class ContentTranslationController

class ContentTranslationController extends ControllerBase {
    
    /**
     * The content translation manager.
     *
     * @var \Drupal\content_translation\ContentTranslationManagerInterface
     */
    protected $manager;
    
    /**
     * The entity field manager.
     *
     * @var \Drupal\Core\Entity\EntityFieldManagerInterface
     */
    protected $entityFieldManager;
    
    /**
     * Initializes a content translation controller.
     *
     * @param \Drupal\content_translation\ContentTranslationManagerInterface $manager
     *   A content translation manager instance.
     * @param \Drupal\Core\Entity\EntityFieldManagerInterface $entity_field_manager
     *   The entity field manager service.
     */
    public function __construct(ContentTranslationManagerInterface $manager, EntityFieldManagerInterface $entity_field_manager) {
        $this->manager = $manager;
        $this->entityFieldManager = $entity_field_manager;
    }
    
    /**
     * {@inheritdoc}
     */
    public static function create(ContainerInterface $container) {
        return new static($container->get('content_translation.manager'), $container->get('entity_field.manager'));
    }
    
    /**
     * Populates target values with the source values.
     *
     * @param \Drupal\Core\Entity\ContentEntityInterface $entity
     *   The entity being translated.
     * @param \Drupal\Core\Language\LanguageInterface $source
     *   The language to be used as source.
     * @param \Drupal\Core\Language\LanguageInterface $target
     *   The language to be used as target.
     */
    public function prepareTranslation(ContentEntityInterface $entity, LanguageInterface $source, LanguageInterface $target) {
        $source_langcode = $source->getId();
        
        /** @var \Drupal\Core\Entity\ContentEntityInterface $source_translation */
        $source_translation = $entity->getTranslation($source_langcode);
        $target_translation = $entity->addTranslation($target->getId(), $source_translation->toArray());
        // Make sure we do not inherit the affected status from the source values.
        if ($entity->getEntityType()
            ->isRevisionable()) {
            $target_translation->setRevisionTranslationAffected(NULL);
        }
        
        /** @var \Drupal\user\UserInterface $user */
        $user = $this->entityTypeManager()
            ->getStorage('user')
            ->load($this->currentUser()
            ->id());
        $metadata = $this->manager
            ->getTranslationMetadata($target_translation);
        // Update the translation author to current user, as well the translation
        // creation time.
        $metadata->setAuthor($user);
        $metadata->setCreatedTime(REQUEST_TIME);
        $metadata->setSource($source_langcode);
    }
    
    /**
     * Builds the translations overview page.
     *
     * @param \Drupal\Core\Routing\RouteMatchInterface $route_match
     *   The route match.
     * @param string $entity_type_id
     *   (optional) The entity type ID.
     *
     * @return array
     *   Array of page elements to render.
     */
    public function overview(RouteMatchInterface $route_match, $entity_type_id = NULL) {
        
        /** @var \Drupal\Core\Entity\ContentEntityInterface $entity */
        $entity = $route_match->getParameter($entity_type_id);
        $account = $this->currentUser();
        $handler = $this->entityTypeManager()
            ->getHandler($entity_type_id, 'translation');
        $manager = $this->manager;
        $entity_type = $entity->getEntityType();
        $use_latest_revisions = $entity_type->isRevisionable() && ContentTranslationManager::isPendingRevisionSupportEnabled($entity_type_id, $entity->bundle());
        // Start collecting the cacheability metadata, starting with the entity and
        // later merge in the access result cacheability metadata.
        $cacheability = CacheableMetadata::createFromObject($entity);
        $languages = $this->languageManager()
            ->getLanguages();
        $original = $entity->getUntranslated()
            ->language()
            ->getId();
        $translations = $entity->getTranslationLanguages();
        $field_ui = $this->moduleHandler()
            ->moduleExists('field_ui') && $account->hasPermission('administer ' . $entity_type_id . ' fields');
        $rows = [];
        $show_source_column = FALSE;
        
