class CommentController

class CommentController extends ControllerBase {
    
    /**
     * The HTTP kernel.
     *
     * @var \Symfony\Component\HttpKernel\HttpKernelInterface
     */
    protected $httpKernel;
    
    /**
     * The comment manager service.
     *
     * @var \Drupal\comment\CommentManagerInterface
     */
    protected $commentManager;
    
    /**
     * The entity field manager.
     *
     * @var \Drupal\Core\Entity\EntityFieldManagerInterface
     */
    protected $entityFieldManager;
    
    /**
     * The entity repository.
     *
     * @var \Drupal\Core\Entity\EntityRepositoryInterface
     */
    protected $entityRepository;
    
    /**
     * Constructs a CommentController object.
     *
     * @param \Symfony\Component\HttpKernel\HttpKernelInterface $http_kernel
     *   HTTP kernel to handle requests.
     * @param \Drupal\comment\CommentManagerInterface $comment_manager
     *   The comment manager service.
     * @param \Drupal\Core\Entity\EntityTypeManagerInterface $entity_type_manager
     *   The entity type manager service.
     * @param \Drupal\Core\Entity\EntityFieldManagerInterface $entity_field_manager
     *   The entity field manager service.
     * @param \Drupal\Core\Entity\EntityRepositoryInterface $entity_repository
     *   The entity repository service.
     */
    public function __construct(HttpKernelInterface $http_kernel, CommentManagerInterface $comment_manager, EntityTypeManagerInterface $entity_type_manager, EntityFieldManagerInterface $entity_field_manager, EntityRepositoryInterface $entity_repository) {
        $this->httpKernel = $http_kernel;
        $this->commentManager = $comment_manager;
        $this->entityTypeManager = $entity_type_manager;
        $this->entityFieldManager = $entity_field_manager;
        $this->entityRepository = $entity_repository;
    }
    
    /**
     * Publishes the specified comment.
     *
     * @param \Drupal\comment\CommentInterface $comment
     *   A comment entity.
     *
     * @return \Symfony\Component\HttpFoundation\RedirectResponse
     */
    public function commentApprove(CommentInterface $comment) {
        $comment->setPublished();
        $comment->save();
        $this->messenger()
            ->addStatus($this->t('Comment approved.'));
        $permalink_uri = $comment->permalink();
        $permalink_uri->setAbsolute();
        return new RedirectResponse($permalink_uri->toString());
    }
    
    /**
     * Redirects comment links to the correct page depending on comment settings.
     *
     * Since comments are paged there is no way to guarantee which page a comment
     * appears on. Comment paging and threading settings may be changed at any
     * time. With threaded comments, an individual comment may move between pages
     * as comments can be added either before or after it in the overall
     * discussion. Therefore we use a central routing function for comment links,
     * which calculates the page number based on current comment settings and
     * returns the full comment view with the pager set dynamically.
     *
     * @param \Symfony\Component\HttpFoundation\Request $request
     *   The request of the page.
     * @param \Drupal\comment\CommentInterface $comment
     *   A comment entity.
     *
     * @return \Symfony\Component\HttpFoundation\Response
     *   The comment listing set to the page on which the comment appears.
     *
     * @throws \Symfony\Component\HttpKernel\Exception\NotFoundHttpException
     * @throws \Symfony\Component\HttpKernel\Exception\AccessDeniedHttpException
     */
    public function commentPermalink(Request $request, CommentInterface $comment) {
        if ($entity = $comment->getCommentedEntity()) {
            // Check access permissions for the entity.
            if (!$entity->access('view')) {
                throw new AccessDeniedHttpException();
            }
            $field_definition = $this->entityFieldManager
                ->getFieldDefinitions($entity->getEntityTypeId(), $entity->bundle())[$comment->getFieldName()];
            // Find the current display page for this comment.
            $page = $this->entityTypeManager()
                ->getStorage('comment')
                ->getDisplayOrdinal($comment, $field_definition->getSetting('default_mode'), $field_definition->getSetting('per_page'));
            // @todo Cleaner sub request handling.
            $subrequest_url = $entity->toUrl()
                ->setOption('query', [
                'page' => $page,
            ])
                ->toString(TRUE);
            $redirect_request = Request::create($subrequest_url->getGeneratedUrl(), 'GET', $request->query
                ->all(), $request->cookies
                ->all(), [], $request->server
                ->all());
            // Carry over the session to the subrequest.
            $redirect_request->setSession($request->getSession());
            $request->query
                ->set('page', $page);
            $response = $this->httpKernel
                ->handle($redirect_request, HttpKernelInterface::SUB_REQUEST);
            if ($response instanceof CacheableResponseInterface) {
                // @todo Once path aliases have cache tags (see
                //   https://www.drupal.org/node/2480077), add test coverage that
                //   the cache tag for a commented entity's path alias is added to the
                //   comment's permalink response, because there can be blocks or
                //   other content whose renderings depend on the subrequest's URL.
                $response->addCacheableDependency($subrequest_url);
            }
            return $response;
        }
        throw new NotFoundHttpException();
    }
    
