class DefaultHtmlRouteProvider

class DefaultHtmlRouteProvider implements EntityRouteProviderInterface, EntityHandlerInterface {
    
    /**
     * The entity type manager.
     *
     * @var \Drupal\Core\Entity\EntityTypeManagerInterface
     */
    protected $entityTypeManager;
    
    /**
     * The entity field manager.
     *
     * @var \Drupal\Core\Entity\EntityFieldManagerInterface
     */
    protected $entityFieldManager;
    
    /**
     * Constructs a new DefaultHtmlRouteProvider.
     *
     * @param \Drupal\Core\Entity\EntityTypeManagerInterface $entity_type_manager
     *   The entity type manager.
     * @param \Drupal\Core\Entity\EntityFieldManagerInterface $entity_field_manager
     *   The entity field manager.
     */
    public function __construct(EntityTypeManagerInterface $entity_type_manager, EntityFieldManagerInterface $entity_field_manager) {
        $this->entityTypeManager = $entity_type_manager;
        $this->entityFieldManager = $entity_field_manager;
    }
    
    /**
     * {@inheritdoc}
     */
    public static function createInstance(ContainerInterface $container, EntityTypeInterface $entity_type) {
        return new static($container->get('entity_type.manager'), $container->get('entity_field.manager'));
    }
    
    /**
     * {@inheritdoc}
     */
    public function getRoutes(EntityTypeInterface $entity_type) {
        $collection = new RouteCollection();
        $entity_type_id = $entity_type->id();
        if ($add_page_route = $this->getAddPageRoute($entity_type)) {
            $collection->add("entity.{$entity_type_id}.add_page", $add_page_route);
        }
        if ($add_form_route = $this->getAddFormRoute($entity_type)) {
            $collection->add("entity.{$entity_type_id}.add_form", $add_form_route);
        }
        if ($canonical_route = $this->getCanonicalRoute($entity_type)) {
            $collection->add("entity.{$entity_type_id}.canonical", $canonical_route);
        }
        if ($edit_route = $this->getEditFormRoute($entity_type)) {
            $collection->add("entity.{$entity_type_id}.edit_form", $edit_route);
        }
        if ($delete_route = $this->getDeleteFormRoute($entity_type)) {
            $collection->add("entity.{$entity_type_id}.delete_form", $delete_route);
        }
        if ($collection_route = $this->getCollectionRoute($entity_type)) {
            $collection->add("entity.{$entity_type_id}.collection", $collection_route);
        }
        if ($delete_multiple_route = $this->getDeleteMultipleFormRoute($entity_type)) {
            $collection->add('entity.' . $entity_type->id() . '.delete_multiple_form', $delete_multiple_route);
        }
        return $collection;
    }
    
    /**
     * Gets the add page route.
     *
     * Built only for entity types that have bundles.
     *
     * @param \Drupal\Core\Entity\EntityTypeInterface $entity_type
     *   The entity type.
     *
     * @return \Symfony\Component\Routing\Route|null
     *   The generated route, if available.
     */
    protected function getAddPageRoute(EntityTypeInterface $entity_type) {
        if ($entity_type->hasLinkTemplate('add-page') && $entity_type->getKey('bundle')) {
            $route = new Route($entity_type->getLinkTemplate('add-page'));
            $route->setDefault('_controller', EntityController::class . '::addPage');
            $route->setDefault('_title_callback', EntityController::class . '::addTitle');
            $route->setDefault('entity_type_id', $entity_type->id());
            $route->setRequirement('_entity_create_any_access', $entity_type->id());
            return $route;
        }
    }
    
