class ModerationInformation

class ModerationInformation implements ModerationInformationInterface {
    use StringTranslationTrait;
    
    /**
     * The entity type manager.
     *
     * @var \Drupal\Core\Entity\EntityTypeManagerInterface
     */
    protected $entityTypeManager;
    
    /**
     * The bundle information service.
     *
     * @var \Drupal\Core\Entity\EntityTypeBundleInfoInterface
     */
    protected $bundleInfo;
    
    /**
     * Creates a new ModerationInformation instance.
     *
     * @param \Drupal\Core\Entity\EntityTypeManagerInterface $entity_type_manager
     *   The entity type manager.
     * @param \Drupal\Core\Entity\EntityTypeBundleInfoInterface $bundle_info
     *   The bundle information service.
     */
    public function __construct(EntityTypeManagerInterface $entity_type_manager, EntityTypeBundleInfoInterface $bundle_info) {
        $this->entityTypeManager = $entity_type_manager;
        $this->bundleInfo = $bundle_info;
    }
    
    /**
     * {@inheritdoc}
     */
    public function isModeratedEntity(EntityInterface $entity) {
        if (!$entity instanceof ContentEntityInterface) {
            return FALSE;
        }
        if (!$this->shouldModerateEntitiesOfBundle($entity->getEntityType(), $entity->bundle())) {
            return FALSE;
        }
        return $this->entityTypeManager
            ->getHandler($entity->getEntityTypeId(), 'moderation')
            ->isModeratedEntity($entity);
    }
    
    /**
     * {@inheritdoc}
     */
    public function isModeratedEntityType(EntityTypeInterface $entity_type) {
        $bundles = $this->bundleInfo
            ->getBundleInfo($entity_type->id());
        return !empty(array_column($bundles, 'workflow'));
    }
    
    /**
     * {@inheritdoc}
     */
    public function canModerateEntitiesOfEntityType(EntityTypeInterface $entity_type) {
        return $entity_type->hasHandlerClass('moderation');
    }
    
    /**
     * {@inheritdoc}
     */
    public function shouldModerateEntitiesOfBundle(EntityTypeInterface $entity_type, $bundle) {
        if ($this->canModerateEntitiesOfEntityType($entity_type)) {
            $bundles = $this->bundleInfo
                ->getBundleInfo($entity_type->id());
            return isset($bundles[$bundle]['workflow']);
        }
        return FALSE;
    }
    
    /**
     * {@inheritdoc}
     */
    public function getDefaultRevisionId($entity_type_id, $entity_id) {
        if ($storage = $this->entityTypeManager
            ->getStorage($entity_type_id)) {
            $result = $storage->getQuery()
                ->currentRevision()
                ->condition($this->entityTypeManager
                ->getDefinition($entity_type_id)
                ->getKey('id'), $entity_id)
                ->accessCheck(FALSE)
                ->execute();
            if ($result) {
                return key($result);
            }
        }
    }
    
    /**
     * {@inheritdoc}
     */
    public function getAffectedRevisionTranslation(ContentEntityInterface $entity) {
        foreach ($entity->getTranslationLanguages() as $language) {
            $translation = $entity->getTranslation($language->getId());
            if (!$translation->isDefaultRevision() && $translation->isRevisionTranslationAffected()) {
                return $translation;
            }
        }
    }
    
    /**
     * {@inheritdoc}
     */
    public function hasPendingRevision(ContentEntityInterface $entity) {
        $result = FALSE;
        if ($this->isModeratedEntity($entity)) {
            
            /** @var \Drupal\Core\Entity\RevisionableStorageInterface $storage */
            $storage = $this->entityTypeManager
                ->getStorage($entity->getEntityTypeId());
            $latest_revision_id = $storage->getLatestTranslationAffectedRevisionId($entity->id(), $entity->language()
                ->getId());
            $default_revision_id = $entity->isDefaultRevision() && !$entity->isNewRevision() && ($revision_id = $entity->getRevisionId()) ? $revision_id : $this->getDefaultRevisionId($entity->getEntityTypeId(), $entity->id());
            if ($latest_revision_id !== NULL && $latest_revision_id != $default_revision_id) {
                
                /** @var \Drupal\Core\Entity\ContentEntityInterface $latest_revision */
                $latest_revision = $storage->loadRevision($latest_revision_id);
                $result = !$latest_revision->wasDefaultRevision();
            }
        }
        return $result;
    }
    
    /**
     * {@inheritdoc}
     */
    public function isLiveRevision(ContentEntityInterface $entity) {
        $workflow = $this->getWorkflowForEntity($entity);
        return $entity->isLatestRevision() && $entity->isDefaultRevision() && $entity->moderation_state->value && $workflow->getTypePlugin()
            ->getState($entity->moderation_state->value)
            ->isPublishedState();
    }
    
