Mini Shell

<?php

if ( ! defined( 'ABSPATH' ) ) {
	exit; // Exit if accessed directly.
}

if ( ! class_exists( 'ACF_Form_Gutenberg' ) ) :

	class ACF_Form_Gutenberg {

		/**
		 *  __construct
		 *
		 *  Setup for class functionality.
		 *
		 *  @date    13/12/18
		 *  @since   5.8.0
		 *
		 *  @param   void
		 *  @return  void
		 */

		function __construct() {

			// Add actions.
			add_action( 'enqueue_block_editor_assets', array( $this, 'enqueue_block_editor_assets' ) );

			// Ignore validation during meta-box-loader AJAX request.
			add_action( 'acf/validate_save_post', array( $this, 'acf_validate_save_post' ), 999 );
		}

		/**
		 *  enqueue_block_editor_assets
		 *
		 *  Allows a safe way to customize Guten-only functionality.
		 *
		 *  @date    14/12/18
		 *  @since   5.8.0
		 *
		 *  @param   void
		 *  @return  void
		 */
		function enqueue_block_editor_assets() {

			// Remove edit_form_after_title.
			add_action( 'add_meta_boxes', array( $this, 'add_meta_boxes' ), 20, 0 );

			// Call edit_form_after_title manually.
			add_action( 'block_editor_meta_box_hidden_fields', array( $this, 'block_editor_meta_box_hidden_fields' ) );

			// Customize editor metaboxes.
			add_filter( 'filter_block_editor_meta_boxes', array( $this, 'filter_block_editor_meta_boxes' ) );

			// Trigger ACF enqueue scripts as the site editor doesn't trigger this from form-post.php
			acf_enqueue_scripts(
				array(
					'uploader' => true,
				)
			);
		}

		/**
		 *  add_meta_boxes
		 *
		 *  Modify screen for Gutenberg.
		 *
		 *  @date    13/12/18
		 *  @since   5.8.0
		 *
		 *  @param   void
		 *  @return  void
		 */
		function add_meta_boxes() {

			// Remove 'edit_form_after_title' action.
			remove_action( 'edit_form_after_title', array( acf_get_instance( 'ACF_Form_Post' ), 'edit_form_after_title' ) );
		}

		/**
		 *  block_editor_meta_box_hidden_fields
		 *
		 *  Modify screen for Gutenberg.
		 *
		 *  @date    13/12/18
		 *  @since   5.8.0
		 *
		 *  @param   void
		 *  @return  void
		 */
		function block_editor_meta_box_hidden_fields() {

			// Manually call 'edit_form_after_title' function.
			acf_get_instance( 'ACF_Form_Post' )->edit_form_after_title();
		}

		/**
		 * filter_block_editor_meta_boxes
		 *
		 * description
		 *
		 * @date    5/4/19
		 * @since   5.7.14
		 *
		 * @param   type $var Description. Default.
		 * @return  type Description.
		 */
		function filter_block_editor_meta_boxes( $wp_meta_boxes ) {

			// Globals
			global $current_screen;

			// Move 'acf_after_title' metaboxes into 'normal' location.
			if ( isset( $wp_meta_boxes[ $current_screen->id ]['acf_after_title'] ) ) {

				// Extract locations.
				$locations = $wp_meta_boxes[ $current_screen->id ];

				// Ensure normal location exists.
				if ( ! isset( $locations['normal'] ) ) {
					$locations['normal'] = array();
				}
				if ( ! isset( $locations['normal']['high'] ) ) {
					$locations['normal']['high'] = array();
				}

				// Append metaboxes.
				foreach ( $locations['acf_after_title'] as $priority => $meta_boxes ) {
					$locations['normal']['high'] = array_merge( $meta_boxes, $locations['normal']['high'] );
				}

				// Update original data.
				$wp_meta_boxes[ $current_screen->id ] = $locations;
				unset( $wp_meta_boxes[ $current_screen->id ]['acf_after_title'] );

				// Avoid conflicts with saved metabox order.
				add_filter( 'get_user_option_meta-box-order_' . $current_screen->id, array( $this, 'modify_user_option_meta_box_order' ) );
			}

			// Return
			return $wp_meta_boxes;
		}

		/**
		 * modify_user_option_meta_box_order
		 *
		 * Filters the `meta-box-order_{$post_type}` value by prepending "acf_after_title" data to "normal".
		 * Fixes a bug where metaboxes with position "acf_after_title" do not appear in the block editor.
		 *
		 * @date    11/7/19
		 * @since   5.8.2
		 *
		 * @param   array $stored_meta_box_order User's existing meta box order.
		 * @return  array Modified array with meta boxes moved around.
		 */
		function modify_user_option_meta_box_order( $locations ) {
			if ( ! empty( $locations['acf_after_title'] ) ) {
				if ( ! empty( $locations['normal'] ) ) {
					$locations['normal'] = $locations['acf_after_title'] . ',' . $locations['normal'];
				} else {
					$locations['normal'] = $locations['acf_after_title'];
				}
				unset( $locations['acf_after_title'] );
			}
			return $locations;
		}

		/**
		 *  acf_validate_save_post
		 *
		 *  Ignore errors during the Gutenberg "save metaboxes" AJAX request.
		 *  Allows data to save and prevent UX issues.
		 *
		 *  @date    16/12/18
		 *  @since   5.8.0
		 *
		 *  @param   void
		 *  @return  void
		 */
		function acf_validate_save_post() {

			// Check if current request came from Gutenberg.
			if ( isset( $_GET['meta-box-loader'] ) ) {
				acf_reset_validation_errors();
			}
		}
	}

	acf_new_instance( 'ACF_Form_Gutenberg' );

endif;