<?php
/**
 * Block Renderer REST API: WP_REST_Block_Renderer_Controller class
 *
 * @package WordPress
 * @subpackage REST_API
 * @since 5.0.0
 */

/**
 * Controller which provides REST endpoint for rendering a block.
 *
 * @since 5.0.0
 *
 * @see WP_REST_Controller
 */
class WP_REST_Block_Renderer_Controller extends WP_REST_Controller {

    /**
     * Constructs the controller.
     *
     * @since 5.0.0
     */
    public function __construct() {
        $this->namespace = 'wp/v2';
        $this->rest_base = 'block-renderer';
    }

    /**
     * Registers the necessary REST API routes, one for each dynamic block.
     *
     * @since 5.0.0
     *
     * @see register_rest_route()
     */
    public function register_routes() {
        register_rest_route(
            $this->namespace,
            '/' . $this->rest_base . '/(?P<name>[a-z0-9-]+/[a-z0-9-]+)',
            array(
                'args'   => array(
                    'name' => array(
                        'description' => __( 'Unique registered name for the block.' ),
                        'type'        => 'string',
                    ),
                ),
                array(
                    'methods'             => array( WP_REST_Server::READABLE, WP_REST_Server::CREATABLE ),
                    'callback'            => array( $this, 'get_item' ),
                    'permission_callback' => array( $this, 'get_item_permissions_check' ),
                    'args'                => array(
                        'context'    => $this->get_context_param( array( 'default' => 'view' ) ),
                        'attributes' => array(
                            'description'       => __( 'Attributes for the block.' ),
                            'type'              => 'object',
                            'default'           => array(),
                            'validate_callback' => static function ( $value, $request ) {
                                $block = WP_Block_Type_Registry::get_instance()->get_registered( $request['name'] );

                                if ( ! $block ) {
                                    // This will get rejected in ::get_item().
                                    return true;
                                }

                                $schema = array(
                                    'type'                 => 'object',
                                    'properties'           => $block->get_attributes(),
                                    'additionalProperties' => false,
                                );

                                return rest_validate_value_from_schema( $value, $schema );
                            },
                            'sanitize_callback' => static function ( $value, $request ) {
                                $block = WP_Block_Type_Registry::get_instance()->get_registered( $request['name'] );

                                if ( ! $block ) {
                                    // This will get rejected in ::get_item().
                                    return true;
                                }

                                $schema = array(
                                    'type'                 => 'object',
                                    'properties'           => $block->get_attributes(),
                                    'additionalProperties' => false,
                                );

                                return rest_sanitize_value_from_schema( $value, $schema );
                            },
                        ),
                        'post_id'    => array(
                            'description' => __( 'ID of the post context.' ),
                            'type'        => 'integer',
                        ),
                    ),
                ),
                'schema' => array( $this, 'get_public_item_schema' ),
            )
        );
    }

    /**
     * Checks if a given request has access to read blocks.
     *
     * @since 5.0.0
     *
     * @global WP_Post $post Global post object.
     *
     * @param WP_REST_Request $request Request.
     * @return true|WP_Error True if the request has read access, WP_Error object otherwise.
     */
    public function get_item_permissions_check( $request ) {
        global $post;

        $post_id = isset( $request['post_id'] ) ? (int) $request['post_id'] : 0;

        if ( $post_id > 0 ) {
            $post = get_post( $post_id );

            if ( ! $post || ! current_user_can( 'edit_post', $post->ID ) ) {
                return new WP_Error(
                    'block_cannot_read',
                    __( 'Sorry, you are not allowed to read blocks of this post.' ),
                    array(
                        'status' => rest_authorization_required_code(),
                    )
                );
            }
        } else {
            if ( ! current_user_can( 'edit_posts' ) ) {
                return new WP_Error(
                    'block_cannot_read',
                    __( 'Sorry, you are not allowed to read blocks as this user.' ),
                    array(
                        'status' => rest_authorization_required_code(),
                    )
                );
            }
        }

        return true;
    }

    /**
     * Returns block output from block's registered render_callback.
     *
     * @since 5.0.0
     *
     * @global WP_Post $post Global post object.
     *
     * @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 ) {
        global $post;

        $post_id = isset( $request['post_id'] ) ? (int) $request['post_id'] : 0;

        if ( $post_id > 0 ) {
            $post = get_post( $post_id );

            // Set up postdata since this will be needed if post_id was set.
            setup_postdata( $post );
        }

        $registry   = WP_Block_Type_Registry::get_instance();
        $registered = $registry->get_registered( $request['name'] );

        if ( null === $registered || ! $registered->is_dynamic() ) {
            return new WP_Error(
                'block_invalid',
                __( 'Invalid block.' ),
                array(
                    'status' => 404,
                )
            );
        }

        $attributes = $request->get_param( 'attributes' );

        // Create an array representation simulating the output of parse_blocks.
        $block = array(
            'blockName'    => $request['name'],
            'attrs'        => $attributes,
            'innerBlocks'  => array(),
            'innerHTML'    => '',
            'innerContent' => array(),
        );

        // Render using render_block to ensure all relevant filters are used.
        $data = array(
            'rendered' => render_block( $block ),
        );

        return rest_ensure_response( $data );
    }

    /**
     * Retrieves block's output schema, conforming to JSON Schema.
     *
     * @since 5.0.0
     *
     * @return array Item schema data.
     */
    public function get_item_schema() {
        if ( $this->schema ) {
            return $this->schema;
        }

        $this->schema = array(
            '$schema'    => 'http://json-schema.org/schema#',
            'title'      => 'rendered-block',
            'type'       => 'object',
            'properties' => array(
                'rendered' => array(
                    'description' => __( 'The rendered block.' ),
                    'type'        => 'string',
                    'required'    => true,
                    'context'     => array( 'edit' ),
                ),
            ),
        );

        return $this->schema;
    }
}