Skeleton plugin for handling discounts in Event Organiser Pro

bulk-discount.js

jQuery(document).ready( function($) {
		
	wp.hooks.addFilter( 'eventorganiser.checkout_cart', function( cart ){
		
		var total = cart.total; //total amount
		var quantity = cart.quantity; //quantity of tickets
    
		//Calculate amount to be discounted:
		var discount = 0;
		
		if( discount ){
			cart.total = total - discount
			$('.eo-booking-bulk-discount-row').hide();
			return cart;
		}
		$('.eo-booking-bulk-discount-row').show();
		return cart;
	}, 5 );

} );

bulk-discount.php

<?php
/*
Plugin Name: Event Organiser Bulk Discounts
Plugin URI: http://www.wp-event-organiser.com
Version: 0.1.0
Description: Bulk discounts for Event Organiser bookings
Author: Stephen Harris
Author URI: http://www.stephenharris.info
*/

//Initiates the plug-in
add_action( 'plugins_loaded', array( 'EO_Discount_Codes', 'init' ) );	

class EO_Bulk_Discount{

	/**
	 * Instance of the class
	 * @static
	 * @access protected
	 * @var object
	 */
	protected static $instance;

	/**
	 * Instantiates the class
	 * @return object $instance
	 */
	public static function init() {
		is_null( self :: $instance ) AND self :: $instance = new self;
		return self :: $instance;
	}

	public function __construct() {
		
		//Register scripts
		add_action( 'init', array( $this, 'register_scripts' ) );
		
		//Add discount row
		add_action( 'eventorganiser_booking_pre_total_row', array( $this, 'insert_discount_row' ), 5, 2 );
		
		//Calculate and store discount amount
		add_action( 'eventorganiser_new_booking',  array( $this, 'store_discount_amount' ), 4 );
		
		//Apply discount
		add_action( 'eventorganiser_get_booking_meta_booking_amount', array( $this, 'apply_discount' ), 400, 2 );
		
		//Add discount row to email
		add_action( 'eventorganiser_email_ticket_list_pre_total', array( $this, 'add_to_email' ), 400, 2 );
		add_action( 'eventorganiser_get_booking_table_for_email_pre_total', array( $this, 'add_to_email' ), 400, 2 );
		
		//Add to PayPal
		add_filter( 'eventorganiser_pre_gateway_checkout_paypal', array( $this, 'add_to_paypal_cart' ), 10, 2 );
	}
	
	/**
	 * Register javascript and stylesheets
	 */
	function register_scripts(){
		wp_register_script( 
			'eo_bulk_discount_script', 
			plugin_dir_url(__FILE__ ). "bulk-discount.js", 
			array( 'eo_pro_occurrence_picker' )
		);
	}

	/**
	 * Adds discount row to the ticket picker & enqueues scripts
	 * 
	 * @param string $html
	 */
	function insert_discount_row( $html ){

		//Get currency symbol
		$currency = eventorganiser_pro_get_option( 'currency' );
		$symbol = eventorganiser_get_currency_symbol( $currency );
		$placeholder = ( eventorganiser_pro_get_option( 'currency_position' ) == 1 ? '%1$s%2$s' : '%2$s%1$s' );

		//'Discount' row
		?>
		<tr class="eo-booking-bulk-discount-row" style="display:none;">
			
			<td><strong> <?php esc_html_e( 'Discount:', 'eventorganiserbd' ); ?></strong></td>
			
			<td> 
				-<?php printf( $placeholder, $symbol, '<span id="eo-booking-discount"></span>' ); ?>
			</td>
			
			<td></td>
			
		</tr>
		<?php

		//Enqueue scripts
		wp_enqueue_script( 'eo_bulk_discount_script' );
	}
	
	/**
	 * After a booking is made calculate the discount amount.
	 * 
	 * Calculates & stores the discounted amount with the booking
	 * @param int $booking_id
	 */
	function store_discount_amount( $booking_id ){

		//Ticket quantity and non-discounted price
		$amount = floatval( eo_get_booking_meta( $booking_id, 'booking_amount', true )  );
		$ticket_quantity = floatval( eo_get_booking_meta( $booking_id, 'ticket_quantity', true )  );
    
		$discount_amount = 0;
		
		//Calculate amount to discount, store it i $discount_amount
		update_post_meta( $booking_id, '_eo_booking_bulk_discount_amount', $discount_amount  );
	}

	
	/**
	 * If a discount was used for the booking, removes this from the booking total
	 * @param float $amount The booking total (pre discount)
	 * @param int $booking_id
	 * @return float $amount The booking total (post discount)
	 */
	function apply_discount( $amount, $booking_id ){
		$discount_amount = get_post_meta( $booking_id, '_eo_booking_bulk_discount_amount', true );
		if( $discount_amount && floatval( $discount_amount ) > 0 ){
			$amount = max( 0, $amount - floatval( $discount_amount ) );
		}
		return $amount;
	}

	
	/**
	 * Add a 'Discount' row to bookee / admin emails
	 *
	 * @param string $rows HTML of rows to insert just prior to 'total' row
	 * @param int $booking_id Booking ID
	 * @return string HTML of rows to insert just prior to 'total' row
	*/
	function add_to_email( $rows, $booking_id ){
		$discount_amount = get_post_meta( $booking_id, '_eo_booking_bulk_discount_amount', true  );
		if( $discount_amount && floatval( $discount_amount ) > 0 ){
			$rows .= sprintf(
					'<tr> <td>%s</td> <td>%s</td> <td></td> </tr>',
					__( 'Discount', 'eventorganiserdc' ),
					eo_format_price( floatval( $discount_amount ) )
			);
		}
		return $rows;
	}
	
	
	/**
	 * Adds the discount to PayPal's itemised cart.
	 *
	 * Sets the 'tax_cart' attribute of the cart.
	 * @param array $cart
	 * @param array $booking array
	 * @return array
	*/
	function add_to_paypal_cart( $cart, $booking ){
		$discount_amount = eo_get_booking_meta( $booking['booking_id'], 'bulk_discount_amount', true );	
		if( $discount_amount && floatval( $discount_amount ) > 0 ){
			$cart['discount_amount_cart'] = $discount_amount;
		}
		return $cart;
	}
		
}