Redirect old date-formatted post permalinks

function bis_redirect_old_post_date_permalinks() {
    global $wpdb, $wp;

    // 1. Run this function only if '404' error page was expected
    if(!is_404() || empty($wp->request)) { return; }

    // 2. Check if requested URL matches the pattern (YYYY/MM/DD/post_slug)
    preg_match('/^(20[\d]{2})\/([\d]{2})\/([\d]{2})\/([^\/]+)/', $wp->request, $parts);

    // 3. Execute rest of the code if the pattern was matched
    if(!empty($parts[4])) {
        $post_year = (int) $parts[1];
        $post_month = (int) $parts[2];
        $post_day = (int) $parts[3];
        $post_slug = basename($parts[4]);

        $post = $wpdb->get_row($wpdb->prepare("
            SELECT * FROM {$wpdb->posts}
            WHERE post_name = %s
            AND post_type = 'post'
            AND YEAR(post_date) = %d
            AND MONTH(post_date) = %d
            AND DAY(post_date) = %d",
            $post_slug,
            $post_year,
            $post_month,
            $post_day
        ));

        // Trigger the redirect if the post was found
        if(!empty($post->ID)) {
            $post_url = get_permalink($attachment->ID);
            wp_safe_redirect($post_url, 301);
            exit();
        }
    }
}
add_action('template_redirect', 'bis_redirect_old_post_date_permalinks');