<?php
/**
 * "Sticky" toggle for every block (post content, templates and block widgets).
 *
 * The flag is stored as a block attribute and turned into a CSS class at render
 * time, so toggling it never changes saved markup or triggers block validation.
 *
 * @package Stayrail
 */

namespace Stayrail;

defined( 'ABSPATH' ) || exit;

/**
 * Class Blocks
 */
class Blocks {

	const ATTRIBUTE = 'stayrailSticky';

	/**
	 * Hook registration.
	 */
	public static function init() {
		add_filter( 'register_block_type_args', array( __CLASS__, 'register_attribute' ), 10, 2 );
		add_filter( 'render_block', array( __CLASS__, 'render' ), 10, 2 );
		add_action( 'enqueue_block_editor_assets', array( __CLASS__, 'editor_script' ) );
		add_action( 'enqueue_block_assets', array( __CLASS__, 'editor_style' ) );
	}

	/**
	 * Declare the attribute server-side so dynamic blocks and the REST API keep it.
	 *
	 * @param array  $args Block type args.
	 * @param string $name Block name.
	 *
	 * @return array
	 */
	public static function register_attribute( $args, $name ) {
		if ( ! is_array( $args ) ) {
			return $args;
		}

		if ( ! isset( $args['attributes'] ) || ! is_array( $args['attributes'] ) ) {
			$args['attributes'] = array();
		}

		$args['attributes'][ self::ATTRIBUTE ] = array(
			'type'    => 'boolean',
			'default' => false,
		);

		return $args;
	}

	/**
	 * Add the sticky class to the outermost tag of flagged blocks.
	 *
	 * @param string $content Rendered block HTML.
	 * @param array  $block   Parsed block.
	 *
	 * @return string
	 */
	public static function render( $content, $block ) {
		if ( empty( $block['attrs'][ self::ATTRIBUTE ] ) || '' === trim( (string) $content ) ) {
			return $content;
		}

		$processor = new \WP_HTML_Tag_Processor( $content );

		if ( $processor->next_tag() ) {
			$processor->add_class( Widgets::CSS_CLASS );

			return $processor->get_updated_html();
		}

		return $content;
	}

	/**
	 * Inspector toggle in the block editor (posts, site editor and widget editor).
	 */
	public static function editor_script() {
		wp_enqueue_script(
			'stayrail-editor',
			STAYRAIL_URL . 'assets/js/editor.js',
			array( 'wp-hooks', 'wp-compose', 'wp-element', 'wp-components', 'wp-block-editor', 'wp-i18n' ),
			STAYRAIL_VERSION,
			true
		);

		wp_set_script_translations( 'stayrail-editor', 'stayrail' );
	}

	/**
	 * Outline for sticky blocks inside the (iframed) editor canvas only.
	 */
	public static function editor_style() {
		if ( ! is_admin() ) {
			return;
		}

		wp_enqueue_style( 'stayrail-editor', STAYRAIL_URL . 'assets/css/editor.css', array(), STAYRAIL_VERSION );
	}
}