Creates a shortcode and displays Pro Site ads on sidebar. Requires Pro Sites plugin

wpmudev-ps-adsinsidebar.php

<?php
/*
Plugin Name: WPMUDEV Pro Site Ads on sidebar
Plugin URI: https://premium.wpmudev.org/
Description: Creates a shortcode and displays Pro Site ads on sidebar
Author: Panos Lyrakis @ WPMUDEV
Author URI: https://premium.wpmudev.org/
License: GPLv2 or later
*/

if( ! class_exists( 'WPMUDEV_PS_Sidebar_Ads' ) ){
	class WPMUDEV_PS_Sidebar_Ads
	{	

		var $ad_counter;
		private $_shown_ads = false;
		private static $_instance = null;	

		public static function get_instance() {
	        if ( is_null( self::$_instance ) ) {
	            self::$_instance = new WPMUDEV_PS_Sidebar_Ads();
	        }
	        return self::$_instance;
	    }
		
		private function __construct(){

			add_shortcode( 'wpmudev_ps_sidebar_ads', array( $this, 'ps_sidebar_ads_sh' ) );

			add_action( 'get_sidebar', array( $this, 'show_sidebar_ads' ), 1 );

		}

		public function ps_sidebar_ads_sh( $atts, $content ){

			global $psts;

			if( ! class_exists( 'ProSites' ) || ! $this->ok_to_show_ads() || is_feed() ){
				return $content;
			}

			$per_page = $psts->get_setting( 'ads_count', 3 );
			
			if ( $this->ad_counter < $per_page ) {
				$content = $psts->get_setting( 'ads_before_code' ) . $content;
				$this->ad_counter ++;
			}
						
			if ( $this->ad_counter < $per_page ) {
				$content = $content . $psts->get_setting( 'ads_after_code' );
				$this->ad_counter ++;
			}
				
			return "<div class=\"ps_sidebar_ads\">{$content}</div>";

		}

		public function show_sidebar_ads( $name ){

			if( ! $this->_shown_ads ){
			// OR
			// if( $name == '' ){
				echo do_shortcode( '[wpmudev_ps_sidebar_ads]' );			
			}			
			$this->_shown_ads = true;

		}

		function ok_to_show_ads( $blog_id = null ) {
			global $ProSites_Module_Ads;

			if ( isset( $ProSites_Module_Ads ) && is_object( $ProSites_Module_Ads ) ) {
				return $ProSites_Module_Ads->show_ads( $blog_id );
			} else {
				return true;
			}
		}

	}

	add_action( 'plugins_loaded', function(){
		WPMUDEV_PS_Sidebar_Ads::get_instance();
	}, 10 );

}
?>