class Routes

class Routes implements ContainerInjectionInterface {
    
    /**
     * The service name for the primary JSON:API controller.
     *
     * All resources except the entrypoint are served by this controller.
     *
     * @var string
     */
    const CONTROLLER_SERVICE_NAME = 'jsonapi.entity_resource';
    
    /**
     * A key with which to flag a route as belonging to the JSON:API module.
     *
     * @var string
     */
    const JSON_API_ROUTE_FLAG_KEY = '_is_jsonapi';
    
    /**
     * The route default key for the route's resource type information.
     *
     * @var string
     */
    const RESOURCE_TYPE_KEY = 'resource_type';
    
    /**
     * The JSON:API resource type repository.
     *
     * @var \Drupal\jsonapi\ResourceType\ResourceTypeRepositoryInterface
     */
    protected $resourceTypeRepository;
    
    /**
     * List of providers.
     *
     * @var string[]
     */
    protected $providerIds;
    
    /**
     * The JSON:API base path.
     *
     * @var string
     */
    protected $jsonApiBasePath;
    
    /**
     * Instantiates a Routes object.
     *
     * @param \Drupal\jsonapi\ResourceType\ResourceTypeRepositoryInterface $resource_type_repository
     *   The JSON:API resource type repository.
     * @param string[] $authentication_providers
     *   The authentication providers, keyed by ID.
     * @param string $jsonapi_base_path
     *   The JSON:API base path.
     */
    public function __construct(ResourceTypeRepositoryInterface $resource_type_repository, array $authentication_providers, $jsonapi_base_path) {
        $this->resourceTypeRepository = $resource_type_repository;
        $this->providerIds = array_keys($authentication_providers);
        assert(is_string($jsonapi_base_path));
        assert($jsonapi_base_path[0] === '/', sprintf('The provided base path should contain a leading slash "/". Given: "%s".', $jsonapi_base_path));
        assert(substr($jsonapi_base_path, -1) !== '/', sprintf('The provided base path should not contain a trailing slash "/". Given: "%s".', $jsonapi_base_path));
        $this->jsonApiBasePath = $jsonapi_base_path;
    }
    
    /**
     * {@inheritdoc}
     */
    public static function create(ContainerInterface $container) {
        return new static($container->get('jsonapi.resource_type.repository'), $container->getParameter('authentication_providers'), $container->getParameter('jsonapi.base_path'));
    }
    
    /**
     * {@inheritdoc}
     */
    public function routes() {
        $routes = new RouteCollection();
        $upload_routes = new RouteCollection();
        // JSON:API's routes: entry point + routes for every resource type.
        foreach ($this->resourceTypeRepository
            ->all() as $resource_type) {
            $routes->addCollection(static::getRoutesForResourceType($resource_type, $this->jsonApiBasePath));
            $upload_routes->addCollection(static::getFileUploadRoutesForResourceType($resource_type, $this->jsonApiBasePath));
        }
        $routes->add('jsonapi.resource_list', static::getEntryPointRoute($this->jsonApiBasePath));
        // Require the JSON:API media type header on every route, except on file
        // upload routes, where we require `application/octet-stream`.
        $routes->addRequirements([
            '_content_type_format' => 'api_json',
        ]);
        $upload_routes->addRequirements([
            '_content_type_format' => 'bin',
        ]);
        $routes->addCollection($upload_routes);
        // Enable all available authentication providers.
        $routes->addOptions([
            '_auth' => $this->providerIds,
        ]);
        // Flag every route as belonging to the JSON:API module.
        $routes->addDefaults([
            static::JSON_API_ROUTE_FLAG_KEY => TRUE,
        ]);
        // All routes serve only the JSON:API media type.
        $routes->addRequirements([
            '_format' => 'api_json',
        ]);
        return $routes;
    }
    
