class MediaLibraryUiBuilder

class MediaLibraryUiBuilder {
    use StringTranslationTrait;
    
    /**
     * The form builder.
     *
     * @var \Drupal\Core\Form\FormBuilderInterface
     */
    protected $formBuilder;
    
    /**
     * The entity type manager.
     *
     * @var \Drupal\Core\Entity\EntityTypeManagerInterface
     */
    protected $entityTypeManager;
    
    /**
     * The currently active request object.
     *
     * @var \Symfony\Component\HttpFoundation\Request
     */
    protected $request;
    
    /**
     * The views executable factory.
     *
     * @var \Drupal\views\ViewExecutableFactory
     */
    protected $viewsExecutableFactory;
    
    /**
     * The media library opener resolver.
     *
     * @var \Drupal\media_library\OpenerResolverInterface
     */
    protected $openerResolver;
    
    /**
     * Constructs a MediaLibraryUiBuilder instance.
     *
     * @param \Drupal\Core\Entity\EntityTypeManagerInterface $entity_type_manager
     *   The entity type manager.
     * @param \Symfony\Component\HttpFoundation\RequestStack $request_stack
     *   The request stack.
     * @param \Drupal\views\ViewExecutableFactory $views_executable_factory
     *   The views executable factory.
     * @param \Drupal\Core\Form\FormBuilderInterface $form_builder
     *   The currently active request object.
     * @param \Drupal\media_library\OpenerResolverInterface $opener_resolver
     *   The opener resolver.
     */
    public function __construct(EntityTypeManagerInterface $entity_type_manager, RequestStack $request_stack, ViewExecutableFactory $views_executable_factory, FormBuilderInterface $form_builder, OpenerResolverInterface $opener_resolver) {
        $this->entityTypeManager = $entity_type_manager;
        $this->request = $request_stack->getCurrentRequest();
        $this->viewsExecutableFactory = $views_executable_factory;
        $this->formBuilder = $form_builder;
        $this->openerResolver = $opener_resolver;
    }
    
    /**
     * Get media library dialog options.
     *
     * @return array
     *   The media library dialog options.
     */
    public static function dialogOptions() {
        return [
            'classes' => [
                'ui-dialog' => 'media-library-widget-modal',
            ],
            'title' => t('Add or select media'),
            'height' => '75%',
            'width' => '75%',
        ];
    }
    
    /**
     * Build the media library UI.
     *
     * @param \Drupal\media_library\MediaLibraryState $state
     *   (optional) The current state of the media library, derived from the
     *   current request.
     *
     * @return array
     *   The render array for the media library.
     */
    public function buildUi(?MediaLibraryState $state = NULL) {
        if (!$state) {
            $state = MediaLibraryState::fromRequest($this->request);
        }
        // When navigating to a media type through the vertical tabs, we only want
        // to load the changed library content. This is not only more efficient, but
        // also provides a more accessible user experience for screen readers.
        if ($state->get('media_library_content') === '1') {
            return $this->buildLibraryContent($state);
        }
        else {
            return [
                '#theme' => 'media_library_wrapper',
                '#attributes' => [
                    'id' => 'media-library-wrapper',
                ],
                'menu' => $this->buildMediaTypeMenu($state),
                'content' => $this->buildLibraryContent($state),
                // Attach the JavaScript for the media library UI. The number of
                // available slots needs to be added to make sure users can't select
                // more items than allowed.
'#attached' => [
                    'library' => [
                        'media_library/ui',
                    ],
                    'drupalSettings' => [
                        'media_library' => [
                            'selection_remaining' => $state->getAvailableSlots(),
                        ],
                    ],
                ],
            ];
        }
    }
    
    /**
     * Build the media library content area.
     *
     * @param \Drupal\media_library\MediaLibraryState $state
     *   The current state of the media library, derived from the current request.
     *
     * @return array
     *   The render array for the media library.
     */
    protected function buildLibraryContent(MediaLibraryState $state) {
        return [
            '#type' => 'container',
            '#theme_wrappers' => [
                'container__media_library_content',
            ],
            '#attributes' => [
                'id' => 'media-library-content',
            ],
            'form' => $this->buildMediaTypeAddForm($state),
            'view' => $this->buildMediaLibraryView($state),
        ];
    }
    
    /**
     * Check access to the media library.
     *
     * @param \Drupal\Core\Session\AccountInterface $account
     *   Run access checks for this account.
     * @param \Drupal\media_library\MediaLibraryState $state
     *   (optional) The current state of the media library, derived from the
     *   current request.
     *
     * @return \Drupal\Core\Access\AccessResult
     *   The access result.
     */
    public function checkAccess(AccountInterface $account, ?MediaLibraryState $state = NULL) {
        if (!$state) {
            try {
                $state = MediaLibraryState::fromRequest($this->request);
            } catch (BadRequestHttpException $e) {
                return AccessResult::forbidden($e->getMessage());
            } catch (\InvalidArgumentException $e) {
                return AccessResult::forbidden($e->getMessage());
            }
        }
        // Deny access if the view or display are removed.
        $view = $this->entityTypeManager
            ->getStorage('view')
            ->load('media_library');
        if (!$view) {
            return AccessResult::forbidden('The media library view does not exist.')->setCacheMaxAge(0);
        }
        if (!$view->getDisplay('widget')) {
            return AccessResult::forbidden('The media library widget display does not exist.')->addCacheableDependency($view);
        }
        // The user must at least be able to view media in order to access the media
        // library.
        $can_view_media = AccessResult::allowedIfHasPermission($account, 'view media')->addCacheableDependency($view);
        // Delegate any further access checking to the opener service nominated by
        // the media library state.
        return $this->openerResolver
            ->get($state)
            ->checkAccess($state, $account)
            ->andIf($can_view_media);
    }
    
