roblib_bee_limits/roblib_bee_limits.module

<?php

/**
 * @file
 * Primary module hooks for roblib_bee_limits module.
 *
 */

use Drupal\Core\Form\FormBase;
use Drupal\Core\Form\FormStateInterface;
use Drupal\node\Entity\Node;

/**
 * Implements hook_form_FORM_ID_alter.
 *
 * @param $form
 * @param \Drupal\Core\Form\FormStateInterface $form_state
 * @param $form_id
 */
function roblib_bee_limits_form_bee_add_reservation_form_alter(&$form, FormStateInterface $form_state, $form_id){
  $form['#validate'][] = 'roblib_bee_limits_validate_reservation';
}

/**
 * Additional form validation for bee_add_reservation_form.
 *
 * Limits hourly bookings.
 *
 * @param $form
 * @param \Drupal\Core\Form\FormStateInterface $form_state
 *
 * @throws \Exception
 */
function roblib_bee_limits_validate_reservation($form, FormStateInterface $form_state) {
  $user = \Drupal\user\Entity\User::load(\Drupal::currentUser()->id());
  $roles = $user->getRoles();
  debug($roles, 'pp-roles', TRUE);
  $values = $form_state->getValues();
  $node = Node::load($values['node']);
  $config_factory = \Drupal::configFactory();
  $bee_settings = $config_factory->get('node.type.' . $node->bundle())->get('bee');
  // we only want to limit hourly reservations
  if($bee_settings['bookable_type'] != 'hourly') {
    return;
  }
  $start_date = $values['start_date'];
  $end_date = $values['end_date'];
  $start_timestamp = new \DateTime($start_date->format('Y-m-d H:i'));
  $end_timestamp = new \DateTime($end_date->format('Y-m-d H:i'));
  $minutes_diff = abs($end_timestamp->getTimestamp() - $start_timestamp->getTimestamp()) / 60;
  debug($minutes_diff, 'pp-minutesdiff', TRUE);
  if($minutes_diff > 120) {
    $form_state->setError($form, t('Reservation exceeded max booking time of 2 hours.'));
  }
}