    /**
     * Gets the add-form route.
     *
     * @param \Drupal\Core\Entity\EntityTypeInterface $entity_type
     *   The entity type.
     *
     * @return \Symfony\Component\Routing\Route|null
     *   The generated route, if available.
     */
    protected function getAddFormRoute(EntityTypeInterface $entity_type) {
        if ($entity_type->hasLinkTemplate('add-form')) {
            $entity_type_id = $entity_type->id();
            $route = new Route($entity_type->getLinkTemplate('add-form'));
            // Use the add form handler, if available, otherwise default.
            $operation = 'default';
            if ($entity_type->getFormClass('add')) {
                $operation = 'add';
            }
            $route->setDefaults([
                '_entity_form' => "{$entity_type_id}.{$operation}",
                'entity_type_id' => $entity_type_id,
            ]);
            // If the entity has bundles, we can provide a bundle-specific title
            // and access requirements.
            $expected_parameter = $entity_type->getBundleEntityType() ?: $entity_type->getKey('bundle');
            // @todo We have to check if a route contains a bundle in its path as
            //   test entities have inconsistent usage of "add-form" link templates.
            //   Fix it in https://www.drupal.org/node/2699959.
            if (($bundle_key = $entity_type->getKey('bundle')) && strpos($route->getPath(), '{' . $expected_parameter . '}') !== FALSE) {
                $route->setDefault('_title_callback', EntityController::class . '::addBundleTitle');
                // If the bundles are entities themselves, we can add parameter
                // information to the route options.
                if ($bundle_entity_type_id = $entity_type->getBundleEntityType()) {
                    $bundle_entity_type = $this->entityTypeManager
                        ->getDefinition($bundle_entity_type_id);
                    $route->setDefault('bundle_parameter', $bundle_entity_type_id)
                        ->setRequirement('_entity_create_access', $entity_type_id . ':{' . $bundle_entity_type_id . '}');
                    // Entity types with serial IDs can specify this in their route
                    // requirements, improving the matching process.
                    if ($this->getEntityTypeIdKeyType($bundle_entity_type) === 'integer') {
                        $route->setRequirement($entity_type_id, '\\d+');
                    }
                    $bundle_entity_parameter = [
                        'type' => 'entity:' . $bundle_entity_type_id,
                    ];
                    if ($bundle_entity_type instanceof ConfigEntityTypeInterface) {
                        // The add page might be displayed on an admin path. Even then, we
                        // need to load configuration overrides so that, for example, the
                        // bundle label gets translated correctly.
                        // @see \Drupal\Core\ParamConverter\AdminPathConfigEntityConverter
                        $bundle_entity_parameter['with_config_overrides'] = TRUE;
                    }
                    $route->setOption('parameters', [
                        $bundle_entity_type_id => $bundle_entity_parameter,
                    ]);
                }
                else {
                    // If the bundles are not entities, the bundle key is used as the
                    // route parameter name directly.
                    $route->setDefault('bundle_parameter', $bundle_key)
                        ->setRequirement('_entity_create_access', $entity_type_id . ':{' . $bundle_key . '}');
                }
            }
            else {
                $route->setDefault('_title_callback', EntityController::class . '::addTitle')
                    ->setRequirement('_entity_create_access', $entity_type_id);
            }
            return $route;
        }
    }
    
    /**
     * Gets the canonical route.
     *
     * @param \Drupal\Core\Entity\EntityTypeInterface $entity_type
     *   The entity type.
     *
     * @return \Symfony\Component\Routing\Route|null
     *   The generated route, if available.
     */
    protected function getCanonicalRoute(EntityTypeInterface $entity_type) {
        if ($entity_type->hasLinkTemplate('canonical') && $entity_type->hasViewBuilderClass()) {
            $entity_type_id = $entity_type->id();
            $route = new Route($entity_type->getLinkTemplate('canonical'));
            $route->addDefaults([
                '_entity_view' => "{$entity_type_id}.full",
                '_title_callback' => '\\Drupal\\Core\\Entity\\Controller\\EntityController::title',
            ])
                ->setRequirement('_entity_access', "{$entity_type_id}.view")
                ->setOption('parameters', [
                $entity_type_id => [
                    'type' => 'entity:' . $entity_type_id,
                ],
            ]);
            // Entity types with serial IDs can specify this in their route
            // requirements, improving the matching process.
            if ($this->getEntityTypeIdKeyType($entity_type) === 'integer') {
                $route->setRequirement($entity_type_id, '\\d+');
            }
            return $route;
        }
    }
    
    /**
     * Gets the edit-form route.
     *
     * @param \Drupal\Core\Entity\EntityTypeInterface $entity_type
     *   The entity type.
     *
     * @return \Symfony\Component\Routing\Route|null
     *   The generated route, if available.
     */
    protected function getEditFormRoute(EntityTypeInterface $entity_type) {
        if ($entity_type->hasLinkTemplate('edit-form')) {
            $entity_type_id = $entity_type->id();
            $route = new Route($entity_type->getLinkTemplate('edit-form'));
            // Use the edit form handler, if available, otherwise default.
            $operation = 'default';
            if ($entity_type->getFormClass('edit')) {
                $operation = 'edit';
            }
            $route->setDefaults([
                '_entity_form' => "{$entity_type_id}.{$operation}",
                '_title_callback' => '\\Drupal\\Core\\Entity\\Controller\\EntityController::editTitle',
            ])
                ->setRequirement('_entity_access', "{$entity_type_id}.update")
                ->setOption('parameters', [
                $entity_type_id => [
                    'type' => 'entity:' . $entity_type_id,
                ],
            ]);
            // Entity types with serial IDs can specify this in their route
            // requirements, improving the matching process.
            if ($this->getEntityTypeIdKeyType($entity_type) === 'integer') {
                $route->setRequirement($entity_type_id, '\\d+');
            }
            return $route;
        }
    }
    
