Creating a Store adjuster

DeliveryAdjuster.php

<?php

// Inside our custom third_party addon folder, /third_party/store_helpers, we have a folder called "classes."
// Within the classes directory we have this file, which holds our custom build Adjuster Class.
//
// You should be able to see how this class is passed our $order object, and then instantiates a new 
// Order Adjustment object, which we use to make the adjustment. There are a few properties on the Order Adjustment
// object (nane, type, amount, etc..) that define the adjustment. The adjustment is then returned and processed.
 

namespace Store\Adjuster;

require PATH_THIRD.'store'.'/autoload.php';

use Store\Model\Order;
use Store\Model\OrderAdjustment;

/**
 * Calculate handling surcharge applicable to an order
 */
class DeliveryAdjuster implements AdjusterInterface
{
    public function adjust(Order $order)
    {
      if($order->order_custom1 == "delivery"){

        $adjustment = new OrderAdjustment();
        $adjustment->name = "Delivery Charge";
        $adjustment->type = 'Delivery';
        $adjustment->amount = 4;
        $adjustment->taxable = 0;
        $adjustment->included = 0;

        return array($adjustment);

      }

      return array();
    }

}

ext.store_helpers.php

// Create an extension (ours is called Store Helpers), and create a hook for the 
// store_orders_adjuster method, which Store provides.
//
// Inside the method your going to be loading the custom Adjusters you need, which are included in a seperate file.
// In this example I have two custom adjusters, for two seperate adjustments to the order.

public function store_order_adjusters($adjusters)
{
  $adjusters[40] = new Store\Adjuster\DeliveryAdjuster;
  $adjusters[50] = new Store\Adjuster\TipAdjuster;

  return $adjusters;
}