    /**
     * Gets applicable resource routes for a JSON:API resource type.
     *
     * @param \Drupal\jsonapi\ResourceType\ResourceType $resource_type
     *   The JSON:API resource type for which to get the routes.
     * @param string $path_prefix
     *   The root path prefix.
     *
     * @return \Symfony\Component\Routing\RouteCollection
     *   A collection of routes for the given resource type.
     */
    protected static function getRoutesForResourceType(ResourceType $resource_type, $path_prefix) {
        // Internal resources have no routes.
        if ($resource_type->isInternal()) {
            return new RouteCollection();
        }
        $routes = new RouteCollection();
        // Collection route like `/jsonapi/node/article`.
        if ($resource_type->isLocatable()) {
            $collection_route = new Route("/{$resource_type->getPath()}");
            $collection_route->addDefaults([
                RouteObjectInterface::CONTROLLER_NAME => static::CONTROLLER_SERVICE_NAME . ':getCollection',
            ]);
            $collection_route->setMethods([
                'GET',
            ]);
            // Allow anybody access because "view" and "view label" access are checked
            // in the controller.
            $collection_route->setRequirement('_access', 'TRUE');
            $routes->add(static::getRouteName($resource_type, 'collection'), $collection_route);
        }
        // Creation route.
        if ($resource_type->isMutable()) {
            $collection_create_route = new Route("/{$resource_type->getPath()}");
            $collection_create_route->addDefaults([
                RouteObjectInterface::CONTROLLER_NAME => static::CONTROLLER_SERVICE_NAME . ':createIndividual',
            ]);
            $collection_create_route->setMethods([
                'POST',
            ]);
            $create_requirement = sprintf("%s:%s", $resource_type->getEntityTypeId(), $resource_type->getBundle());
            $collection_create_route->setRequirement('_entity_create_access', $create_requirement);
            $collection_create_route->setRequirement('_csrf_request_header_token', 'TRUE');
            $routes->add(static::getRouteName($resource_type, 'collection.post'), $collection_create_route);
        }
        // Individual routes like `/jsonapi/node/article/{uuid}` or
        // `/jsonapi/node/article/{uuid}/relationships/uid`.
        $routes->addCollection(static::getIndividualRoutesForResourceType($resource_type));
        // Add the resource type as a parameter to every resource route.
        foreach ($routes as $route) {
            static::addRouteParameter($route, static::RESOURCE_TYPE_KEY, [
                'type' => ResourceTypeConverter::PARAM_TYPE_ID,
            ]);
            $route->addDefaults([
                static::RESOURCE_TYPE_KEY => $resource_type->getTypeName(),
            ]);
        }
        // Resource routes all have the same base path.
        $routes->addPrefix($path_prefix);
        return $routes;
    }
    