        /** @var \Drupal\Core\Entity\ContentEntityStorageInterface $storage */
        $storage = $this->entityTypeManager()
            ->getStorage($entity_type_id);
        $default_revision = $storage->load($entity->id());
        if ($this->languageManager()
            ->isMultilingual()) {
            // Determine whether the current entity is translatable.
            $translatable = FALSE;
            foreach ($this->entityFieldManager
                ->getFieldDefinitions($entity_type_id, $entity->bundle()) as $instance) {
                if ($instance->isTranslatable()) {
                    $translatable = TRUE;
                    break;
                }
            }
            // Show source-language column if there are non-original source langcodes.
            $additional_source_langcodes = array_filter(array_keys($translations), function ($langcode) use ($entity, $original, $manager) {
                $source = $manager->getTranslationMetadata($entity->getTranslation($langcode))
                    ->getSource();
                return $source != $original && $source != LanguageInterface::LANGCODE_NOT_SPECIFIED;
            });
            $show_source_column = !empty($additional_source_langcodes);
            foreach ($languages as $language) {
                $language_name = $language->getName();
                $langcode = $language->getId();
                // If the entity type is revisionable, we may have pending revisions
                // with translations not available yet in the default revision. Thus we
                // need to load the latest translation-affecting revision for each
                // language to be sure we are listing all available translations.
                if ($use_latest_revisions) {
                    $entity = $default_revision;
                    $latest_revision_id = $storage->getLatestTranslationAffectedRevisionId($entity->id(), $langcode);
                    if ($latest_revision_id) {
                        
                        /** @var \Drupal\Core\Entity\ContentEntityInterface $latest_revision */
                        $latest_revision = $storage->loadRevision($latest_revision_id);
                        // Make sure we do not list removed translations, i.e. translations
                        // that have been part of a default revision but no longer are.
                        if (!$latest_revision->wasDefaultRevision() || $default_revision->hasTranslation($langcode)) {
                            $entity = $latest_revision;
                        }
                    }
                    $translations = $entity->getTranslationLanguages();
                }
                $options = [
                    'language' => $language,
                ];
                $add_url = $entity->toUrl('drupal:content-translation-add', $options)
                    ->setRouteParameter('source', $original)
                    ->setRouteParameter('target', $language->getId());
                $edit_url = $entity->toUrl('drupal:content-translation-edit', $options)
                    ->setRouteParameter('language', $language->getId());
                $delete_url = $entity->toUrl('drupal:content-translation-delete', $options)
                    ->setRouteParameter('language', $language->getId());
                $operations = [
                    'data' => [
                        '#type' => 'operations',
                        '#links' => [],
                    ],
                ];
                $links =& $operations['data']['#links'];
                if (array_key_exists($langcode, $translations)) {
                    // Existing translation in the translation set: display status.
                    $translation = $entity->getTranslation($langcode);
                    $metadata = $manager->getTranslationMetadata($translation);
                    $source = $metadata->getSource() ?: LanguageInterface::LANGCODE_NOT_SPECIFIED;
                    $is_original = $langcode == $original;
                    $label = $entity->getTranslation($langcode)
                        ->label() ?? $entity->id();
                    $link = [
                        'url' => $entity->toUrl(),
                    ];
                    if (!empty($link['url'])) {
                        $link['url']->setOption('language', $language);
                        $row_title = Link::fromTextAndUrl($label, $link['url'])->toString();
                    }
                    if (empty($link['url'])) {
                        $row_title = $is_original ? $label : $this->t('n/a');
                    }
                    // If the user is allowed to edit the entity we point the edit link to
                    // the entity form, otherwise if we are not dealing with the original
                    // language we point the link to the translation form.
                    $update_access = $entity->access('update', NULL, TRUE);
                    $translation_access = $handler->getTranslationAccess($entity, 'update');
                    $cacheability = $cacheability->merge(CacheableMetadata::createFromObject($update_access))
                        ->merge(CacheableMetadata::createFromObject($translation_access));
                    if ($update_access->isAllowed() && $entity_type->hasLinkTemplate('edit-form')) {
                        $links['edit']['url'] = $entity->toUrl('edit-form');
                        $links['edit']['language'] = $language;
                    }
                    elseif (!$is_original && $translation_access->isAllowed()) {
                        $links['edit']['url'] = $edit_url;
                    }
                    if (isset($links['edit'])) {
                        $links['edit']['title'] = $this->t('Edit');
                    }
                    $status = [
                        'data' => [
                            '#type' => 'inline_template',
                            '#template' => '<span class="status">{% if status %}{{ "Published"|t }}{% else %}{{ "Not published"|t }}{% endif %}</span>{% if outdated %} <span class="marker">{{ "outdated"|t }}</span>{% endif %}',
                            '#context' => [
                                'status' => $metadata->isPublished(),
                                'outdated' => $metadata->isOutdated(),
                            ],
                        ],
                    ];
                    if ($is_original) {
                        $language_name = $this->t('<strong>@language_name (Original language)</strong>', [
                            '@language_name' => $language_name,
                        ]);
                        $source_name = $this->t('n/a');
                    }
                    else {
                        
