<?php
/**
 * Server-side block attribute registration.
 *
 * @package BlockSieve
 */

namespace BlockSieve\Services;

use BlockSieve\HookLoader;

/**
 * Registers the `visibility` attribute on every server-side block type.
 *
 * The editor adds the attribute in JS (`src/blocks/add-attribute.js`), but
 * server-rendered previews go through the REST `block-renderer` route, which
 * validates the posted attributes against the *server* registration. Without
 * this, every dynamic block previewed with ServerSideRender (Archives, Calendar,
 * RSS, Tag Cloud, …) fails with a 400 "Invalid parameter(s): attributes".
 */
final class BlockExtensionService {

	/**
	 * Hook loader.
	 *
	 * @var HookLoader
	 */
	private HookLoader $hooks;

	/**
	 * Constructor.
	 *
	 * @param HookLoader $hooks Hook loader.
	 */
	public function __construct( HookLoader $hooks ) {
		$this->hooks = $hooks;
	}

	/**
	 * Queues the block registration filter via the hook loader.
	 *
	 * @return void
	 */
	public function register(): void {
		$this->hooks->add_filter( 'register_block_type_args', array( $this, 'add_attribute' ) );
	}

	/**
	 * Adds the visibility attribute schema to a block type's arguments.
	 *
	 * No default is declared, so server-side an unconfigured block simply has no
	 * `visibility` attribute and RenderService skips it.
	 *
	 * Accepts `mixed` because `register_block_type_args` is a public filter:
	 * another plugin may hand it something that is not an array, and a
	 * TypeError here would take down block registration.
	 *
	 * @param mixed $args Block type arguments.
	 * @return mixed
	 */
	public function add_attribute( $args ) {
		if ( ! is_array( $args ) ) {
			return $args;
		}

		$attributes = isset( $args['attributes'] ) && is_array( $args['attributes'] ) ? $args['attributes'] : array();

		if ( ! isset( $attributes[ RenderService::ATTRIBUTE_KEY ] ) ) {
			$attributes[ RenderService::ATTRIBUTE_KEY ] = array( 'type' => 'object' );
			$args['attributes']                         = $attributes;
		}

		return $args;
	}
}