    /**
     * Gets the file upload route collection for the given resource type.
     *
     * @param \Drupal\jsonapi\ResourceType\ResourceType $resource_type
     *   The resource type for which the route collection should be created.
     * @param string $path_prefix
     *   The root path prefix.
     *
     * @return \Symfony\Component\Routing\RouteCollection
     *   The route collection.
     */
    protected static function getFileUploadRoutesForResourceType(ResourceType $resource_type, $path_prefix) {
        $routes = new RouteCollection();
        // Internal resources have no routes; individual routes require locations.
        if ($resource_type->isInternal() || !$resource_type->isLocatable()) {
            return $routes;
        }
        // File upload routes are only necessary for resource types that have file
        // fields.
        $has_file_field = array_reduce($resource_type->getRelatableResourceTypes(), function ($carry, array $target_resource_types) {
            return $carry || static::hasNonInternalFileTargetResourceTypes($target_resource_types);
        }, FALSE);
        if (!$has_file_field) {
            return $routes;
        }
        if ($resource_type->isMutable()) {
            $path = $resource_type->getPath();
            $entity_type_id = $resource_type->getEntityTypeId();
            $new_resource_file_upload_route = new Route("/{$path}/{file_field_name}");
            $new_resource_file_upload_route->addDefaults([
                RouteObjectInterface::CONTROLLER_NAME => 'jsonapi.file_upload:handleFileUploadForNewResource',
            ]);
            $new_resource_file_upload_route->setMethods([
                'POST',
            ]);
            $new_resource_file_upload_route->setRequirement('_csrf_request_header_token', 'TRUE');
            $routes->add(static::getFileUploadRouteName($resource_type, 'new_resource'), $new_resource_file_upload_route);
            $existing_resource_file_upload_route = new Route("/{$path}/{entity}/{file_field_name}");
            $existing_resource_file_upload_route->addDefaults([
                RouteObjectInterface::CONTROLLER_NAME => 'jsonapi.file_upload:handleFileUploadForExistingResource',
            ]);
            $existing_resource_file_upload_route->setMethods([
                'POST',
            ]);
            $existing_resource_file_upload_route->setRequirement('_csrf_request_header_token', 'TRUE');
            $routes->add(static::getFileUploadRouteName($resource_type, 'existing_resource'), $existing_resource_file_upload_route);
            // Add entity parameter conversion to every route.
            $routes->addOptions([
                'parameters' => [
                    'entity' => [
                        'type' => 'entity:' . $entity_type_id,
                    ],
                ],
            ]);
            // Add the resource type as a parameter to every resource route.
            foreach ($routes as $route) {
                static::addRouteParameter($route, static::RESOURCE_TYPE_KEY, [
                    'type' => ResourceTypeConverter::PARAM_TYPE_ID,
                ]);
                $route->addDefaults([
                    static::RESOURCE_TYPE_KEY => $resource_type->getTypeName(),
                ]);
            }
        }
        // File upload routes all have the same base path.
        $routes->addPrefix($path_prefix);
        return $routes;
    }
    
    /**
     * Determines if the given request is for a JSON:API generated route.
     *
     * @param array $defaults
     *   The request's route defaults.
     *
     * @return bool
     *   Whether the request targets a generated route.
     */
    public static function isJsonApiRequest(array $defaults) {
        return isset($defaults[RouteObjectInterface::CONTROLLER_NAME]) && strpos($defaults[RouteObjectInterface::CONTROLLER_NAME], static::CONTROLLER_SERVICE_NAME) === 0;
    }
    
