Enhanced Media Library and WPML sync terms

wpml-enhanced-media-library.php

<?php
/*
Plugin Name: Enhanced Media Library and WPML
Description: Synchronizes terms
Version: 0.0.1
*/

add_action( 'set_object_terms', 'wpml_eml_sync_terms', 10, 6 );

function wpml_eml_sync_terms( $object_id, $terms, $tt_ids, $taxonomy, $append, $old_tt_ids ) {

	if ( $taxonomy !== 'media_category' ) {
		return;
	}

	$trid = apply_filters( 'wpml_element_trid', null, $object_id, 'post_attachment' );

	if ( ! $trid ) {
		return;
	}

	$attachments = apply_filters( 'wpml_get_element_translations', array(), $trid, 'post_attachment' );

	if ( ! $attachments ) {
		return;
	}

	foreach ( $attachments as $language_code => $attachment ) {

		if ( (int) $attachment->element_id !== $object_id ) {

			$translated_terms = array();

			foreach ( $terms as $term_id ) {
				$translated_term_id = apply_filters( 'wpml_object_id', $term_id, $taxonomy, false, $language_code );
				if ( $translated_term_id ) {
					$translated_terms[] = $translated_term_id;
				}
			}

			remove_action( 'set_object_terms', 'wpml_eml_sync_terms', 10, 6 );
			wp_set_object_terms( $attachment->element_id, $translated_terms, $taxonomy, false );
			add_action( 'set_object_terms', 'wpml_eml_sync_terms', 10, 6 );
		}
	}
}