                        /** @var \Drupal\Core\Access\AccessResultInterface $delete_route_access */
                        $delete_route_access = \Drupal::service('content_translation.delete_access')->checkAccess($translation);
                        $cacheability->addCacheableDependency($delete_route_access);
                        if ($delete_route_access->isAllowed()) {
                            $source_name = isset($languages[$source]) ? $languages[$source]->getName() : $this->t('n/a');
                            $delete_access = $entity->access('delete', NULL, TRUE);
                            $translation_access = $handler->getTranslationAccess($entity, 'delete');
                            $cacheability->addCacheableDependency($delete_access)
                                ->addCacheableDependency($translation_access);
                            if ($delete_access->isAllowed() && $entity_type->hasLinkTemplate('delete-form')) {
                                $links['delete'] = [
                                    'title' => $this->t('Delete'),
                                    'url' => $entity->toUrl('delete-form'),
                                    'language' => $language,
                                ];
                            }
                            elseif ($translation_access->isAllowed()) {
                                $links['delete'] = [
                                    'title' => $this->t('Delete'),
                                    'url' => $delete_url,
                                ];
                            }
                        }
                        else {
                            $this->messenger()
                                ->addWarning($this->t('The "Delete translation" action is only available for published translations.'), FALSE);
                        }
                    }
                }
                else {
                    // No such translation in the set yet: help user to create it.
                    $row_title = $source_name = $this->t('n/a');
                    $source = $entity->language()
                        ->getId();
                    $create_translation_access = $handler->getTranslationAccess($entity, 'create');
                    $cacheability = $cacheability->merge(CacheableMetadata::createFromObject($create_translation_access));
                    if ($source != $langcode && $create_translation_access->isAllowed()) {
                        if ($translatable) {
                            $links['add'] = [
                                'title' => $this->t('Add'),
                                'url' => $add_url,
                            ];
                        }
                        elseif ($field_ui) {
                            $url = new Url('language.content_settings_page');
                            // Link directly to the fields tab to make it easier to find the
                            // setting to enable translation on fields.
                            $links['nofields'] = [
                                'title' => $this->t('No translatable fields'),
                                'url' => $url,
                            ];
                        }
                    }
                    $status = $this->t('Not translated');
                }
                if ($show_source_column) {
                    $rows[] = [
                        $language_name,
                        $row_title,
                        $source_name,
                        $status,
                        $operations,
                    ];
                }
                else {
                    $rows[] = [
                        $language_name,
                        $row_title,
                        $status,
                        $operations,
                    ];
                }
            }
        }
        if ($show_source_column) {
            $header = [
                $this->t('Language'),
                $this->t('Translation'),
                $this->t('Source language'),
                $this->t('Status'),
                $this->t('Operations'),
            ];
        }
        else {
            $header = [
                $this->t('Language'),
                $this->t('Translation'),
                $this->t('Status'),
                $this->t('Operations'),
            ];
        }
        $build['#title'] = $this->t('Translations of %label', [
            '%label' => $entity->label() ?? $entity->id(),
        ]);
        // Add metadata to the build render array to let other modules know about
        // which entity this is.
        $build['#entity'] = $entity;
        $cacheability->addCacheTags($entity->getCacheTags())
            ->applyTo($build);
        $build['content_translation_overview'] = [
            '#theme' => 'table',
            '#header' => $header,
            '#rows' => $rows,
        ];
        return $build;
    }
    
