<?php

/**
 * Implements hook_ENTITY_TYPE_update() for Drutopia article content.
 */
function geo_citation_article_update(Drupal\Core\Entity\EntityInterface $entity)
{
  $article_type = $entity->field_article_type->getValue();
  // If it's not a GEO Original article, there's nothing for us to do.
  if (!$article_type == 6) {
    return;
  }
}

/**
 * Implements hook_entity_extra_field_info().
 */
function geo_citation_entity_extra_field_info() {
  $extra = [];
  $extra['node']['article']['display']['geo_citation'] = [
    'label' => t('GEO Citation'),
    'description' => t('Re-presents title, author, date and other information in a standard citeable format.'),
    'weight' => 90,
  ];
  return $extra;
}

/**
 * Implements hook_ENTITY_TYPE_view() for Drutopia articles.
 */
function geo_citation_article_view(array &$build, \Drupal\Core\Entity\EntityInterface $entity, \Drupal\Core\Entity\Display\EntityViewDisplayInterface $display, $view_mode) {

}