class EntityDisplayRepository

class EntityDisplayRepository implements EntityDisplayRepositoryInterface {
    use UseCacheBackendTrait;
    use StringTranslationTrait;
    
    /**
     * Static cache of display modes information.
     *
     * @var array
     */
    protected $displayModeInfo = [];
    
    /**
     * The language manager.
     *
     * @var \Drupal\Core\Language\LanguageManagerInterface
     */
    protected $languageManager;
    
    /**
     * The entity type manager.
     *
     * @var \Drupal\Core\Entity\EntityTypeManagerInterface
     */
    protected $entityTypeManager;
    
    /**
     * The module handler.
     *
     * @var \Drupal\Core\Extension\ModuleHandlerInterface
     */
    protected $moduleHandler;
    
    /**
     * Constructs a new EntityDisplayRepository.
     *
     * @param \Drupal\Core\Entity\EntityTypeManagerInterface $entity_type_manager
     *   The entity type manager.
     * @param \Drupal\Core\Extension\ModuleHandlerInterface $module_handler
     *   The module handler.
     * @param \Drupal\Core\Cache\CacheBackendInterface $cache_backend
     *   The cache backend.
     * @param \Drupal\Core\Language\LanguageManagerInterface $language_manager
     *   The language manager.
     */
    public function __construct(EntityTypeManagerInterface $entity_type_manager, ModuleHandlerInterface $module_handler, CacheBackendInterface $cache_backend, LanguageManagerInterface $language_manager) {
        $this->entityTypeManager = $entity_type_manager;
        $this->moduleHandler = $module_handler;
        $this->cacheBackend = $cache_backend;
        $this->languageManager = $language_manager;
    }
    
    /**
     * {@inheritdoc}
     */
    public function getAllViewModes() {
        return $this->getAllDisplayModesByEntityType('view_mode');
    }
    
    /**
     * {@inheritdoc}
     */
    public function getViewModes($entity_type_id) {
        return $this->getDisplayModesByEntityType('view_mode', $entity_type_id);
    }
    
    /**
     * {@inheritdoc}
     */
    public function getAllFormModes() {
        return $this->getAllDisplayModesByEntityType('form_mode');
    }
    
    /**
     * {@inheritdoc}
     */
    public function getFormModes($entity_type_id) {
        return $this->getDisplayModesByEntityType('form_mode', $entity_type_id);
    }
    
    /**
     * Gets the entity display mode info for all entity types.
     *
     * @param string $display_type
     *   The display type to be retrieved. It can be "view_mode" or "form_mode".
     *
     * @return array
     *   The display mode info for all entity types.
     */
    protected function getAllDisplayModesByEntityType($display_type) {
        if (!isset($this->displayModeInfo[$display_type])) {
            $key = 'entity_' . $display_type . '_info';
            $entity_type_id = 'entity_' . $display_type;
            $langcode = $this->languageManager
                ->getCurrentLanguage(LanguageInterface::TYPE_INTERFACE)
                ->getId();
            if ($cache = $this->cacheGet("{$key}:{$langcode}")) {
                $this->displayModeInfo[$display_type] = $cache->data;
            }
            else {
                $this->displayModeInfo[$display_type] = [];
                foreach ($this->entityTypeManager
                    ->getStorage($entity_type_id)
                    ->loadMultiple() as $display_mode) {
                    [
                        $display_mode_entity_type,
                        $display_mode_name,
                    ] = explode('.', $display_mode->id(), 2);
                    $this->displayModeInfo[$display_type][$display_mode_entity_type][$display_mode_name] = $display_mode->toArray();
                }
                $this->moduleHandler
                    ->alter($key, $this->displayModeInfo[$display_type]);
                $this->cacheSet("{$key}:{$langcode}", $this->displayModeInfo[$display_type], CacheBackendInterface::CACHE_PERMANENT, [
                    'entity_types',
                    'entity_field_info',
                ]);
            }
        }
        return $this->displayModeInfo[$display_type];
    }
    
    /**
     * Gets the entity display mode info for a specific entity type.
     *
     * @param string $display_type
     *   The display type to be retrieved. It can be "view_mode" or "form_mode".
     * @param string $entity_type_id
     *   The entity type whose display mode info should be returned.
     *
     * @return array
     *   The display mode info for a specific entity type.
     */
    protected function getDisplayModesByEntityType($display_type, $entity_type_id) {
        if (isset($this->displayModeInfo[$display_type][$entity_type_id])) {
            return $this->displayModeInfo[$display_type][$entity_type_id];
        }
        else {
            $display_modes = $this->getAllDisplayModesByEntityType($display_type);
            if (isset($display_modes[$entity_type_id])) {
                return $display_modes[$entity_type_id];
            }
        }
        return [];
    }
    
