Add WPML translations to WP2Static v7

wp2static_v7_wpml.php

<?php
function sg_get_translated_posts_urls() {
	$default_lang = apply_filters( 'wpml_default_language', NULL );

	$ids = get_posts( array(
		'fields'           => 'ids',
		'post_type'        => array( 'post', 'page' ),
		'numberposts'      => -1,
		'suppress_filters' => true, // Get posts in all languages
	) );

	$permalinks = array();
	foreach ( $ids as $id ) {
		$lang = apply_filters( 'wpml_post_language_details', NULL, $id );

		// We only need translations; skip posts in default language
		if ( $lang['language_code'] === $default_lang ) {
			continue;
		}

		$permalink      = get_permalink( $id );
		$wpml_permalink = apply_filters( 'wpml_permalink', $permalink, $lang['language_code'] );

		// Strip home URL (domain) from permalink
		$wpml_permalink = str_replace( trailingslashit( home_url() ), '/', $wpml_permalink );

		$permalinks[] = $wpml_permalink;
	}

	return $permalinks;
}

function sg_add_additional_urls( $url_queue ) {

	/* Add WPML translations */

	$translation_urls = sg_get_translated_posts_urls();

	$url_queue = array_merge(
		$url_queue,
		$translation_urls
	);

	return $url_queue;
}
add_filter( 'wp2static_modify_initial_crawl_list', 'sg_add_additional_urls' );

@fertek You are right, thanks for the simplification!

Edited: After all I was able to get it working using fertek's suggestion above using the true parameter after all. For this to work reliably, you need to go to WPML > Languages > and disable "Adjust IDs for multilingual functionality". Otherwise, the IDs get converted and you will be missing some pages during the crawl.

Thank you for sharing these solutions.

@bkno Glad to hear that it works for you now!