opencase/modules/opencase_entities/opencase_entities.module

<?php

/**
 * @file
 * Contains opencase_entities.module.
 */

use Drupal\Core\Routing\RouteMatchInterface;
use Drupal\opencase_entities\CaseInvolvement;

/**
 * Implements hook_help().
 */
function opencase_entities_help($route_name, RouteMatchInterface $route_match) {
  switch ($route_name) {
    // Main module help for the opencase_entities module.
    case 'help.page.opencase_entities':
      $output = '';
      $output .= '<h3>' . t('About') . '</h3>';
      $output .= '<p>' . t('Entity Types for OpenCase') . '</p>';
      return $output;

    default:
  }
}

/**
 * Implements hook_theme().
 */
function opencase_entities_theme() {
  $theme = [];
  $theme['oc_organisation_relation'] = [
    'render element' => 'elements',
    'file' => 'oc_organisation_relation.page.inc',
    'template' => 'oc_organisation_relation',
  ];
  $theme['oc_organisation_relation_content_add_list'] = [
    'render element' => 'content',
    'variables' => ['content' => NULL],
    'file' => 'oc_organisation_relation.page.inc',
  ];
  $theme['opencase_entities'] = [
    'render element' => 'children',
  ];
  $theme['oc_actor'] = [
    'render element' => 'elements',
    'file' => 'oc_actor.page.inc',
    'template' => 'oc_actor',
  ];
  $theme['oc_actor_content_add_list'] = [
    'render element' => 'content',
    'variables' => ['content' => NULL],
    'file' => 'oc_actor.page.inc',
  ];
  $theme['oc_activity'] = [
    'render element' => 'elements',
    'file' => 'oc_activity.page.inc',
    'template' => 'oc_activity',
  ];
  $theme['oc_activity_content_add_list'] = [
    'render element' => 'content',
    'variables' => ['content' => NULL],
    'template' => 'oc-activity-content-add-list',
    'file' => 'oc_activity.page.inc',
  ];
  $theme['oc_organisation'] = [
    'render element' => 'elements',
    'file' => 'oc_organisation.page.inc',
    'template' => 'oc_organisation',
  ];
  $theme['oc_organisation_content_add_list'] = [
    'render element' => 'content',
    'variables' => ['content' => NULL],
    'file' => 'oc_organisation.page.inc',
  ];
  $theme['oc_event'] = [
    'render element' => 'elements',
    'file' => 'oc_event.page.inc',
    'template' => 'oc_event',
  ];
  $theme['oc_event_content_add_list'] = [
    'render element' => 'content',
    'variables' => ['content' => NULL],
    'file' => 'oc_event.page.inc',
  ];
  return $theme;
}

/** 
 * Get the value of a url parameter and return it in a array
 * so that it can be used as a default callback for an entity reference field.
 */
function opencase_entities_get($key) {
  \Drupal::request()->query->get($key);
}

/**
* Implements hook_theme_suggestions_HOOK().
*/
function opencase_entities_theme_suggestions_oc_actor(array $variables) {
  $suggestions = [];
  $entity = $variables['elements']['#oc_actor'];
  $sanitized_view_mode = strtr($variables['elements']['#view_mode'], '.', '_');

  $suggestions[] = 'oc_actor__' . $sanitized_view_mode;
  $suggestions[] = 'oc_actor__' . $entity->bundle();
  $suggestions[] = 'oc_actor__' . $entity->bundle() . '__' . $sanitized_view_mode;
  $suggestions[] = 'oc_actor__' . $entity->id();
  $suggestions[] = 'oc_actor__' . $entity->id() . '__' . $sanitized_view_mode;
  return $suggestions;
}

/**
* Implements hook_theme_suggestions_HOOK().
*/
function opencase_entities_theme_suggestions_oc_activity(array $variables) {
  $suggestions = [];
  $entity = $variables['elements']['#oc_activity'];
  $sanitized_view_mode = strtr($variables['elements']['#view_mode'], '.', '_');

  $suggestions[] = 'oc_activity__' . $sanitized_view_mode;
  $suggestions[] = 'oc_activity__' . $entity->bundle();
  $suggestions[] = 'oc_activity__' . $entity->bundle() . '__' . $sanitized_view_mode;
  $suggestions[] = 'oc_activity__' . $entity->id();
  $suggestions[] = 'oc_activity__' . $entity->id() . '__' . $sanitized_view_mode;
  return $suggestions;
}


/**
 * Implements hook_theme_suggestions_HOOK().
 */
function opencase_entities_theme_suggestions_oc_organisation(array $variables) {
  $suggestions = [];
  $entity = $variables['elements']['#oc_organisation'];
  $sanitized_view_mode = strtr($variables['elements']['#view_mode'], '.', '_');

  $suggestions[] = 'oc_organisation__' . $sanitized_view_mode;
  $suggestions[] = 'oc_organisation__' . $entity->bundle();
  $suggestions[] = 'oc_organisation__' . $entity->bundle() . '__' . $sanitized_view_mode;
  $suggestions[] = 'oc_organisation__' . $entity->id();
  $suggestions[] = 'oc_organisation__' . $entity->id() . '__' . $sanitized_view_mode;
  return $suggestions;
}

/**
 * Implements hook_theme_suggestions_HOOK().
 */
function opencase_entities_theme_suggestions_oc_event(array $variables) {
  $suggestions = [];
  $entity = $variables['elements']['#oc_event'];
  $sanitized_view_mode = strtr($variables['elements']['#view_mode'], '.', '_');

  $suggestions[] = 'oc_event__' . $sanitized_view_mode;
  $suggestions[] = 'oc_event__' . $entity->bundle();
  $suggestions[] = 'oc_event__' . $entity->bundle() . '__' . $sanitized_view_mode;
  $suggestions[] = 'oc_event__' . $entity->id();
  $suggestions[] = 'oc_event__' . $entity->id() . '__' . $sanitized_view_mode;
  return $suggestions;
}


/**
 * Implements hook_theme_suggestions_HOOK().
 */
function opencase_entities_theme_suggestions_oc_organisation_relation(array $variables) {
  $suggestions = [];
  $entity = $variables['elements']['#oc_organisation_relation'];
  $sanitized_view_mode = strtr($variables['elements']['#view_mode'], '.', '_');

  $suggestions[] = 'oc_organisation_relation__' . $sanitized_view_mode;
  $suggestions[] = 'oc_organisation_relation__' . $entity->bundle();
  $suggestions[] = 'oc_organisation_relation__' . $entity->bundle() . '__' . $sanitized_view_mode;
  $suggestions[] = 'oc_organisation_relation__' . $entity->id();
  $suggestions[] = 'oc_organisation_relation__' . $entity->id() . '__' . $sanitized_view_mode;
  return $suggestions;
}