function quiz_mc_post_type_rewrite_rules() {
    add_rewrite_tag('%course%','([^&]+)');
    add_rewrite_tag('%quiz%', '([^&]+)');
    add_rewrite_tag('%quiz_mc_post_type%', '([^/]+)');
    add_permastruct('quiz_mc_post_type', '/course/%course%/quiz/%quiz%/question/%quiz_mc_post_type%', true);
    add_rewrite_rule('course/([^/]*)/quiz/([^/]*)/question/([^/]*)/?','index.php?post_type=quiz_wc_post_type&course=$matches[1]&quiz=$matches[2]&mc_quiz_question=$matches[3]','top');
}
add_action( 'init', 'quiz_mc_post_type_rewrite_rules' );


function quiz_mc_post_type() {
    $labels = array(
        'name'                  => _x( 'Multiple Choice Questions', 'Post Type General Name', 'text_domain' ),
        'singular_name'         => _x( 'Multiple Choice Question', 'Post Type Singular Name', 'text_domain' ),
        'menu_name'             => __( 'Multiple Choice Questions', 'text_domain' ),
        'name_admin_bar'        => __( 'Multiple Choice Question', 'text_domain' ),
        'archives'              => __( 'Multiple Choice Question Archives', 'text_domain' ),
        'attributes'            => __( 'Multiple Choice Question Attributes', 'text_domain' ),
        'parent_item_colon'     => __( 'Parent Multiple Choice Question:', 'text_domain' ),
        'all_items'             => __( 'All Multiple Choice Questions', 'text_domain' ),
        'add_new_item'          => __( 'Add New Multiple Choice Question', 'text_domain' ),
        'add_new'               => __( 'Add New', 'text_domain' ),
        'new_item'              => __( 'New Multiple Choice Question', 'text_domain' ),
        'edit_item'             => __( 'Edit Multiple Choice Question', 'text_domain' ),
        'update_item'           => __( 'Update Multiple Choice Question', 'text_domain' ),
        'view_item'             => __( 'View Multiple Choice Question', 'text_domain' ),
        'view_items'            => __( 'View Multiple Choice Questions', 'text_domain' ),
        'search_items'          => __( 'Search Multiple Choice Question', 'text_domain' ),
        'not_found'             => __( 'Not found', 'text_domain' ),
        'not_found_in_trash'    => __( 'Not found in Trash', 'text_domain' ),
        'featured_image'        => __( 'Featured Image', 'text_domain' ),
        'set_featured_image'    => __( 'Set featured image', 'text_domain' ),
        'remove_featured_image' => __( 'Remove featured image', 'text_domain' ),
        'use_featured_image'    => __( 'Use as featured image', 'text_domain' ),
        'insert_into_item'      => __( 'Insert into Multiple Choice Question', 'text_domain' ),
        'uploaded_to_this_item' => __( 'Uploaded to this Multiple Choice Question', 'text_domain' ),
        'items_list'            => __( 'Multiple Choice Questions list', 'text_domain' ),
        'items_list_navigation' => __( 'Multiple Choice Questions list navigation', 'text_domain' ),
        'filter_items_list'     => __( 'Filter Multiple Choice Questions list', 'text_domain' ),
    );
    $rewrite = array(
        'slug'                  => 'course/%course%/quiz/%quiz%/question',
        'with_front'            => false,
        'pages'                 => true,
        'feeds'                 => false,
    );
    $args = array(
        'label'                 => __( 'Multiple Choice Question', 'text_domain' ),
        'description'           => __( 'Post type used to house quizs', 'text_domain' ),
        'labels'                => $labels,
        'supports'              => array( 'title', 'editor', 'author', 'revisions', 'post-formats' ),
        'hierarchical'          => false,
        'public'                => true,
        'show_ui'               => true,
        'show_in_menu'          => true,
        'menu_position'         => 5,
        'show_in_admin_bar'     => true,
        'show_in_nav_menus'     => false,
        'can_export'            => true,
        'has_archive'           => false,
        'exclude_from_search'   => true,
        'publicly_queryable'    => true,
        'query_var'                         => 'mc_quiz_question',
        'rewrite'               => $rewrite,
        'capability_type'       => 'post',
    );
    register_post_type( 'quiz_mc_post_type', $args );
}
add_action( 'init', 'quiz_mc_post_type', 0 );

function quiz_mc_post_type_permalinks($permalink, $post, $leavename) {
    $post_id = $post->ID;
    if($post->post_type != 'quiz_mc_post_type' || empty($permalink) || in_array($post->post_status, array('draft', 'pending', 'auto-draft'))){
        return $permalink;
    }
    // GETS THE QUESTIONS PARENT WHICH IS A QUIZ
    $quiz = $post->post_parent;
    $actual_quiz = get_post( $quiz );
    $actual_quiz_name = $actual_quiz->post_name;

    // GETS THE QUIZ PARENT WHICH IS A COURSE
    $course = $actual_quiz->post_parent;
    $actual_course = get_post( $course );
    $actual_course_name = $actual_course->post_name;

    $needles = array("%course%", "%quiz%");
    $replacements = array($actual_course_name, $actual_quiz_name);

    $permalink = str_replace($needles, $replacements, $permalink);
    return $permalink;
}
add_filter('post_type_link', 'quiz_mc_post_type_permalinks', 10, 3);