    /**
     * {@inheritdoc}
     */
    public function isDefaultRevisionPublished(ContentEntityInterface $entity) {
        $workflow = $this->getWorkflowForEntity($entity);
        $default_revision = $this->entityTypeManager
            ->getStorage($entity->getEntityTypeId())
            ->load($entity->id());
        // If no default revision could be loaded, the entity has not yet been
        // saved. In this case the moderation_state of the unsaved entity can be
        // used, since once saved it will become the default.
        $default_revision = $default_revision ?: $entity;
        // Ensure we are checking all translations of the default revision.
        if ($default_revision instanceof TranslatableInterface && $default_revision->isTranslatable()) {
            // Loop through each language that has a translation.
            foreach ($default_revision->getTranslationLanguages() as $language) {
                // Load the translated revision.
                $translation = $default_revision->getTranslation($language->getId());
                // If the moderation state is empty, it was not stored yet so no point
                // in doing further work.
                $moderation_state = $translation->moderation_state->value;
                if (!$moderation_state) {
                    continue;
                }
                // Return TRUE if a translation with a published state is found.
                if ($workflow->getTypePlugin()
                    ->getState($moderation_state)
                    ->isPublishedState()) {
                    return TRUE;
                }
            }
        }
        return $workflow->getTypePlugin()
            ->getState($default_revision->moderation_state->value)
            ->isPublishedState();
    }
    
    /**
     * {@inheritdoc}
     */
    public function getWorkflowForEntity(ContentEntityInterface $entity) {
        return $this->getWorkflowForEntityTypeAndBundle($entity->getEntityTypeId(), $entity->bundle());
    }
    
    /**
     * {@inheritdoc}
     */
    public function getWorkflowForEntityTypeAndBundle($entity_type_id, $bundle_id) {
        $bundles = $this->bundleInfo
            ->getBundleInfo($entity_type_id);
        if (isset($bundles[$bundle_id]['workflow'])) {
            return $this->entityTypeManager
                ->getStorage('workflow')
                ->load($bundles[$bundle_id]['workflow']);
        }
        return NULL;
    }
    
    /**
     * {@inheritdoc}
     */
    public function getUnsupportedFeatures(EntityTypeInterface $entity_type) {
        $features = [];
        // Test if entity is publishable.
        if (!$entity_type->entityClassImplements(EntityPublishedInterface::class)) {
            $features['publishing'] = $this->t("@entity_type_plural_label do not support publishing statuses. For example, even after transitioning from a published workflow state to an unpublished workflow state they will still be visible to site visitors.", [
                '@entity_type_plural_label' => $entity_type->getCollectionLabel(),
            ]);
        }
        return $features;
    }
    
    /**
     * {@inheritdoc}
     */
    public function getOriginalState(ContentEntityInterface $entity) {
        $state = NULL;
        $workflow_type = $this->getWorkflowForEntity($entity)
            ->getTypePlugin();
        if (!$entity->isNew() && !$this->isFirstTimeModeration($entity)) {
            
            /** @var \Drupal\Core\Entity\RevisionableStorageInterface $storage */
            $storage = $this->entityTypeManager
                ->getStorage($entity->getEntityTypeId());
            
            /** @var \Drupal\Core\Entity\ContentEntityInterface $original_entity */
            $original_entity = $storage->loadRevision($entity->getLoadedRevisionId());
            if (!$entity->isDefaultTranslation() && $original_entity->hasTranslation($entity->language()
                ->getId())) {
                $original_entity = $original_entity->getTranslation($entity->language()
                    ->getId());
            }
            if ($workflow_type->hasState($original_entity->moderation_state->value)) {
                $state = $workflow_type->getState($original_entity->moderation_state->value);
            }
        }
        return $state ?: $workflow_type->getInitialState($entity);
    }
    
    /**
     * Determines if this entity is being moderated for the first time.
     *
     * If the previous version of the entity has no moderation state, we assume
     * that means it predates the presence of moderation states.
     *
     * @param \Drupal\Core\Entity\ContentEntityInterface $entity
     *   The entity being moderated.
     *
     * @return bool
     *   TRUE if this is the entity's first time being moderated, FALSE otherwise.
     */
    protected function isFirstTimeModeration(ContentEntityInterface $entity) {
        
        /** @var \Drupal\Core\Entity\RevisionableStorageInterface $storage */
        $storage = $this->entityTypeManager
            ->getStorage($entity->getEntityTypeId());
        $original_entity = $storage->loadRevision($storage->getLatestRevisionId($entity->id()));
        if ($original_entity) {
            $original_id = $original_entity->moderation_state;
        }
        return !($entity->moderation_state && $original_entity && $original_id);
    }

}