<?php
/**
 * @package ACF
 * @author  WP Engine
 *
 * © 2026 Advanced Custom Fields (ACF®). All rights reserved.
 * "ACF" is a trademark of WP Engine.
 * Licensed under the GNU General Public License v2 or later.
 * https://www.gnu.org/licenses/gpl-2.0.html
 */

namespace ACF\Blocks;

// Exit if accessed directly.
defined( 'ABSPATH' ) || exit;

/**
 * The core ACF Blocks binding class.
 */
class Bindings {
	/**
	 * Block Bindings constructor.
	 */
	public function __construct() {
		// Final check we're on WP 6.5 or newer.
		if ( ! function_exists( 'register_block_bindings_source' ) ) {
			return;
		}

		add_action( 'acf/init', array( $this, 'register_binding_sources' ) );
	}

	/**
	 * Hooked to acf/init, register our binding sources.
	 */
	public function register_binding_sources() {
		if ( acf_get_setting( 'enable_block_bindings' ) ) {
			register_block_bindings_source(
				'acf/field',
				array(
					'label'              => _x( 'Custom Fields', 'The core ACF block binding source name for fields on the current page', 'acf' ),
					'get_value_callback' => array( $this, 'get_value' ),
				)
			);
		}
	}

	/**
	 * Handle returing the block binding value for an ACF meta value.
	 *
	 * @since 6.2.8
	 *
	 * @param array     $source_attrs   An array of the source attributes requested.
	 * @param \WP_Block $block_instance The block instance.
	 * @param string    $attribute_name The block's bound attribute name.
	 * @return string|null The block binding value or an empty string on failure.
	 */
	public function get_value( array $source_attrs, \WP_Block $block_instance, string $attribute_name ) {
		if ( ! isset( $source_attrs['key'] ) || ! is_string( $source_attrs['key'] ) ) {
			$value = '';
		} else {
			$post_id = acf_get_valid_post_id( false );

			// Don't output fields of a password-protected post until the password has been entered.
			if ( acf_post_password_required( $post_id ) ) {
				return '';
			}

			$field = get_field_object( $source_attrs['key'], $post_id, true, true, true );

			if ( ! $field ) {
				return '';
			}

			if ( ! acf_field_type_supports( $field['type'], 'bindings', true ) ) {
				if ( is_preview() ) {
					return apply_filters( 'acf/bindings/field_not_supported_message', '[' . esc_html__( 'The requested ACF field type does not support output in Block Bindings or the ACF shortcode.', 'acf' ) . ']' );
				} else {
					return '';
				}
			}

			if ( isset( $field['allow_in_bindings'] ) && ! $field['allow_in_bindings'] ) {
				if ( is_preview() ) {
					return apply_filters( 'acf/bindings/field_not_allowed_message', '[' . esc_html__( 'The requested ACF field is not allowed to be output in bindings or the ACF Shortcode.', 'acf' ) . ']' );
				} else {
					return '';
				}
			}

			$value = $field['value'];

			// Reduce User data to IDs. The escaped value is rebuilt from the reduced value, as escaping turns user objects into false.
			if ( acf_bindings_should_reduce_user_data( $field, $post_id, 'bindings' ) ) {
				$value = acf_bindings_reduce_user_value( acf_format_value( acf_get_value( $post_id, $field ), $post_id, $field ), $field );
				$value = map_deep( $value, 'acf_esc_html' );
			}

			// Anything we can't output as a string would throw an error, so it's returned as null for safety.
			$value = acf_bindings_flatten_value( $value );
		}

		return apply_filters( 'acf/blocks/binding_value', $value, $source_attrs, $block_instance, $attribute_name );
	}
}