    /**
     * Gets the delete-form route.
     *
     * @param \Drupal\Core\Entity\EntityTypeInterface $entity_type
     *   The entity type.
     *
     * @return \Symfony\Component\Routing\Route|null
     *   The generated route, if available.
     */
    protected function getDeleteFormRoute(EntityTypeInterface $entity_type) {
        if ($entity_type->hasLinkTemplate('delete-form')) {
            $entity_type_id = $entity_type->id();
            $route = new Route($entity_type->getLinkTemplate('delete-form'));
            $route->addDefaults([
                '_entity_form' => "{$entity_type_id}.delete",
                '_title_callback' => '\\Drupal\\Core\\Entity\\Controller\\EntityController::deleteTitle',
            ])
                ->setRequirement('_entity_access', "{$entity_type_id}.delete")
                ->setOption('parameters', [
                $entity_type_id => [
                    'type' => 'entity:' . $entity_type_id,
                ],
            ]);
            // Entity types with serial IDs can specify this in their route
            // requirements, improving the matching process.
            if ($this->getEntityTypeIdKeyType($entity_type) === 'integer') {
                $route->setRequirement($entity_type_id, '\\d+');
            }
            return $route;
        }
    }
    
    /**
     * Gets the collection route.
     *
     * @param \Drupal\Core\Entity\EntityTypeInterface $entity_type
     *   The entity type.
     *
     * @return \Symfony\Component\Routing\Route|null
     *   The generated route, if available.
     */
    protected function getCollectionRoute(EntityTypeInterface $entity_type) {
        // If the entity type does not provide an admin permission, there is no way
        // to control access, so we cannot provide a route in a sensible way.
        if ($entity_type->hasLinkTemplate('collection') && $entity_type->hasListBuilderClass() && ($admin_permission = $entity_type->getAdminPermission())) {
            
            /** @var \Drupal\Core\StringTranslation\TranslatableMarkup $label */
            $label = $entity_type->getCollectionLabel();
            $route = new Route($entity_type->getLinkTemplate('collection'));
            $route->addDefaults([
                '_entity_list' => $entity_type->id(),
                '_title' => $label->getUntranslatedString(),
                '_title_arguments' => $label->getArguments(),
                '_title_context' => $label->getOption('context'),
            ])
                ->setRequirement('_permission', $admin_permission);
            return $route;
        }
    }
    
    /**
     * Gets the type of the ID key for a given entity type.
     *
     * @param \Drupal\Core\Entity\EntityTypeInterface $entity_type
     *   An entity type.
     *
     * @return string|null
     *   The type of the ID key for a given entity type, or NULL if the entity
     *   type does not support fields.
     */
    protected function getEntityTypeIdKeyType(EntityTypeInterface $entity_type) {
        if (!$entity_type->entityClassImplements(FieldableEntityInterface::class)) {
            return NULL;
        }
        $field_storage_definitions = $this->entityFieldManager
            ->getFieldStorageDefinitions($entity_type->id());
        return $field_storage_definitions[$entity_type->getKey('id')]
            ->getType();
    }
    
    /**
     * Returns the delete multiple form route.
     *
     * @param \Drupal\Core\Entity\EntityTypeInterface $entity_type
     *   The entity type.
     *
     * @return \Symfony\Component\Routing\Route|null
     *   The generated route, if available.
     */
    protected function getDeleteMultipleFormRoute(EntityTypeInterface $entity_type) {
        if ($entity_type->hasLinkTemplate('delete-multiple-form') && $entity_type->hasHandlerClass('form', 'delete-multiple-confirm')) {
            $route = new Route($entity_type->getLinkTemplate('delete-multiple-form'));
            $route->setDefault('_form', $entity_type->getFormClass('delete-multiple-confirm'));
            $route->setDefault('entity_type_id', $entity_type->id());
            $route->setRequirement('_entity_delete_multiple_access', $entity_type->id());
            return $route;
        }
    }

}