<?php

/**
 * @file
 * This module adds a "Read more" extrafield to all node displays.
 */

/**
 * Implements hook_theme().
 */
function readmore_extrafield_theme($existing, $type, $theme, $path) {
  return [
    'readmore_extrafield' => [
      'variables' => [
        'title' => NULL,
        'url' => NULL,
        'attributes' => [],
        'entity' => NULL,
        'view_mode' => '',
      ],
    ],
  ];
}

/**
 * Implements hook_theme_suggestions_HOOK().
 */
function readmore_extrafield_theme_suggestions_readmore_extrafield(array $variables) {
  if (empty($variables['entity']) || empty($variables['view_mode'])) {
    return;
  }
  $entity = $variables['entity'];
  $entity_type = $entity->getEntityTypeId();
  $bundle = $entity->bundle();
  $entity_id = $entity->id();
  $sanitized_view_mode = !empty($variables['view_mode']) ? strtr($variables['view_mode'], '.', '_') : '';

  $suggestions = [];
  $suggestions[] = 'readmore_extrafield__' . $sanitized_view_mode;
  $suggestions[] = 'readmore_extrafield__' . $entity_type;
  $suggestions[] = 'readmore_extrafield__' . $entity_type . '__' . $sanitized_view_mode;
  $suggestions[] = 'readmore_extrafield__' . $entity_type . '__' . $bundle;
  $suggestions[] = 'readmore_extrafield__' . $entity_type . '__' . $bundle . '__' . $sanitized_view_mode;
  $suggestions[] = 'readmore_extrafield__' . $entity_type . '__' . $entity_id;
  $suggestions[] = 'readmore_extrafield__' . $entity_type . '__' . $entity_id . '__' . $sanitized_view_mode;

  return $suggestions;
}