<?php

/**

 * Custom classname block support flag.

 *

 * @package WordPress

 * @since 5.6.0

 */

/**

 * Registers the custom classname block attribute for block types that support it.

 *

 * @since 5.6.0

 * @access private

 *

 * @param WP_Block_Type $block_type Block Type.

 */

function wp_register_custom_classname_support( $block_type ) {

	$has_custom_classname_support = block_has_support( $block_type, array( 'customClassName' ), true );

	if ( $has_custom_classname_support ) {

		if ( ! $block_type->attributes ) {

			$block_type->attributes = array();

		}

		if ( ! array_key_exists( 'className', $block_type->attributes ) ) {

			$block_type->attributes['className'] = array(

				'type' => 'string',

			);

		}

	}

}

/**

 * Add the custom classnames to the output.

 *

 * @since 5.6.0

 * @access private

 *

 * @param  WP_Block_Type $block_type       Block Type.

 * @param  array         $block_attributes Block attributes.

 *

 * @return array Block CSS classes and inline styles.

 */

function wp_apply_custom_classname_support( $block_type, $block_attributes ) {

	$has_custom_classname_support = block_has_support( $block_type, array( 'customClassName' ), true );

	$attributes                   = array();

	if ( $has_custom_classname_support ) {

		$has_custom_classnames = array_key_exists( 'className', $block_attributes );

		if ( $has_custom_classnames ) {

			$attributes['class'] = $block_attributes['className'];

		}

	}

	return $attributes;

}

// Register the block support.

WP_Block_Supports::get_instance()->register(

	'custom-classname',

	array(

		'register_attribute' => 'wp_register_custom_classname_support',

		'apply'              => 'wp_apply_custom_classname_support',

	)

);