<?php

/**

 * Block support flags.

 *

 * @package WordPress

 *

 * @since 5.6.0

 */

/**

 * Class encapsulating and implementing Block Supports.

 *

 * @since 5.6.0

 *

 * @access private

 */

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 registes 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

	 *

	 * @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 array Array of HTML attributes.

	 */

	public function apply_block_supports() {

		$block_attributes = self::$block_to_render['attrs'];

		$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();

		}

		$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 ( ! property_exists( $block_type, 'supports' ) ) {

				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 array $extra_attributes Optional. Extra attributes to render on the block wrapper.

 *

 * @return string String of HTML classes.

 */

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' );

	$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 );

}