Adds Classes to Learndash Lessons and Topics based on whether the User has Completed Them or Not

lucanos_learndash_classes.php

function lucanos_learndash_classes( $classes ) {
	global $post;
	if( in_array( $post->post_type , array( 'sfwd-lessons' , 'sfwd-topic' ) ) ){
		$classes[] = 'learndash';

		$progress = learndash_get_course_progress( null, $post->ID );
		$classes[] = 'learndash-progress-'.( $progress['this']->completed != 1 ? 'in' : '' ).'complete';
	}
	return $classes;
}
add_filter( 'post_class' , 'lucanos_learndash_classes' );
add_filter( 'body_class' , 'lucanos_learndash_classes' );