degov-8.x-2.0/modules/degov_node_event/degov_node_event.module

<?php

use Drupal\degov_common\Common;
use Drupal\Core\Form\FormStateInterface;
use Drupal\Core\Datetime\DrupalDateTime;

/**
 * Implements hook_preprocess().
 */
function degov_node_event_preprocess(&$variables, $hook, &$info) {
  // Add template suggestions and libraries implemented in this module.
  Common::addThemeSuggestions($variables, $hook, $info, [
    'module_name' => 'degov_node_event',
    'entity_type' => 'node',
    'entity_bundles' => ['event'],
    'entity_view_modes' => ['teaser', 'latest', 'slideshow'],
  ]);
}

/**
 * Implements hook_views_pre_render().
 */
function degov_node_event_views_pre_render(\Drupal\views\ViewExecutable $view) {
  if ($view->storage->id() == "events" && $view->current_display == 'calendar_widget') {
    $view->element['#attached']['library'][] = 'degov_node_event/degov_events';
  }
}

/**
 * Preprocess event nodes.
 *
 * @param $variables
 */
function degov_node_event_preprocess_node(&$variables) {
  $node = $variables['node'];
  if ($node->bundle() == 'event') {
    $variables['start_date_timestamp'] = FALSE;
    $variables['end_date_timestamp'] = FALSE;
    $timezone = drupal_get_user_timezone();

    if (!$node->get('field_event_date')->isEmpty()) {
      $startDateObject = new \Drupal\Core\Datetime\DrupalDateTime($node->get('field_event_date')->value, 'UTC');
      $startDateObject->setTimeZone(timezone_open($timezone));
      $variables['start_date_timestamp'] = $startDateObject->getTimestamp();
    }
    if (!$node->get('field_event_date_end')->isEmpty()) {
      $endDateObject = new \Drupal\Core\Datetime\DrupalDateTime($node->get('field_event_date_end')->value, 'UTC');
      $endDateObject->setTimeZone(timezone_open($timezone));
      $variables['end_date_timestamp'] = $endDateObject->getTimestamp();
    }
  }
}

/**
 * Event calender date form alter
 *
 * @param $form
 * @param \Drupal\Core\Form\FormStateInterface $form_state
 * @param $form_id
 */
function degov_node_event_form_alter(&$form, \Drupal\Core\Form\FormStateInterface $form_state, $form_id) {
  if ($form_id == 'views_exposed_form') {
    // Apply our alter only for events views display.
    $view_names = ['events'];
    $view = $form_state->getStorage('view');
    if (in_array($view['view']->id(), $view_names)) {
      /** @var \Drupal\Core\Datetime\Entity\DateFormat $format */
      $format = \Drupal::entityTypeManager()->getStorage('date_format')->load('short');
      $pattern = 'd.m.Y';
      if ($format) {
        $pattern = $format->getPattern();
      }
      /*if (!empty($form['from'])) {
        $form['from']['#attributes']['data-drupal-date-format'] = $pattern;
      }
      if (!empty($form['to'])) {
        $form['to']['#attributes']['data-drupal-date-format'] = $pattern;
      }*/
      // Custom validate function.
      $form['#validate'][] = 'degov_node_event_date_form_validate';
    }
  }

  if ($form_id == 'node_event_edit_form' || $form_id == 'node_event_form') {
    $form['#validate'][] = 'degov_node_event_node_form_validate';
  }
}

/**
 * Event calender date form custom validation
 * Add 24 hours in date_to filed to get current date events
 *
 * @param $form
 * @param \Drupal\Core\Form\FormStateInterface $form_state
 */
function degov_node_event_date_form_validate($form, \Drupal\Core\Form\FormStateInterface $form_state) {
  // Check if the exposed filter is supposed to filter by end date.
  if ($form_state->getValue('to')) {
    $date_to = $form_state->getValue('to');
    // Change the date to the end of the day.
    $date_to = $date_to . ' ' . '23:59:00';
    $form_state->setValue('to', $date_to);
  }
}

/**
 * Make sure the begin date is before the end date.
 *
 * @param $form
 * @param \Drupal\Core\Form\FormStateInterface $form_state
 */
function degov_node_event_node_form_validate($form, FormStateInterface $form_state) {
  $from = $form_state->getValue('field_event_date');
  $till = $form_state->getValue('field_event_date_end');

  if (isset($from[0]['value']) && $from[0]['value'] instanceof DrupalDateTime && isset($till[0]['value']) && $till[0]['value'] instanceof DrupalDateTime) {
    if ($from[0]['value'] >= $till[0]['value']) {
      $form_state->setErrorByName('field_event_date', t('The start date must be earlier than the end date.'));
    }
  }
}