/Offering/ClassSlotReconciler.php

<?php
declare(strict_types=1);

namespace Unsupervised\Schedular\Offering;

use Unsupervised\Schedular\Availability\AvailabilityRepository;

/**
 * Keeps an instructor's open availability out of the way of the group classes
 * they teach. When a group class is scheduled (an assigned instructor plus a
 * date, time, and duration), each session occupies the instructor: any open
 * private-booking slot that overlaps a session is removed so students cannot
 * book the instructor at the class time, and any already-booked slot that
 * overlaps is reported as a conflict for the studio to resolve by hand — a
 * booked lesson is never silently deleted.
 */
class ClassSlotReconciler {

	public function __construct( private AvailabilityRepository $availability ) {}

	/**
	 * Reconcile the assigned instructor's availability with the class schedule.
	 *
	 * @return array{removed: int, conflicts: list<string>} The number of open
	 *         slots cleared, and the start datetime (`Y-m-d H:i:s`) of each booked
	 *         slot that still clashes with a session.
	 */
	public function reconcile( Offering $offering ): array {
		if ( Offering::KIND_GROUP_CLASS !== $offering->kind || $offering->instructorId <= 0 ) {
			return [
				'removed'   => 0,
				'conflicts' => [],
			];
		}

		$removed   = 0;
		$conflicts = [];

		foreach ( $offering->sessionWindows() as $window ) {
			foreach ( $this->availability->findOverlapping( $offering->instructorId, $window['start'], $window['end'] ) as $slot ) {
				if ( $slot->isBooked ) {
					$conflicts[] = $slot->startDt;
					continue;
				}

				if ( null !== $slot->id && $this->availability->delete( $slot->id ) ) {
					++$removed;
				}
			}
		}

		return [
			'removed'   => $removed,
			'conflicts' => $conflicts,
		];
	}
}