manifest/web/modules/custom/yufu_admin/yufu_admin.module

<?php

/**
 * @file
 * Primary module hooks for Yufu Admin module.
 */

use Drupal\Core\Entity\EntityInterface;
use Drupal\Core\Url;
use Drupal\node\NodeInterface;

/**
 * Implements hook_entity_operation().
 */
function yufu_admin_entity_operation(EntityInterface $entity) {
  $operations = [];
  $entityType = $entity->getEntityType();
  // @TODO Only for entity node - should we add other entities as well?
  if ($entityType->id() === 'node' && \Drupal::currentUser()->hasPermission('use jsonapi operation link')) {
    // Build the url.
    $url = Url::fromRoute(sprintf('jsonapi.%s--%s.individual', $entityType->id(), $entity->bundle()),
      ['entity' => $entity->uuid()]
    );
    $operations['view-jsonapi-output'] = [
      'title' => t('jsonapi Output'),
      'weight' => 50,
      'url' => $url,
    ];
  }
  return $operations;
}

/**
 * Implements hook_mail().
 */
function yufu_admin_mail($key, &$message, $params) {
  $options = ['langcode' => $message['langcode']];

  switch ($key) {
    case 'concept_drafted':
      $message['from'] = \Drupal::config('system.site')->get('mail');
      $message['subject'] = t('[YUFU] New concept draft: @title', ['@title' => $params['node_title']], $options);
      $message['body'][] = $params['message'];
      break;
    case 'concept_approved':
      $message['from'] = \Drupal::config('system.site')->get('mail');
      $message['subject'] = t('[YUFU] Concept changes approved: @title', ['@title' => $params['node_title']], $options);
      $message['body'][] = $params['message'];
      break;
    case 'concept_rejected':
      $message['from'] = \Drupal::config('system.site')->get('mail');
      $message['subject'] = t('[YUFU] Concept changes rejected: @title', ['@title' => $params['node_title']], $options);
      $message['body'][] = $params['message'];
  }
}

/**
 * Implements hook_ENTITY_TYPE_presave().
 */
function yufu_admin_node_presave(EntityInterface $entity) {
  if ($entity instanceOf NodeInterface && $entity->bundle() == 'concept') {
    // Get transition: concept_drafted, concept_approved, concept_rejected.
    if ($entity->isNew()) {
      $transition = 'concept_drafted';
    }
    else {
      $transition = _yufu_admin_get_node_transition($entity);
    }
    switch ($transition) {
      case 'stay_draft':
      case 'concept_drafted':
        // Send email to editors.
        $params = _yufu_admin_concept_drafted_mail($entity);
        $result = _yufu_admin_send_email($transition, $params['to'], $params);
        _yufu_admin_status_message($result['result'], $transition, $entity, $params['to']);
        break;
      case 'concept_approved':
        // Send email to revision creator (user).
        // @TODO Maybe notify other editors.
        $params = _yufu_admin_concept_approved_get_message($entity);
        $result = _yufu_admin_send_email($transition, $params['to'], $params);
        _yufu_admin_status_message($result['result'], $transition, $entity, $params['to']);
        break;
      case 'concept_rejectd':
        // Send email to revision creator (user).
        // This transition happens on revision delete.
        // Curently it is dead.
        // @TODO https://git.kompot.si/yufu/manifest/issues/45
        break;
    }
  }
}

/**
 * Compare original node moderation state with current state.
 *
 * @param \Drupal\node\NodeInterface $node
 *   Node to check transition on.
 *
 * @return string|null
 *   Name of the transition.
 */
function _yufu_admin_get_node_transition(NodeInterface $node) {
  $original = $node->original ?? NULL;
  $moderation_state = $node->moderation_state->value;
  $previous_state = $original?->moderation_state->value ?? NULL;
  if ($moderation_state == 'draft' && in_array($previous_state, ['published', NULL])) {
    return 'concept_drafted';
  }
  else if ($moderation_state == 'published' && $previous_state == 'draft') {
    return 'concept_approved';
  }
  else if ($moderation_state == 'published' && $previous_state == 'published') {
    return 'stay_published';
  }
  else if ($moderation_state == 'draft' && $previous_state == 'draft') {
    return 'stay_draft';
  }
  return NULL;
}

