<?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, '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',
);
}
}
}

/**
* Adds 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, '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',
)
);