    /**
     * The _title_callback for the page that renders the comment permalink.
     *
     * @param \Drupal\comment\CommentInterface $comment
     *   The current comment.
     *
     * @return string
     *   The translated comment subject.
     */
    public function commentPermalinkTitle(CommentInterface $comment) {
        return $this->entityRepository
            ->getTranslationFromContext($comment)
            ->label();
    }
    
    /**
     * Redirects legacy node links to the new path.
     *
     * @param \Drupal\Core\Entity\EntityInterface $node
     *   The node object identified by the legacy URL.
     *
     * @return \Symfony\Component\HttpFoundation\RedirectResponse
     *   Redirects user to new URL.
     *
     * @throws \Symfony\Component\HttpKernel\Exception\NotFoundHttpException
     */
    public function redirectNode(EntityInterface $node) {
        $fields = $this->commentManager
            ->getFields('node');
        // Legacy nodes only had a single comment field, so use the first comment
        // field on the entity.
        if (!empty($fields) && ($field_names = array_keys($fields)) && ($field_name = reset($field_names))) {
            return $this->redirect('comment.reply', [
                'entity_type' => 'node',
                'entity' => $node->id(),
                'field_name' => $field_name,
            ]);
        }
        throw new NotFoundHttpException();
    }
    
    /**
     * Form constructor for the comment reply form.
     *
     * There are several cases that have to be handled, including:
     *   - replies to comments
     *   - replies to entities
     *
     * @param \Symfony\Component\HttpFoundation\Request $request
     *   The current request object.
     * @param \Drupal\Core\Entity\EntityInterface $entity
     *   The entity this comment belongs to.
     * @param string $field_name
     *   The field_name to which the comment belongs.
     * @param int $pid
     *   (optional) Some comments are replies to other comments. In those cases,
     *   $pid is the parent comment's comment ID. Defaults to NULL.
     *
     * @return array|\Symfony\Component\HttpFoundation\RedirectResponse
     *   An associative array containing:
     *   - An array for rendering the entity or parent comment.
     *     - comment_entity: If the comment is a reply to the entity.
     *     - comment_parent: If the comment is a reply to another comment.
     *   - comment_form: The comment form as a renderable array.
     *
     * @throws \Symfony\Component\HttpKernel\Exception\NotFoundHttpException
     */
    public function getReplyForm(Request $request, EntityInterface $entity, $field_name, $pid = NULL) {
        $account = $this->currentUser();
        $build = [];
        // The user is not just previewing a comment.
        if ($request->request
            ->get('op') != $this->t('Preview')) {
            // $pid indicates that this is a reply to a comment.
            if ($pid) {
                // Load the parent comment.
                $comment = $this->entityTypeManager()
                    ->getStorage('comment')
                    ->load($pid);
                // Display the parent comment.
                $build['comment_parent'] = $this->entityTypeManager()
                    ->getViewBuilder('comment')
                    ->view($comment);
            }
            elseif ($entity->access('view', $account)) {
                // We make sure the field value isn't set so we don't end up with a
                // redirect loop.
                $entity = clone $entity;
                $entity->{$field_name}->status = CommentItemInterface::HIDDEN;
                // Render array of the entity full view mode.
                $build['commented_entity'] = $this->entityTypeManager()
                    ->getViewBuilder($entity->getEntityTypeId())
                    ->view($entity, 'full');
                unset($build['commented_entity']['#cache']);
            }
        }
        else {
            $build['#title'] = $this->t('Preview comment');
        }
        // Show the actual reply box.
        $comment = $this->entityTypeManager()
            ->getStorage('comment')
            ->create([
            'entity_id' => $entity->id(),
            'pid' => $pid,
            'entity_type' => $entity->getEntityTypeId(),
            'field_name' => $field_name,
        ]);
        $build['comment_form'] = $this->entityFormBuilder()
            ->getForm($comment);
        return $build;
    }
    
