l $walk_dirs   Whether the 'directories' making up the structure should be walked over
	 *                             and rewrite rules built for each in-turn. Default true.
	 *     @type bool $endpoints   Whether endpoints should be applied to the generated rules. Default true.
	 * }
	 */
	public function add_permastruct( $name, $struct, $args = array() ) {
		// Back-compat for the old parameters: $with_front and $ep_mask.
		if ( ! is_array( $args ) ) {
			$args = array( 'with_front' => $args );
		}

		if ( func_num_args() === 4 ) {
			$args['ep_mask'] = func_get_arg( 3 );
		}

		$defaults = array(
			'with_front'  => true,
			'ep_mask'     => EP_NONE,
			'paged'       => true,
			'feed'        => true,
			'forcomments' => false,
			'walk_dirs'   => true,
			'endpoints'   => true,
		);

		$args = array_intersect_key( $args, $defaults );
		$args = wp_parse_args( $args, $defaults );

		if ( $args['with_front'] ) {
			$struct = $this->front . $struct;
		} else {
			$struct = $this->root . $struct;
		}

		$args['struct'] = $struct;

		$this->extra_permastructs[ $name ] = $args;
	}

	/**
	 * Removes a permalink structure.
	 *
	 * @since 4.5.0
	 *
	 * @param string $name Name for permalink structure.
	 */
	public function remove_permastruct( $name ) {
		unset( $this->extra_permastructs[ $name ] );
	}

	/**
	 * Removes rewrite rules and then recreate rewrite rules.
	 *
	 * Calls WP_Rewrite::wp_rewrite_rules() after removing the 'rewrite_rules' option.
	 * If the function named 'save_mod_rewrite_rules' exists, it will be called.
	 *
	 * @since 2.0.1
	 *
	 * @param bool $hard Whether to update .htaccess (hard flush) or just update rewrite_rules option (soft flush). Default is true (hard).
	 */
	public function flush_rules( $hard = true ) {
		static $do_hard_later = null;

		// Prevent this action from running before everyone has registered their rewrites.
		if ( ! did_action( 'wp_loaded' ) ) {
			add_action( 'wp_loaded', array( $this, 'flush_rules' ) );
			$do_hard_later = ( isset( $do_hard_later ) ) ? $do_hard_later || $hard : $hard;
			return;
		}

		if ( isset( $do_hard_later ) ) {
			$hard = $do_hard_later;
			unset( $do_hard_later );
		}

		$this->refresh_rewrite_rules();

		/**
		 * Filters whether a "hard" rewrite rule flush should be performed when requested.
		 *
		 * A "hard" flush updates .htaccess (Apache) or web.config (IIS).
		 *
		 * @since 3.7.0
		 *
		 * @param bool $hard Whether to flush rewrite rules "hard". Default true.
		 */
		if ( ! $hard || ! apply_filters( 'flush_rewrite_rules_hard', true ) ) {
			return;
		}
		if ( function_exists( 'save_mod_rewrite_rules' ) ) {
			save_mod_rewrite_rules();
		}
		if ( function_exists( 'iis7_save_url_rewrite_rules' ) ) {
			iis7_save_url_rewrite_rules();
		}
	}

	/**
	 * Sets up the object's properties.
	 *
	 * The 'use_verbose_page_rules' object property will be set to true if the
	 * permalink structure begins with one of the following: '%postname%', '%category%',
	 * '%tag%', or '%author%'.
	 *
	 * @since 1.5.0
	 */
	public function init() {
		$this->extra_rules         = array();
		$this->non_wp_rules        = array();
		$this->endpoints           = array();
		$this->permalink_structure = get_option( 'permalink_structure' );
		$this->front               = substr( $this->permalink_structure, 0, strpos( $this->permalink_structure, '%' ) );
		$this->root                = '';

		if ( $this->using_index_permalinks() ) {
			$this->root = $this->index . '/';
		}

		unset( $this->author_structure );
		unset( $this->date_structure );
		unset( $this->page_structure );
		unset( $this->search_structure );
		unset( $this->feed_structure );
		unset( $this->comment_feed_structure );

		$this->use_trailing_slashes = str_ends_with( $this->permalink_structure, '/' );

		// Enable generic rules for pages if permalink structure doesn't begin with a wildcard.
		if ( preg_match( '/^[^%]*%(?:postname|category|tag|author)%/', $this->permalink_structure ) ) {
			$this->use_verbose_page_rules = true;
		} else {
			$this->use_verbose_page_rules = false;
		}
	}

	/**
	 * Sets the main permalink structure for the site.
	 *
	 * Will update the 'permalink_structure' option, if there is a difference
	 * between the current permalink structure and the parameter value. Calls
	 * WP_Rewrite::init() after the option is updated.
	 *
	 * Fires the {@see 'permalink_structure_changed'} action once the init call has
	 * processed passing the old and new values
	 *
	 * @since 1.5.0
	 *
	 * @param string $permalink_structure Permalink structure.
	 */
	public function set_permalink_structure( $permalink_structure ) {
		if ( $this->permalink_structure !== $permalink_structure ) {
			$old_permalink_structure = $this->permalink_structure;
			update_option( 'permalink_structure', $permalink_structure );

			$this->init();

			/**
			 * Fires after the permalink structure is updated.
			 *
			 * @since 2.8.0
			 *
			 * @param string $old_permalink_structure The previous permalink structure.
			 * @param string $permalink_structure     The new permalink structure.
			 */
			do_action( 'permalink_structure_changed', $old_permalink_structure, $permalink_structure );
		}
	}

	/**
	 * Sets the category base for the category permalink.
	 *
	 * Will update the 'category_base' option, if there is a difference between
	 * the current category base and the parameter value. Calls WP_Rewrite::init()
	 * after the option is updated.
	 *
	 * @since 1.5.0
	 *
	 * @param string $category_base Category permalink structure base.
	 */
	public function set_category_base( $category_base ) {
		if ( get_option( 'category_base' ) !== $category_base ) {
			update_option( 'category_base', $category_base );
			$this->init();
		}
	}

	/**
	 * Sets the tag base for the tag permalink.
	 *
	 * Will update the 'tag_base' option, if there is a difference between the
	 * current tag base and the parameter value. Calls WP_Rewrite::init() after
	 * the option is updated.
	 *
	 * @since 2.3.0
	 *
	 * @param string $tag_base Tag permalink structure base.
	 */
	public function set_tag_base( $tag_base ) {
		if ( get_option( 'tag_base' ) !== $tag_base ) {
			update_option( 'tag_base', $tag_base );
			$this->init();
		}
	}

	/**
	 * Constructor - Calls init(), which runs setup.
	 *
	 * @since 1.5.0
	 */
	public function __construct() {
		$this->init();
	}
}