    /**
     * Get the media type menu for the media library.
     *
     * @param \Drupal\media_library\MediaLibraryState $state
     *   The current state of the media library, derived from the current request.
     *
     * @return array
     *   The render array for the media type menu.
     */
    protected function buildMediaTypeMenu(MediaLibraryState $state) {
        // Add the menu for each type if we have more than 1 media type enabled for
        // the field.
        $allowed_type_ids = $state->getAllowedTypeIds();
        if (count($allowed_type_ids) <= 1) {
            return [];
        }
        // @todo Add a class to the li element.
        //   https://www.drupal.org/project/drupal/issues/3029227
        $menu = [
            '#theme' => 'links__media_library_menu',
            '#links' => [],
            '#attributes' => [
                'class' => [
                    'js-media-library-menu',
                ],
            ],
        ];
        $allowed_types = $this->entityTypeManager
            ->getStorage('media_type')
            ->loadMultiple($allowed_type_ids);
        $selected_type_id = $state->getSelectedTypeId();
        foreach ($allowed_types as $allowed_type_id => $allowed_type) {
            $link_state = MediaLibraryState::create($state->getOpenerId(), $state->getAllowedTypeIds(), $allowed_type_id, $state->getAvailableSlots(), $state->getOpenerParameters());
            // Add the 'media_library_content' parameter so the response will contain
            // only the updated content for the tab.
            // @see self::buildUi()
            $link_state->set('media_library_content', 1);
            $title = $allowed_type->label();
            $display_title = [
                '#markup' => $this->t('<span class="visually-hidden">Show </span>@title<span class="visually-hidden"> media</span>', [
                    '@title' => $title,
                ]),
            ];
            if ($allowed_type_id === $selected_type_id) {
                $display_title = [
                    '#markup' => $this->t('<span class="visually-hidden">Show </span>@title<span class="visually-hidden"> media</span><span class="active-tab visually-hidden"> (selected)</span>', [
                        '@title' => $title,
                    ]),
                ];
            }
            $menu['#links']['media-library-menu-' . $allowed_type_id] = [
                'title' => $display_title,
                'url' => Url::fromRoute('media_library.ui', [], [
                    'query' => $link_state->all(),
                ]),
                'attributes' => [
                    'role' => 'button',
                    'data-title' => $title,
                ],
            ];
        }
        // Set the active menu item.
        $menu['#links']['media-library-menu-' . $selected_type_id]['attributes']['class'][] = 'active';
        return $menu;
    }
    
    /**
     * Get the add form for the selected media type.
     *
     * @param \Drupal\media_library\MediaLibraryState $state
     *   The current state of the media library, derived from the current request.
     *
     * @return array
     *   The render array for the media type add form.
     */
    protected function buildMediaTypeAddForm(MediaLibraryState $state) {
        $selected_type_id = $state->getSelectedTypeId();
        $access_handler = $this->entityTypeManager
            ->getAccessControlHandler('media');
        $context = [
            'media_library_state' => $state,
        ];
        if (!$access_handler->createAccess($selected_type_id, NULL, $context)) {
            return [];
        }
        $selected_type = $this->entityTypeManager
            ->getStorage('media_type')
            ->load($selected_type_id);
        $plugin_definition = $selected_type->getSource()
            ->getPluginDefinition();
        if (empty($plugin_definition['forms']['media_library_add'])) {
            return [];
        }
        // After the form to add new media is submitted, we need to rebuild the
        // media library with a new instance of the media add form. The form API
        // allows us to do that by forcing empty user input.
        // @see \Drupal\Core\Form\FormBuilder::doBuildForm()
        $form_state = new FormState();
        if ($state->get('_media_library_form_rebuild')) {
            $form_state->setUserInput([]);
            $state->remove('_media_library_form_rebuild');
        }
        $form_state->set('media_library_state', $state);
        return $this->formBuilder
            ->buildForm($plugin_definition['forms']['media_library_add'], $form_state);
    }
    
    /**
     * Get the media library view.
     *
     * @param \Drupal\media_library\MediaLibraryState $state
     *   The current state of the media library, derived from the current request.
     *
     * @return array
     *   The render array for the media library view.
     */
    protected function buildMediaLibraryView(MediaLibraryState $state) {
        // @todo Make the view configurable in
        //   https://www.drupal.org/project/drupal/issues/2971209
        $view = $this->entityTypeManager
            ->getStorage('view')
            ->load('media_library');
        $view_executable = $this->viewsExecutableFactory
            ->get($view);
        $display_id = $state->get('views_display_id', 'widget');
        // Make sure the state parameters are set in the request so the view can
        // pass the parameters along in the pager, filters etc.
        $view_request = $view_executable->getRequest();
        $view_request->query
            ->add($state->all());
        $view_executable->setRequest($view_request);
        $args = [
            $state->getSelectedTypeId(),
        ];
        $view_executable->setDisplay($display_id);
        $view_executable->preExecute($args);
        $view_executable->execute($display_id);
        return $view_executable->buildRenderable($display_id, $args, FALSE);
    }

}