WPMU Appointments+ tabify service calendar add on

code.php

<?php
/*
Plugin Name: Tabify Services
Description: Create a tab or services
Plugin URI: http://premium.wpmudev.org/project/appointments-plus/
Version: 1.0
AddonType: ShortCode
Author: WPMU DEV
*/

class App_Tabify_Service {

	private function __construct () {}

	public static function serve () {
		$me = new App_Tabify_Service;
		$me->_add_hooks();
	}

	private function _add_hooks () {
		add_action( 'wp_enqueue_scripts', array( $this, 'app_ui_scripts' ) );
		add_action( 'wp_footer', array( $this, 'app_tabify_script' ) );
		add_shortcode( 'app_tabify_service', array( $this, 'app_tabify_service_cb' ) );
	}

	public function app_tabify_service_cb () {
		
		global $appointments;
		
		$services = $appointments->get_services();

		$lists = $items = '';
		$i = 0;
		
		foreach( $services as $service ){
			$lists .= '<li><a href="#tabs-' . ++$i . '">' . $service->name . '</a></li>';
			$items .= '<div id="tabs-' . $i . '">' . do_shortcode( '[app_monthly_schedule service="' . $service->ID . '"]' ) . '</div>';
		}
		
		$html = '<div id="app_tabs"><ul>';
			$html .= $lists;
		$html .= '</ul>' . $items . '</div>';
		    
		$element = '<table><tbody><tr><td colspan="2">[app_my_appointments allow_cancel="1"]</td></tr><tr><td colspan="2">' . $html . '</td></tr><tr><td colspan="2">[app_pagination month="1"]</td></tr><tr><td colspan="2">[app_login]</td></tr><tr><td colspan="2">[app_confirmation title="text" button_text="Hello"]</td></tr><tr><td colspan="2">[app_paypal]</td></tr></tbody></table>';
		
		return do_shortcode( $element );
	}
	
	public function app_tabify_script() {
		?>
		<script type="text/javascript">
		jQuery(function($) {
			$( "#app_tabs" ).tabs();
		});
		</script>
		<?php
	}
	
	public function app_ui_scripts() {
		wp_enqueue_script( 'jquery-ui-tabs' );
		wp_enqueue_style( 'app-tabs-ui', '//code.jquery.com/ui/1.11.2/themes/smoothness/jquery-ui.css' );
	}
}
App_Tabify_Service::serve();