    /**
     * Builds an add translation page.
     *
     * @param \Drupal\Core\Language\LanguageInterface $source
     *   The language of the values being translated. Defaults to the entity
     *   language.
     * @param \Drupal\Core\Language\LanguageInterface $target
     *   The language of the translated values. Defaults to the current content
     *   language.
     * @param \Drupal\Core\Routing\RouteMatchInterface $route_match
     *   The route match object from which to extract the entity type.
     * @param string $entity_type_id
     *   (optional) The entity type ID.
     *
     * @return array
     *   A processed form array ready to be rendered.
     */
    public function add(LanguageInterface $source, LanguageInterface $target, RouteMatchInterface $route_match, $entity_type_id = NULL) {
        
        /** @var \Drupal\Core\Entity\ContentEntityInterface $entity */
        $entity = $route_match->getParameter($entity_type_id);
        // In case of a pending revision, make sure we load the latest
        // translation-affecting revision for the source language, otherwise the
        // initial form values may not be up-to-date.
        if (!$entity->isDefaultRevision() && ContentTranslationManager::isPendingRevisionSupportEnabled($entity_type_id, $entity->bundle())) {
            
            /** @var \Drupal\Core\Entity\ContentEntityStorageInterface $storage */
            $storage = $this->entityTypeManager()
                ->getStorage($entity->getEntityTypeId());
            $revision_id = $storage->getLatestTranslationAffectedRevisionId($entity->id(), $source->getId());
            if ($revision_id != $entity->getRevisionId()) {
                $entity = $storage->loadRevision($revision_id);
            }
        }
        // @todo Exploit the upcoming hook_entity_prepare() when available.
        // See https://www.drupal.org/node/1810394.
        $this->prepareTranslation($entity, $source, $target);
        // @todo Provide a way to figure out the default form operation. Maybe like
        //   $operation = isset($info['default_operation']) ? $info['default_operation'] : 'default';
        //   See https://www.drupal.org/node/2006348.
        // Use the add form handler, if available, otherwise default.
        $operation = $entity->getEntityType()
            ->hasHandlerClass('form', 'add') ? 'add' : 'default';
        $form_state_additions = [];
        $form_state_additions['langcode'] = $target->getId();
        $form_state_additions['content_translation']['source'] = $source;
        $form_state_additions['content_translation']['target'] = $target;
        $form_state_additions['content_translation']['translation_form'] = !$entity->access('update');
        return $this->entityFormBuilder()
            ->getForm($entity, $operation, $form_state_additions);
    }
    
    /**
     * Builds the edit translation page.
     *
     * @param \Drupal\Core\Language\LanguageInterface $language
     *   The language of the translated values. Defaults to the current content
     *   language.
     * @param \Drupal\Core\Routing\RouteMatchInterface $route_match
     *   The route match object from which to extract the entity type.
     * @param string $entity_type_id
     *   (optional) The entity type ID.
     *
     * @return array
     *   A processed form array ready to be rendered.
     */
    public function edit(LanguageInterface $language, RouteMatchInterface $route_match, $entity_type_id = NULL) {
        $entity = $route_match->getParameter($entity_type_id);
        // @todo Provide a way to figure out the default form operation. Maybe like
        //   $operation = isset($info['default_operation']) ? $info['default_operation'] : 'default';
        //   See https://www.drupal.org/node/2006348.
        // Use the edit form handler, if available, otherwise default.
        $operation = $entity->getEntityType()
            ->hasHandlerClass('form', 'edit') ? 'edit' : 'default';
        $form_state_additions = [];
        $form_state_additions['langcode'] = $language->getId();
        $form_state_additions['content_translation']['translation_form'] = TRUE;
        return $this->entityFormBuilder()
            ->getForm($entity, $operation, $form_state_additions);
    }

}