    /**
     * Access check for the reply form.
     *
     * @param \Drupal\Core\Entity\EntityInterface $entity
     *   The entity this comment belongs to.
     * @param string $field_name
     *   The field_name to which the comment belongs.
     * @param int $pid
     *   (optional) Some comments are replies to other comments. In those cases,
     *   $pid is the parent comment's comment ID. Defaults to NULL.
     *
     * @return \Drupal\Core\Access\AccessResultInterface
     *   An access result
     *
     * @throws \Symfony\Component\HttpKernel\Exception\NotFoundHttpException
     */
    public function replyFormAccess(EntityInterface $entity, $field_name, $pid = NULL) {
        // Check if entity and field exists.
        $fields = $this->commentManager
            ->getFields($entity->getEntityTypeId());
        if (empty($fields[$field_name])) {
            throw new NotFoundHttpException();
        }
        $account = $this->currentUser();
        // Check if the user has the proper permissions.
        $access = AccessResult::allowedIfHasPermission($account, 'post comments');
        // If commenting is open on the entity.
        $status = $entity->{$field_name}->status;
        $access = $access->andIf(AccessResult::allowedIf($status == CommentItemInterface::OPEN)->addCacheableDependency($entity))
            ->andIf(AccessResult::allowedIf($entity->access('view')));
        // $pid indicates that this is a reply to a comment.
        if ($pid) {
            // Check if the user has the proper permissions.
            $access = $access->andIf(AccessResult::allowedIfHasPermission($account, 'access comments'));
            // Load the parent comment.
            $comment = $this->entityTypeManager()
                ->getStorage('comment')
                ->load($pid);
            // Check if the parent comment is published and belongs to the entity.
            $access = $access->andIf(AccessResult::allowedIf($comment && $comment->isPublished() && $comment->getCommentedEntityId() == $entity->id()));
            if ($comment) {
                $access->addCacheableDependency($comment);
            }
        }
        return $access;
    }
    
    /**
     * Returns a set of nodes' last read timestamps.
     *
     * @param \Symfony\Component\HttpFoundation\Request $request
     *   The request of the page.
     *
     * @return \Symfony\Component\HttpFoundation\JsonResponse
     *   The JSON response.
     *
     * @throws \Symfony\Component\HttpKernel\Exception\AccessDeniedHttpException
     * @throws \Symfony\Component\HttpKernel\Exception\NotFoundHttpException
     */
    public function renderNewCommentsNodeLinks(Request $request) {
        if ($this->currentUser()
            ->isAnonymous()) {
            throw new AccessDeniedHttpException();
        }
        if (!$request->request
            ->has('node_ids') || !$request->request
            ->has('field_name')) {
            throw new NotFoundHttpException();
        }
        $nids = $request->request
            ->all('node_ids');
        $field_name = $request->request
            ->get('field_name');
        // Only handle up to 100 nodes.
        $nids = array_slice($nids, 0, 100);
        $links = [];
        foreach ($nids as $nid) {
            $node = $this->entityTypeManager()
                ->getStorage('node')
                ->load($nid);
            $new = $this->commentManager
                ->getCountNewComments($node);
            $page_number = $this->entityTypeManager()
                ->getStorage('comment')
                ->getNewCommentPageNumber($node->{$field_name}->comment_count, $new, $node, $field_name);
            $query = $page_number ? [
                'page' => $page_number,
            ] : NULL;
            $links[$nid] = [
                'new_comment_count' => (int) $new,
                'first_new_comment_link' => Url::fromRoute('entity.node.canonical', [
                    'node' => $node->id(),
                ], [
                    'query' => $query,
                    'fragment' => 'new',
                ])
                    ->toString(),
            ];
        }
        return new JsonResponse($links);
    }

}