// SLUG FUNCTION with Polylang

add_filter( 'term_link', 'remove_product_category_base_slug', 10, 3 );
function remove_product_category_base_slug( $url, $term, $taxonomy ) {
    if ( $taxonomy !== 'product_cat' ) return $url;

    $lang = function_exists('pll_get_term_language') ? pll_get_term_language( $term->term_id ) : '';
    $lang_prefix = $lang && $lang !== pll_default_language() ? '/' . $lang : '';

    return home_url( $lang_prefix . '/' . get_term_full_slug( $term ) . '/' );
}

add_action( 'init', 'custom_product_cat_rewrite_rules', 10 );
function custom_product_cat_rewrite_rules() {
    $languages = function_exists('pll_languages_list') ? pll_languages_list() : [ get_locale() ];

    foreach ( $languages as $lang ) {
        $terms = get_terms( array(
            'taxonomy' => 'product_cat',
            'hide_empty' => false,
            'lang' => $lang,
        ) );

        if ( is_wp_error( $terms ) ) continue;

        foreach ( $terms as $term ) {
            $slug = get_term_full_slug( $term );
            $lang_prefix = $lang !== pll_default_language() ? $lang . '/' : '';

            add_rewrite_rule(
                '^' . $lang_prefix . $slug . '/?$',
                'index.php?product_cat=' . $term->slug . '&lang=' . $lang,
                'top'
            );
        }
    }
}

add_filter( 'post_type_link', 'custom_full_product_permalink', 10, 2 );
function custom_full_product_permalink( $permalink, $post ) {
    if ( $post->post_type !== 'product' ) return $permalink;

    $terms = get_the_terms( $post->ID, 'product_cat' );
    if ( ! empty( $terms ) && ! is_wp_error( $terms ) ) {
        $term = get_lowest_level_term( $terms );
        $slug = get_term_full_slug( $term );
        $lang = function_exists('pll_get_post_language') ? pll_get_post_language( $post->ID ) : '';
        $lang_prefix = $lang && $lang !== pll_default_language() ? '/' . $lang : '';

        return home_url( $lang_prefix . '/' . $slug . '/' . $post->post_name . '/' );
    }

    return home_url( '/' . $post->post_name . '/' );
}

add_action( 'init', 'custom_full_product_rewrite_rules' );
function custom_full_product_rewrite_rules() {
    $languages = function_exists('pll_languages_list') ? pll_languages_list() : [ get_locale() ];

    foreach ( $languages as $lang ) {
        $products = get_posts([
            'post_type' => 'product',
            'posts_per_page' => -1,
            'post_status' => 'publish',
            'lang' => $lang,
        ]);

        foreach ( $products as $product ) {
            $terms = get_the_terms( $product->ID, 'product_cat' );
            if ( ! empty( $terms ) && ! is_wp_error( $terms ) ) {
                $term = get_lowest_level_term( $terms );
                $slug = get_term_full_slug( $term );
                $lang_prefix = $lang !== pll_default_language() ? $lang . '/' : '';

                $rule = '^' . $lang_prefix . $slug . '/' . $product->post_name . '/?$';
                $query = 'index.php?post_type=product&name=' . $product->post_name . '&lang=' . $lang;
                add_rewrite_rule( $rule, $query, 'top' );
            }
        }
    }
}

function get_lowest_level_term( $terms ) {
    usort( $terms, function( $a, $b ) {
        return count( get_ancestors( $b->term_id, 'product_cat' ) ) <=> count( get_ancestors( $a->term_id, 'product_cat' ) );
    } );
    return $terms[0];
}

function get_term_full_slug( $term ) {
    $slugs = [];
    $ancestors = get_ancestors( $term->term_id, 'product_cat' );
    $ancestors = array_reverse( $ancestors );

    foreach ( $ancestors as $ancestor_id ) {
        $ancestor = get_term( $ancestor_id, 'product_cat' );
        $slugs[] = $ancestor->slug;
    }

    $slugs[] = $term->slug;
    return implode( '/', $slugs );
}

add_action('init', function() {
	flush_rewrite_rules();
});