    /**
     * Gets a route collection for the given resource type.
     *
     * @param \Drupal\jsonapi\ResourceType\ResourceType $resource_type
     *   The resource type for which the route collection should be created.
     *
     * @return \Symfony\Component\Routing\RouteCollection
     *   The route collection.
     */
    protected static function getIndividualRoutesForResourceType(ResourceType $resource_type) {
        if (!$resource_type->isLocatable()) {
            return new RouteCollection();
        }
        $routes = new RouteCollection();
        $path = $resource_type->getPath();
        $entity_type_id = $resource_type->getEntityTypeId();
        // Individual read, update and remove.
        $individual_route = new Route("/{$path}/{entity}");
        $individual_route->addDefaults([
            RouteObjectInterface::CONTROLLER_NAME => static::CONTROLLER_SERVICE_NAME . ':getIndividual',
        ]);
        $individual_route->setMethods([
            'GET',
        ]);
        // No _entity_access requirement because "view" and "view label" access are
        // checked in the controller. So it's safe to allow anybody access.
        $individual_route->setRequirement('_access', 'TRUE');
        $routes->add(static::getRouteName($resource_type, 'individual'), $individual_route);
        if ($resource_type->isMutable()) {
            $individual_update_route = new Route($individual_route->getPath());
            $individual_update_route->addDefaults([
                RouteObjectInterface::CONTROLLER_NAME => static::CONTROLLER_SERVICE_NAME . ':patchIndividual',
            ]);
            $individual_update_route->setMethods([
                'PATCH',
            ]);
            $individual_update_route->setRequirement('_entity_access', "entity.update");
            $individual_update_route->setRequirement('_csrf_request_header_token', 'TRUE');
            $routes->add(static::getRouteName($resource_type, 'individual.patch'), $individual_update_route);
            $individual_remove_route = new Route($individual_route->getPath());
            $individual_remove_route->addDefaults([
                RouteObjectInterface::CONTROLLER_NAME => static::CONTROLLER_SERVICE_NAME . ':deleteIndividual',
            ]);
            $individual_remove_route->setMethods([
                'DELETE',
            ]);
            $individual_remove_route->setRequirement('_entity_access', "entity.delete");
            $individual_remove_route->setRequirement('_csrf_request_header_token', 'TRUE');
            $routes->add(static::getRouteName($resource_type, 'individual.delete'), $individual_remove_route);
        }
        foreach ($resource_type->getRelatableResourceTypes() as $relationship_field_name => $target_resource_types) {
            // Read, update, add, or remove an individual resources relationships to
            // other resources.
            $relationship_route = new Route("/{$path}/{entity}/relationships/{$relationship_field_name}");
            $relationship_route->addDefaults([
                '_on_relationship' => TRUE,
            ]);
            $relationship_route->addDefaults([
                'related' => $relationship_field_name,
            ]);
            $relationship_route->setRequirement('_csrf_request_header_token', 'TRUE');
            $relationship_route_methods = $resource_type->isMutable() ? [
                'GET',
                'POST',
                'PATCH',
                'DELETE',
            ] : [
                'GET',
            ];
            $relationship_controller_methods = [
                'GET' => 'getRelationship',
                'POST' => 'addToRelationshipData',
                'PATCH' => 'replaceRelationshipData',
                'DELETE' => 'removeFromRelationshipData',
            ];
            foreach ($relationship_route_methods as $method) {
                $method_specific_relationship_route = clone $relationship_route;
                $field_operation = $method === 'GET' ? 'view' : 'edit';
                $method_specific_relationship_route->setRequirement(RelationshipRouteAccessCheck::ROUTE_REQUIREMENT_KEY, "{$relationship_field_name}.{$field_operation}");
                $method_specific_relationship_route->addDefaults([
                    RouteObjectInterface::CONTROLLER_NAME => static::CONTROLLER_SERVICE_NAME . ":{$relationship_controller_methods[$method]}",
                ]);
                $method_specific_relationship_route->setMethods($method);
                $routes->add(static::getRouteName($resource_type, sprintf("%s.relationship.%s", $relationship_field_name, strtolower($method))), $method_specific_relationship_route);
            }
            // Only create routes for related routes that target at least one
            // non-internal resource type.
            if (static::hasNonInternalTargetResourceTypes($target_resource_types)) {
                // Get an individual resource's related resources.
                $related_route = new Route("/{$path}/{entity}/{$relationship_field_name}");
                $related_route->setMethods([
                    'GET',
                ]);
                $related_route->addDefaults([
                    RouteObjectInterface::CONTROLLER_NAME => static::CONTROLLER_SERVICE_NAME . ':getRelated',
                ]);
                $related_route->addDefaults([
                    'related' => $relationship_field_name,
                ]);
                $related_route->setRequirement(RelationshipRouteAccessCheck::ROUTE_REQUIREMENT_KEY, "{$relationship_field_name}.view");
                $routes->add(static::getRouteName($resource_type, "{$relationship_field_name}.related"), $related_route);
            }
        }
        // Add entity parameter conversion to every route.
        $routes->addOptions([
            'parameters' => [
                'entity' => [
                    'type' => 'entity:' . $entity_type_id,
                ],
            ],
        ]);
        return $routes;
    }
    
    /**
     * Provides the entry point route.
     *
     * @param string $path_prefix
     *   The root path prefix.
     *
     * @return \Symfony\Component\Routing\Route
     *   The entry point route.
     */
    protected function getEntryPointRoute($path_prefix) {
        $entry_point = new Route("/{$path_prefix}");
        $entry_point->addDefaults([
            RouteObjectInterface::CONTROLLER_NAME => EntryPoint::class . '::index',
        ]);
        $entry_point->setRequirement('_access', 'TRUE');
        $entry_point->setMethods([
            'GET',
        ]);
        return $entry_point;
    }
    
