WPMU Appointments+ show service list with providers in front end

code.php

<?php

if( ! class_exists( 'APP_Service_FP' ) )
{
        class APP_Service_FP
        {
                public $app;
                
                protected function __construct()
                {
                        global $appointments;
                        if( $appointments instanceof Appointments )
                        {
                                $this->app = $appointments;
                                
                                add_shortcode( 'app_services_fp', array( $this, 'app_services_fp_cb' ) );
                        }
                }
                
                static public function get_instance()
                {
                        static $Inst = null;
                        if( null == $Inst )
                        {
                                $Inst = new self();
                        }
                        
                        return $Inst;
                }
                
                static public function is_true( $val )
                {
                        return in_array( $val, array( 1, true, 'true', 'yes' ) );
                }
                
                public function app_services_fp_cb( $atts )
                {
                        $atts = shortcode_atts( array(
                                'name'          => true,
                                'capacity'      => true,
                                'duration'      => true,
                                'price'         => true,
                                'provider'      => false,
                                'desc'          => true,
                                'desc_length'   => 30
                        ), $atts, 'app_services_fp' );
                        
                        $services = $this->app->get_services();

                        $html = '<table width="100%">';
                                $html .= '<tr>';
                                        $html .= '<th>ID</th>';
                                        if( self::is_true( $atts['name'] ) )
                                                $html .= '<th>Name</th>';
                                        if( self::is_true( $atts['capacity'] ) )
                                                $html .= '<th>Capacity</th>';
                                        if( self::is_true( $atts['duration'] ) )
                                                $html .= '<th>Duration</th>';
                                        if( self::is_true( $atts['price'] ) )
                                                $html .= '<th>Price</th>';
                                        if( self::is_true( $atts['provider'] ) )
                                                $html .= '<th>Provider</th>';
                                        if( self::is_true( $atts['desc'] ) )
                                                $html .= '<th>Description</th>';
                                $html .= '</tr>';
                                
                                foreach( $services as $service )
                                {
                                        $html .= '<tr>';
                                                $html .= '<td valign="top">' . $service->ID . '</td>';
                                                if( self::is_true( $atts['name'] ) )
                                                        $html .= '<td valign="top">' . $service->name . '</td>';
                                                if( self::is_true( $atts['capacity'] ) )
                                                        $html .= '<td valign="top">' . $service->capacity . '</td>';
                                                if( self::is_true( $atts['duration'] ) )
                                                        $html .= '<td valign="top">' . $service->duration . ' mins</td>';
                                                if( self::is_true( $atts['price'] ) )
                                                        $html .= '<td valign="top">' . $service->price . ' ' . $this->app->options['currency'] . '</td>';
                                                if( self::is_true( $atts['provider'] ) )
                                                {
                                                        $providers = $this->app->get_workers_by_service( $service->ID );
                                                        $names = array();
                                                        
                                                        foreach( $providers as $provider )
                                                        {
                                                                $ID = $provider->ID;
                                                                $user = new WP_User( $ID );
                                                                array_push( $names, trim( $user->display_name ) == '' ? $user->user_login : $user->display_name );
                                                        }
                                                        
                                                        $html .= '<td valign="top">' . implode( ', ', $names ) . '</td>';
                                                }
                                                if( self::is_true( $atts['desc'] ) )
                                                {
                                                        $page = get_page( $service->page );
                                                        $content = substr( $page->post_content, 0, $atts['desc_length'] );
                                                        $html .= '<td valign="top"><a href="' . get_permalink( $page->ID ) . '">' . $content . '...</a></td>';
                                                }
                                        $html .= '</tr>';
                                }
                                
                        $html .= '</table>';
                        
                        return $html;
                }
        }
        
        add_action( 'init', function() {
                APP_Service_FP::get_instance();
        } );
        
}