/**
 * Notify user that their concept (revision) was published.
 *
 * @param \Drupal\node\NodeInterface $node
 *   Concept node that was transitioned into published state.
 */
function _yufu_admin_concept_drafted_mail(NodeInterface $node) {
  $to = _yufu_admin_get_all_editors_emails();
  if ($node->isNew()) {
    $params['message'] = t('New concept created: @title - @url', [
      '@title' => $node->getTitle(),
      '@url' => !$node->isNew() ? $node?->toUrl()?->toString() : '',
    ]);
  }
  else {
    $params['message'] = t('New changes to concept proposed: @title - @url', [
      '@title' => $node->getTitle(),
      '@url' => !$node->isNew() ? $node?->toUrl()?->toString() : '',
    ]);
  }
  $params['node_title'] = $node->getTitle();
  $params['to'] = implode(',', $to);
  return $params;
}

/**
 * Function for sending emails.
 *
 * @param string $key
 *   Transition of a concept.
 * @param string $to
 *   List of recipients.
 * @param array $params
 *   Message parameters.
 *
 * @return array
 *   Mail manager response.
 */
function _yufu_admin_send_email($key = '', $to = '', $params = []) {
  $mailManager = \Drupal::service('plugin.manager.mail');
  $module = 'yufu_admin';
  $langcode = \Drupal::currentUser()->getPreferredLangcode();
  $send = TRUE;
  $result = $mailManager->mail($module, $key, $to, $langcode, $params, NULL, $send);
  return $result;
}

/**
 * Add notifications on sending of emails.
 */
function _yufu_admin_status_message($result, $transition = '', $node = NULL, $recipients = '') {
  $log = t('For transition @transition of concept @title (@nid) to recipients @recipients.', [
    '@transition' => $transition,
    '@title' => $node?->getTitle() ?? t('Unknown'),
    '@nid' => $node?->id() ?? '',
    '@recipients' => $recipients,
  ]);
  if ($result !== TRUE) {
    $message = t('There was a problem sending your message and it was not sent. ');
    Drupal::logger('yufu_admin')->error($message . $log);
    Drupal::messenger()->addError($message . $log);
  }
  else {
    $message = t('Your message has been sent. ');
    Drupal::logger('yufu_admin')->notice($message . $log);
    Drupal::messenger()->addStatus($message . $log);
  }
}

/**
 * Get a list of emails of all editors.
 *
 * @return array
 *   List of strings.
 */
function _yufu_admin_get_all_editors_emails() {
  $user_storage = \Drupal::entityTypeManager()->getStorage('user');
  $ids = $user_storage->getQuery()
    ->condition('status', 1)
    ->condition('roles', 'editor')
    ->accessCheck(FALSE)
    ->execute();
  $editors = $user_storage->loadMultiple($ids);
  $emails = [];
  foreach ($editors as $editor) {
    /* @var \Drupal\user\UserInterface $user */
    if ($email = $editor?->getEmail()) {
      $emails[] = $email;
    }
    else {
      \Drupal::logger('yufu_admin')->warning('@editor (@uid) is missing email.',[
        '@editor' => $editor?->getDisplayName() ?? '',
        '@uid' => $editor->id(),
      ]);
    }
  }
  return $emails;
}

/**
 * Notify user that their concept (revision) was published.
 *
 * @param \Drupal\node\NodeInterface $node
 *   Concept node that was transitioned into published state.
 */
function _yufu_admin_concept_approved_get_message(NodeInterface $node) {
  // To the revision's authors.
  // @TODO - to make this work properly, we should get a list of all authors of
  // unpublished revisions so far since the last published revision.
  if ($to = _yufu_admin_get_pioneer_email($node)) {
    $params['message'] = t('Your proposal of changes to concept were approved: @title - @url', [
      '@title' => $node->getTitle(),
      '@url' => $node?->toUrl()?->toString() ?? '',
    ]);
  }
  else {
    $to = implode(',', _yufu_admin_get_all_editors_emails());
    $params['message'] = t('Published changes not attributed to any of knownn users: @title - @url', [
      '@title' => $node->getTitle(),
      '@url' => !$node->isNew() ? $node?->toUrl()?->toString() : '',
    ]);
  }
  $params['node_title'] = $node->getTitle();
  $params['to'] = $to;
  return $params;
}

/**
 * Get the email of person (pioneer) that worked on proposed changes.
 *
 * @return string|NULL
 *   List of strings.
 */
function _yufu_admin_get_pioneer_email(NodeInterface $node) {
  // $email = $node->uid->entity;
  if ($original = $node->original) {
    $user = $original->getRevisionUser();
    $email = $user->getEmail();
    return $email ?? NULL;
  }
  // @TODO: Make this code nicer.
  $user = $node->getRevisionUser();
  $email = $user->getEmail();
  return $email ?? NULL;
}


/**
 * Get a list of emails of people that worked on proposed changes.
 *
 * @return array
 *   List of strings.
 */
function _yufu_admin_get_all_pioneer_emails() {
  // @TODO: Think it through if it is really needed.
  return [];
}