Add Unified Product SKU with ID for Facebook Feed || WPML || PFE

function adt_wpml_unified_product_sku_id( $product_data, $feed, $product ) {

    // Check if the feed is for Facebook dynamic remarketing

    if( isset($feed->channel['fields']) && $feed->channel['fields'] == 'facebook_drm' ) {

        $product_id = $product->get_id();

        // Get the original product ID from WPML (default language)

        $wpml_product_id = apply_filters('wpml_original_element_id', NULL, $product_id);

        if ( $wpml_product_id ) {

            $product_id = $wpml_product_id;

        }

        // Append original product ID to SKU to create a unified SKU ID

        if( ! empty( $product_data['sku'] ) ) {

            $product_data['sku_id'] = $product_data['sku'] . '_' . $product_id;

        }

    }

    return $product_data;

}

add_filter( 'adt_get_product_data', 'adt_wpml_unified_product_sku_id', 10, 3 );