<?php
/**
 * WP_REST_Navigation_Fallback_Controller class
 *
 * REST Controller to create/fetch a fallback Navigation Menu.
 *
 * @package WordPress
 * @subpackage REST_API
 * @since 6.3.0
 */

/**
 * REST Controller to fetch a fallback Navigation Block Menu. If needed it creates one.
 *
 * @since 6.3.0
 */
class WP_REST_Navigation_Fallback_Controller extends WP_REST_Controller {

    /**
     * The Post Type for the Controller
     *
     * @since 6.3.0
     *
     * @var string
     */
    private $post_type;

    /**
     * Constructs the controller.
     *
     * @since 6.3.0
     */
    public function __construct() {
        $this->namespace = 'wp-block-editor/v1';
        $this->rest_base = 'navigation-fallback';
        $this->post_type = 'wp_navigation';
    }

    /**
     * Registers the controllers routes.
     *
     * @since 6.3.0
     */
    public function register_routes() {

        // Lists a single nav item based on the given id or slug.
        register_rest_route(
            $this->namespace,
            '/' . $this->rest_base,
            array(
                array(
                    'methods'             => WP_REST_Server::READABLE,
                    'callback'            => array( $this, 'get_item' ),
                    'permission_callback' => array( $this, 'get_item_permissions_check' ),
                    'args'                => $this->get_endpoint_args_for_item_schema( WP_REST_Server::READABLE ),
                ),
                'schema' => array( $this, 'get_item_schema' ),
            )
        );
    }

    /**
     * Checks if a given request has access to read fallbacks.
     *
     * @since 6.3.0
     *
     * @param WP_REST_Request $request Full details about the request.
     * @return true|WP_Error True if the request has read access, WP_Error object otherwise.
     */
    public function get_item_permissions_check( $request ) {

        $post_type = get_post_type_object( $this->post_type );

        // Getting fallbacks requires creating and reading `wp_navigation` posts.
        if ( ! current_user_can( $post_type->cap->create_posts ) || ! current_user_can( 'edit_theme_options' ) || ! current_user_can( 'edit_posts' ) ) {
            return new WP_Error(
                'rest_cannot_create',
                __( 'Sorry, you are not allowed to create Navigation Menus as this user.' ),
                array( 'status' => rest_authorization_required_code() )
            );
        }

        if ( 'edit' === $request['context'] && ! current_user_can( $post_type->cap->edit_posts ) ) {
            return new WP_Error(
                'rest_forbidden_context',
                __( 'Sorry, you are not allowed to edit Navigation Menus as this user.' ),
                array( 'status' => rest_authorization_required_code() )
            );
        }

        return true;
    }

    /**
     * Gets the most appropriate fallback Navigation Menu.
     *
     * @since 6.3.0
     *
     * @param WP_REST_Request $request Full details about the request.
     * @return WP_REST_Response|WP_Error Response object on success, or WP_Error object on failure.
     */
    public function get_item( $request ) {
        $post = WP_Navigation_Fallback::get_fallback();

        if ( empty( $post ) ) {
            return rest_ensure_response( new WP_Error( 'no_fallback_menu', __( 'No fallback menu found.' ), array( 'status' => 404 ) ) );
        }

        $response = $this->prepare_item_for_response( $post, $request );

        return $response;
    }

    /**
     * Retrieves the fallbacks' schema, conforming to JSON Schema.
     *
     * @since 6.3.0
     *
     * @return array Item schema data.
     */
    public function get_item_schema() {
        if ( $this->schema ) {
            return $this->add_additional_fields_schema( $this->schema );
        }

        $this->schema = array(
            '$schema'    => 'http://json-schema.org/draft-04/schema#',
            'title'      => 'navigation-fallback',
            'type'       => 'object',
            'properties' => array(
                'id' => array(
                    'description' => __( 'The unique identifier for the Navigation Menu.' ),
                    'type'        => 'integer',
                    'context'     => array( 'view', 'edit', 'embed' ),
                    'readonly'    => true,
                ),
            ),
        );

        return $this->add_additional_fields_schema( $this->schema );
    }

    /**
     * Matches the post data to the schema we want.
     *
     * @since 6.3.0
     *
     * @param WP_Post         $item    The wp_navigation Post object whose response is being prepared.
     * @param WP_REST_Request $request Request object.
     * @return WP_REST_Response $response The response data.
     */
    public function prepare_item_for_response( $item, $request ) {
        $data = array();

        $fields = $this->get_fields_for_response( $request );

        if ( rest_is_field_included( 'id', $fields ) ) {
            $data['id'] = (int) $item->ID;
        }

        $context = ! empty( $request['context'] ) ? $request['context'] : 'view';
        $data    = $this->add_additional_fields_to_object( $data, $request );
        $data    = $this->filter_response_by_context( $data, $context );

        $response = rest_ensure_response( $data );

        if ( rest_is_field_included( '_links', $fields ) || rest_is_field_included( '_embedded', $fields ) ) {
            $links = $this->prepare_links( $item );
            $response->add_links( $links );
        }

        return $response;
    }

    /**
     * Prepares the links for the request.
     *
     * @since 6.3.0
     *
     * @param WP_Post $post the Navigation Menu post object.
     * @return array Links for the given request.
     */
    private function prepare_links( $post ) {
        return array(
            'self' => array(
                'href'       => rest_url( rest_get_route_for_post( $post->ID ) ),
                'embeddable' => true,
            ),
        );
    }
}