    /**
     * {@inheritdoc}
     */
    public function getViewModeOptions($entity_type) {
        return $this->getDisplayModeOptions('view_mode', $entity_type);
    }
    
    /**
     * {@inheritdoc}
     */
    public function getFormModeOptions($entity_type_id) {
        return $this->getDisplayModeOptions('form_mode', $entity_type_id);
    }
    
    /**
     * {@inheritdoc}
     */
    public function getViewModeOptionsByBundle($entity_type_id, $bundle) {
        return $this->getDisplayModeOptionsByBundle('view_mode', $entity_type_id, $bundle);
    }
    
    /**
     * {@inheritdoc}
     */
    public function getFormModeOptionsByBundle($entity_type_id, $bundle) {
        return $this->getDisplayModeOptionsByBundle('form_mode', $entity_type_id, $bundle);
    }
    
    /**
     * Gets an array of display mode options.
     *
     * @param string $display_type
     *   The display type to be retrieved. It can be "view_mode" or "form_mode".
     * @param string $entity_type_id
     *   The entity type whose display mode options should be returned.
     *
     * @return array
     *   An array of display mode labels, keyed by the display mode ID.
     */
    protected function getDisplayModeOptions($display_type, $entity_type_id) {
        $options = [
            'default' => $this->t('Default'),
        ];
        foreach ($this->getDisplayModesByEntityType($display_type, $entity_type_id) as $mode => $settings) {
            $options[$mode] = $settings['label'];
        }
        return $options;
    }
    
    /**
     * Returns an array of enabled display mode options by bundle.
     *
     * @param $display_type
     *   The display type to be retrieved. It can be "view_mode" or "form_mode".
     * @param string $entity_type_id
     *   The entity type whose display mode options should be returned.
     * @param string $bundle
     *   The name of the bundle.
     *
     * @return array
     *   An array of display mode labels, keyed by the display mode ID.
     */
    protected function getDisplayModeOptionsByBundle($display_type, $entity_type_id, $bundle) {
        // Collect all the entity's display modes.
        $options = $this->getDisplayModeOptions($display_type, $entity_type_id);
        // Filter out modes for which the entity display is disabled
        // (or non-existent).
        $load_ids = [];
        // Get the list of available entity displays for the current bundle.
        foreach (array_keys($options) as $mode) {
            $load_ids[] = $entity_type_id . '.' . $bundle . '.' . $mode;
        }
        // Load the corresponding displays.
        $displays = $this->entityTypeManager
            ->getStorage($display_type == 'form_mode' ? 'entity_form_display' : 'entity_view_display')
            ->loadMultiple($load_ids);
        // Unset the display modes that are not active or do not exist.
        foreach (array_keys($options) as $mode) {
            $display_id = $entity_type_id . '.' . $bundle . '.' . $mode;
            if (!isset($displays[$display_id]) || !$displays[$display_id]->status()) {
                unset($options[$mode]);
            }
        }
        return $options;
    }
    
    /**
     * {@inheritdoc}
     */
    public function clearDisplayModeInfo() {
        $this->displayModeInfo = [];
        return $this;
    }
    
    /**
     * {@inheritdoc}
     */
    public function getViewDisplay($entity_type, $bundle, $view_mode = self::DEFAULT_DISPLAY_MODE) {
        $storage = $this->entityTypeManager
            ->getStorage('entity_view_display');
        // Try loading the display from configuration; if not found, create a fresh
        // display object. We do not preemptively create new entity_view_display
        // configuration entries for each existing entity type and bundle whenever a
        // new view mode becomes available. Instead, configuration entries are only
        // created when a display object is explicitly configured and saved.
        $entity_view_display = $storage->load($entity_type . '.' . $bundle . '.' . $view_mode);
        if (!$entity_view_display) {
            $entity_view_display = $storage->create([
                'targetEntityType' => $entity_type,
                'bundle' => $bundle,
                'mode' => $view_mode,
                'status' => TRUE,
            ]);
        }
        return $entity_view_display;
    }
    
    /**
     * {@inheritdoc}
     */
    public function getFormDisplay($entity_type, $bundle, $form_mode = self::DEFAULT_DISPLAY_MODE) {
        $storage = $this->entityTypeManager
            ->getStorage('entity_form_display');
        // Try loading the entity from configuration; if not found, create a fresh
        // entity object. We do not preemptively create new entity form display
        // configuration entries for each existing entity type and bundle whenever a
        // new form mode becomes available. Instead, configuration entries are only
        // created when an entity form display is explicitly configured and saved.
        $entity_form_display = $storage->load($entity_type . '.' . $bundle . '.' . $form_mode);
        if (!$entity_form_display) {
            $entity_form_display = $storage->create([
                'targetEntityType' => $entity_type,
                'bundle' => $bundle,
                'mode' => $form_mode,
                'status' => TRUE,
            ]);
        }
        return $entity_form_display;
    }

}