    /**
     * Adds a parameter option to a route, overrides options of the same name.
     *
     * The Symfony Route class only has a method for adding options which
     * overrides any previous values. Therefore, it is tedious to add a single
     * parameter while keeping those that are already set.
     *
     * @param \Symfony\Component\Routing\Route $route
     *   The route to which the parameter is to be added.
     * @param string $name
     *   The name of the parameter.
     * @param mixed $parameter
     *   The parameter's options.
     */
    protected static function addRouteParameter(Route $route, $name, $parameter) {
        $parameters = $route->getOption('parameters') ?: [];
        $parameters[$name] = $parameter;
        $route->setOption('parameters', $parameters);
    }
    
    /**
     * Get a unique route name for the JSON:API resource type and route type.
     *
     * @param \Drupal\jsonapi\ResourceType\ResourceType $resource_type
     *   The resource type for which the route collection should be created.
     * @param string $route_type
     *   The route type. E.g. 'individual' or 'collection'.
     *
     * @return string
     *   The generated route name.
     */
    public static function getRouteName(ResourceType $resource_type, $route_type) {
        return sprintf('jsonapi.%s.%s', $resource_type->getTypeName(), $route_type);
    }
    
    /**
     * Get a unique route name for the file upload resource type and route type.
     *
     * @param \Drupal\jsonapi\ResourceType\ResourceType $resource_type
     *   The resource type for which the route collection should be created.
     * @param string $route_type
     *   The route type. E.g. 'individual' or 'collection'.
     *
     * @return string
     *   The generated route name.
     */
    protected static function getFileUploadRouteName(ResourceType $resource_type, $route_type) {
        return sprintf('jsonapi.%s.%s.%s', $resource_type->getTypeName(), 'file_upload', $route_type);
    }
    
    /**
     * Determines if an array of resource types has any non-internal ones.
     *
     * @param \Drupal\jsonapi\ResourceType\ResourceType[] $resource_types
     *   The resource types to check.
     *
     * @return bool
     *   TRUE if there is at least one non-internal resource type in the given
     *   array; FALSE otherwise.
     */
    protected static function hasNonInternalTargetResourceTypes(array $resource_types) {
        return array_reduce($resource_types, function ($carry, ResourceType $target) {
            return $carry || !$target->isInternal();
        }, FALSE);
    }
    
    /**
     * Determines if an array of resource types lists non-internal "file" ones.
     *
     * @param \Drupal\jsonapi\ResourceType\ResourceType[] $resource_types
     *   The resource types to check.
     *
     * @return bool
     *   TRUE if there is at least one non-internal "file" resource type in the
     *   given array; FALSE otherwise.
     */
    protected static function hasNonInternalFileTargetResourceTypes(array $resource_types) {
        return array_reduce($resource_types, function ($carry, ResourceType $target) {
            return $carry || !$target->isInternal() && $target->getEntityTypeId() === 'file';
        }, FALSE);
    }
    
    /**
     * Gets the resource type from a route or request's parameters.
     *
     * @param array $parameters
     *   An array of parameters. These may be obtained from a route's
     *   parameter defaults or from a request object.
     *
     * @return \Drupal\jsonapi\ResourceType\ResourceType|null
     *   The resource type, NULL if one cannot be found from the given parameters.
     */
    public static function getResourceTypeNameFromParameters(array $parameters) {
        if (isset($parameters[static::JSON_API_ROUTE_FLAG_KEY]) && $parameters[static::JSON_API_ROUTE_FLAG_KEY]) {
            return $parameters[static::RESOURCE_TYPE_KEY] ?? NULL;
        }
        return NULL;
    }
    
    /**
     * Invalidates any JSON:API resource type dependent responses and routes.
     */
    public static function rebuild() {
        \Drupal::service('cache_tags.invalidator')->invalidateTags([
            'jsonapi_resource_types',
        ]);
        \Drupal::service('router.builder')->setRebuildNeeded();
    }

}