Remove custom post slug and add category to custom post type

Use This…

function chapter_post_type_init() {
        $labels = array(
                'name' => 'Chapters',
                'singular_name' => 'Chapter',
                'add_new' => 'Add New',
                'add_new_item' => 'Add New Chapter',
                'edit_item' => 'Edit Chapter',
                'new_item' => 'New Chapter',
                'all_items' => 'All Chapters',
                'view_item' => 'View Chapter',
                'search_items' => 'Search Chapters',
                'not_found' =>  'No chapters found',
                'not_found_in_trash' => 'No chapters found in Trash',
                'parent_item_colon' => '',
                'menu_name' => 'Books'
        );

        $args = array(
                'labels' => $labels,
                'public' => true,
                'publicly_queryable' => true,
                'show_ui' => true,
                'show_in_menu' => true,
                'taxonomies'   => array( 'category', 'post_tag' ),
                'query_var' => true,
                'rewrite' => array( 'slug' => '/%category%','with_front' => false,'hierarchical' => true),
                'capability_type' => 'post',
                'has_archive' => true,
                'hierarchical' => false,
                'menu_position' => 100,
                'supports' => array( 'title', 'editor', 'author', 'excerpt')
        );
        register_post_type( 'chapter', $args );
}
add_action( 'init', 'chapter_post_type_init' );


add_filter('post_type_link', 'book_permalink_structure', 10, 6);
function book_permalink_structure($post_link, $post, $leavename, $sample)
{
    if ( false !== strpos( $post_link, '%category%' ) ) {
        if( $book_type_term = wp_get_object_terms( $post->ID, 'category' ) )
        {
            if($book_type_term[1]->parent == 0 ){
             $post_link = str_replace( '%category%', array_pop( $book_type_term )->slug, $post_link );              
            }else{
        $post_link = str_replace( '%category%', $book_type_term[0]->slug."https://wordpress.stackexchange.com/".$book_type_term[1]->slug, $post_link );
            }
        }
    }
    return $post_link;
}