<?php
/**
* Block support flags.
*
* @package WordPress
*
* @since 5.6.0
*/

/**
* Class encapsulating and implementing Block Supports.
*
* @since 5.6.0
*
* @access private
*/
#[AllowDynamicProperties]
class WP_Block_Supports {

/**
* Config.
*
* @since 5.6.0
* @var array
*/
private $block_supports = array();

/**
* Tracks the current block to be rendered.
*
* @since 5.6.0
* @var array
*/
public static $block_to_render = null;

/**
* Container for the main instance of the class.
*
* @since 5.6.0
* @var WP_Block_Supports|null
*/
private static $instance = null;

/**
* Utility method to retrieve the main instance of the class.
*
* The instance will be created if it does not exist yet.
*
* @since 5.6.0
*
* @return WP_Block_Supports The main instance.
*/
public static function get_instance() {
if ( null === self::$instance ) {
self::$instance = new self();
}

return self::$instance;
}

/**
* Initializes the block supports. It registers the block supports block attributes.
*
* @since 5.6.0
*/
public static function init() {
$instance = self::get_instance();
$instance->register_attributes();
}

/**
* Registers a block support.
*
* @since 5.6.0
*
* @link https://developer.wordpress.org/block-editor/reference-guides/block-api/block-supports/
*
* @param string $block_support_name Block support name.
* @param array $block_support_config Array containing the properties of the block support.
*/
public function register( $block_support_name, $block_support_config ) {
$this->block_supports[ $block_support_name ] = array_merge(
$block_support_config,
array( 'name' => $block_support_name )
);
}

/**
* Generates an array of HTML attributes, such as classes, by applying to
* the given block all of the features that the block supports.
*
* @since 5.6.0
*
* @return string[] Array of HTML attribute values keyed by their name.
*/
public function apply_block_supports() {
$block_type = WP_Block_Type_Registry::get_instance()->get_registered(
self::$block_to_render['blockName']
);

// If no render_callback, assume styles have been previously handled.
if ( ! $block_type || empty( $block_type ) ) {
return array();
}

$block_attributes = array_key_exists( 'attrs', self::$block_to_render ) && is_array( self::$block_to_render['attrs'] )
? $block_type->prepare_attributes_for_render( self::$block_to_render['attrs'] )
: array();

$output = array();
foreach ( $this->block_supports as $block_support_config ) {
if ( ! isset( $block_support_config['apply'] ) ) {
continue;
}

$new_attributes = call_user_func(
$block_support_config['apply'],
$block_type,
$block_attributes
);

if ( ! empty( $new_attributes ) ) {
foreach ( $new_attributes as $attribute_name => $attribute_value ) {
if ( empty( $output[ $attribute_name ] ) ) {
$output[ $attribute_name ] = $attribute_value;
} else {
$output[ $attribute_name ] .= " $attribute_value";
}
}
}
}

return $output;
}

/**
* Registers the block attributes required by the different block supports.
*
* @since 5.6.0
*/
private function register_attributes() {
$block_registry = WP_Block_Type_Registry::get_instance();
$registered_block_types = $block_registry->get_all_registered();
foreach ( $registered_block_types as $block_type ) {
if ( ! ( $block_type instanceof WP_Block_Type ) ) {
continue;
}
if ( ! $block_type->attributes ) {
$block_type->attributes = array();
}

foreach ( $this->block_supports as $block_support_config ) {
if ( ! isset( $block_support_config['register_attribute'] ) ) {
continue;
}

call_user_func(
$block_support_config['register_attribute'],
$block_type
);
}
}
}
}

/**
* Generates a string of attributes by applying to the current block being
* rendered all of the features that the block supports.
*
* @since 5.6.0
*
* @param string[] $extra_attributes Optional. Array of extra attributes to render on the block wrapper.
* @return string String of HTML attributes.
*/
function get_block_wrapper_attributes( $extra_attributes = array() ) {
$new_attributes = WP_Block_Supports::get_instance()->apply_block_supports();

if ( empty( $new_attributes ) && empty( $extra_attributes ) ) {
return '';
}

// This is hardcoded on purpose.
// We only support a fixed list of attributes.
$attributes_to_merge = array( 'style', 'class', 'id', 'aria-label' );
$attributes = array();
foreach ( $attributes_to_merge as $attribute_name ) {
if ( empty( $new_attributes[ $attribute_name ] ) && empty( $extra_attributes[ $attribute_name ] ) ) {
continue;
}

if ( empty( $new_attributes[ $attribute_name ] ) ) {
$attributes[ $attribute_name ] = $extra_attributes[ $attribute_name ];
continue;
}

if ( empty( $extra_attributes[ $attribute_name ] ) ) {
$attributes[ $attribute_name ] = $new_attributes[ $attribute_name ];
continue;
}

$attributes[ $attribute_name ] = $extra_attributes[ $attribute_name ] . ' ' . $new_attributes[ $attribute_name ];
}

foreach ( $extra_attributes as $attribute_name => $value ) {
if ( ! in_array( $attribute_name, $attributes_to_merge, true ) ) {
$attributes[ $attribute_name ] = $value;
}
}

if ( empty( $attributes ) ) {
return '';
}

$normalized_attributes = array();
foreach ( $attributes as $key => $value ) {
$normalized_attributes[] = $key . '="' . esc_attr( $value ) . '"';
}

return implode( ' ', $normalized_attributes );
}