illar_content = '';
		$dashicon_format   = '<span class="dashicons dashicons-%s rm-mark-page-icon"></span>';

		if ( is_singular( Helper::get_accessible_post_types() ) ) {
			if ( get_post_meta( get_the_ID(), 'rank_math_pillar_content', true ) === 'on' ) {
				$is_pillar_content = sprintf( $dashicon_format, 'yes' );
			}

			$this->add_sub_menu(
				'pillar-content',
				[
					'title' => $is_pillar_content . esc_html__( 'As Pillar Content', 'rank-math' ),
					'href'  => '#pillar_content',
					'meta'  => [ 'class' => 'mark-page-as' ],
				],
				'mark-me'
			);
		}

		if ( Paper::get() ) {
			$robots        = Paper::get()->get_robots();
			$noindex_check = in_array( 'noindex', $robots, true ) ? sprintf( $dashicon_format, 'yes' ) : '';
			$this->add_sub_menu(
				'no-index',
				[
					'title' => $noindex_check . esc_html__( 'As NoIndex', 'rank-math' ),
					'href'  => '#noindex',
					'meta'  => [ 'class' => 'mark-page-as' ],
				],
				'mark-me'
			);

			$nofollow_check = in_array( 'nofollow', $robots, true ) ? sprintf( $dashicon_format, 'yes' ) : '';
			$this->add_sub_menu(
				'no-follow',
				[
					'title' => $nofollow_check . esc_html__( 'As NoFollow', 'rank-math' ),
					'href'  => '#nofollow',
					'meta'  => [ 'class' => 'mark-page-as' ],
				],
				'mark-me'
			);
		}
	}

	/**
	 * Third party SEO Tools, like the Google Structured Data Testing Tool.
	 */
	private function add_seo_tools() {
		$this->add_sub_menu(
			'third-party',
			[
				'title'    => esc_html__( 'External Tools', 'rank-math' ),
				'href'     => '#',
				'priority' => 200,
			]
		);

		$url   = rawurlencode( Url::get_current_url() );
		$items = [
			'google-pagespeed'           => [
				'title' => esc_html__( 'Google PageSpeed', 'rank-math' ),
				'href'  => 'https://developers.google.com/speed/pagespeed/insights/?url=' . $url,
				'meta'  => [ 'title' => esc_html__( 'Google PageSpeed Insights', 'rank-math' ) ],
			],

			'google-richresults-mobile'  => [
				'title' => esc_html__( 'Google Rich Results (Mobile)', 'rank-math' ),
				'href'  => 'https://search.google.com/test/rich-results?url=' . $url . '&user_agent=1',
				'meta'  => [ 'title' => esc_html__( 'Google Rich Results Test - Googlebot Smartphone', 'rank-math' ) ],
			],

			'google-richresults-desktop' => [
				'title' => esc_html__( 'Google Rich Results (Desktop)', 'rank-math' ),
				'href'  => 'https://search.google.com/test/rich-results?url=' . $url . '&user_agent=2',
				'meta'  => [ 'title' => esc_html__( 'Google Rich Results Test - Googlebot Desktop', 'rank-math' ) ],
			],

			'google-cache'               => [
				'title' => esc_html__( 'Google Cache', 'rank-math' ),
				'href'  => 'https://webcache.googleusercontent.com/search?q=cache:' . $url,
				'meta'  => [ 'title' => esc_html__( 'See Google\'s cached version of your site', 'rank-math' ) ],
			],

			'fb-debugger'                => [
				'title' => esc_html__( 'Facebook Debugger', 'rank-math' ),
				'href'  => 'https://developers.facebook.com/tools/debug/sharing/?q=' . $url,
				'meta'  => [ 'title' => esc_html__( 'Facebook Sharing Debugger', 'rank-math' ) ],
			],
		];

		foreach ( $items as $id => $args ) {
			$args['meta']['target'] = '_blank';
			$this->add_sub_menu( $id, $args, 'third-party' );
		}
	}

	/**
	 * Add sub menu item
	 *
	 * @param string $id     Unique ID for the node.
	 * @param array  $args   Arguments for adding a node.
	 * @param string $parent Node parent.
	 */
	public function add_sub_menu( $id, $args, $parent = '' ) {
		$args['priority']   = isset( $args['priority'] ) ? $args['priority'] : 999;
		$args['id']         = 'rank-math-' . $id;
		$args['parent']     = '' !== $parent ? 'rank-math-' . $parent : self::MENU_IDENTIFIER;
		$this->items[ $id ] = $args;
	}

	/**
	 * Can current user has capability for admin menu.
	 *
	 * @return bool
	 */
	private function can_add_menu() {
		return Helper::has_cap( 'admin_bar' );
	}

	/**
	 * Can add mark me menu.
	 *
	 * @return bool
	 */
	private function can_add_mark_menu() {
		return $this->is_front() && Helper::has_cap( 'onpage_general' );
	}

	/**
	 * Is frontend.
	 *
	 * @return bool
	 */
	private function is_front() {
		return ! is_admin() && ! is_preview();
	}

	/**
	 * Sort admin bar items callback.
	 *
	 * @param array $item1 Item A to compare.
	 * @param array $item2 Item B to compare.
	 *
	 * @return integer
	 */
	private function sort_by_priority( $item1, $item2 ) {
		if ( $item1['priority'] === $item2['priority'] ) {
			return $item1['order'] < $item2['order'] ? -1 : 1;
		}

		return $item1['priority'] < $item2['priority'] ? -1 : 1;
	}

	/**
	 * Get Rank Math icon.
	 *
	 * @param integer $width Width of the icon.
	 *
	 * @return string
	 */
	private function get_icon( $width = 20 ) {
		return '<svg viewBox="0 0 462.03 462.03" xmlns="http://www.w3.org/2000/svg" width="' . $width . '"><g><path d="m462 234.84-76.17 3.43 13.43 21-127 81.18-126-52.93-146.26 60.97 10.14 24.34 136.1-56.71 128.57 54 138.69-88.61 13.43 21z"/><path d="m54.1 312.78 92.18-38.41 4.49 1.89v-54.58h-96.67zm210.9-223.57v235.05l7.26 3 89.43-57.05v-181zm-105.44 190.79 96.67 40.62v-165.19h-96.67z"/></g></svg>';
	}

}