single_node_form_alerts.module

<?php

/**
 * @file
 * Contains single_node_form_alerts.module.
 */

use Drupal\Core\Routing\RouteMatchInterface;
use Drupal\Core\Form\FormStateInterface;

/**
 * Implements hook_help().
 */
function single_node_form_alerts_help($route_name, RouteMatchInterface $route_match) {
  switch ($route_name) {
    // Main module help for the single_node_form_alerts module.
    case 'help.page.single_node_form_alerts':
      $output = '';
      $output .= '<h3>' . t('About') . '</h3>';
      $output .= '<p>' . t('Provide alerts on node forms specific to a single node') . '</p>';
      return $output;

    default:
  }
}

/**
 * Implements hook_form_BASE_FORM_ID_alter().
 */
function single_node_form_alerts_form_node_form_alter(&$form, FormStateInterface $form_state, $form_id)
{
  $node = $form_state->getFormObject()->getEntity();
  $message_config = \Drupal::state()->get('single_node_form_alerts.node_' . $node->id(), []);
  $form['#attached']['library'][] = 'single_node_form_alerts/node_form_alerts';


  if (!empty($message_config['top_message'])) {
    $msg = !empty($form['#prefix']) ? $form['#prefix'] : '';
    $form['#prefix'] = $msg.format_node_form_message($message_config['top_message']);
  }

  if (!empty($message_config['bottom_message'])) {
    $msg = !empty($form['actions']['#prefix']) ? $form['actions']['#prefix'] : '';
    $form['actions']['#prefix'] = format_node_form_message($message_config['bottom_message']) . $msg;
  }
  foreach ($message_config as $k => $v) {
    $key = str_replace('_message', '', $k);
    if (isset($form[$key])) {
      $msg = !empty($form[$key]['#prefix']) ? $form[$key]['#prefix'] : '';
      $form[$key]['#prefix'] = $msg . format_node_form_message($v);
    }
  }
}

/**
 * @param string $message
 *   The saved message for the field.
 * @return string
 *   It is wrapped in div to show as a very visible block of text.
 */
function format_node_form_message($message) {
  return sprintf('<div class="single-node-form-message">%s</div>', strip_tags($message, '<p><a><b><i><br>'));
}