Expresso Store 2.0 Discount based on item quantity and {sku} modifier

Question

In order to calculate a discount based on quantity of items in the cart that will take in consideration also the different weight of modifiers (suppose I sell the same product in different containers weighing from 1 to 210kg), I came up with an extension which grabs the $item->$item_qty at every order update, multiplies that value with the $item->sku, adds to the total of Kg being orderd and, based on a table of different discounts hardcoded with conditionals in the extension's php file, calculates the discount to be applied.

I can't seem to pass the $order->$order_discount to the actual order. When I submit the form, the order total doesn't take into account the calculated discount.

Here's my code

<?php  if ( ! defined('BASEPATH')) exit('No direct script access allowed');

/**
 * Store Discount Extension
 *
 * @package     ExpressionEngine
 * @subpackage  Addons
 * @category    Extension
 * @author      Milksamsa
 * @link        http://
 */

class Store_discount_ext {

public $settings        = array();
public $description     = 'Force discount based on item quantity and SKU multiplier';
public $docs_url        = 'http://';
public $name            = 'SKUdiscount';
public $settings_exist  = 'n';
public $version         = '1.0';

private $EE;

/**
 * Constructor
 *
 * @param   mixed   Settings array or empty string if none exist.
 */
public function __construct($settings = '')
{
    $this->EE =& get_instance();
    $this->settings = $settings;
}

// ----------------------------------------------------------------------

/**
 * Activate Extension
 *
 * This function enters the extension into the exp_extensions table
 *
 * @see http://codeigniter.com/user_guide/database/index.html for
 * more information on the db class.
 *
 * @return void
 */
public function activate_extension()
{
    // Setup custom settings in this array.
    $this->settings = array();

    // Add hooks
    $data = array(
        'class'     => __CLASS__,
        'method'    => 'update_cart',
        'hook'      => 'store_order_recalculate_end',
        'settings'  => serialize($this->settings),
        'priority'  => 10,
        'version'   => $this->version,
        'enabled'   => 'y'
    );

    $this->EE->db->insert('extensions', $data);
}

// ----------------------------------------------------------------------

/**
 * Disable Extension
 *
 * This method removes information from the exp_extensions table
 *
 * @return void
 */
function disable_extension()
{
    $this->EE->db->where('class', __CLASS__);
    $this->EE->db->delete('extensions');
}

// ----------------------------------------------------------------------

/**
 * Update Extension
 *
 * This function performs any necessary db updates when the extension
 * page is visited
 *
 * @return  mixed   void on update / false if none
 */
function update_extension($current = '')
{
    if ($current == '' OR $current == $this->version)
    {
        return FALSE;
    }

    $this->EE->db->where('class', __CLASS__);
    $this->EE->db->update(
                'extensions',
                array('version' => $this->version)
    );
}

// ----------------------------------------------------------------------

/**
 * Responds to the store_cart_update_end hook in Exp:resso Store
 * to apply a discount to each product, as needed
 *
 * @return array of cart items
 */
function update_cart($order)
{

    if ($this->EE->extensions->last_call)
    {
        $order = $this->EE->extensions->last_call;
    }

    // Get the number of products currently in the user's cart
     $order->order_discount = 0;
     $total_q = 0;

      foreach ($order->items as $item) {
                $sku = $item->sku;
                $item_q = $item->item_qty * $sku;
                $total_q = $total_q + $item_q; 
            }

     if ($total_q >= 24 && $total_q < 30){
     $order->order_discount = $total_q  * 0.5;
     }

     if ($total_q >= 30 && $total_q < 60){
     $order->order_discount = $total_q  * 0.6;
     }

     if ($total_q >= 60 && $total_q < 100){
     $order->order_discount = $total_q * 0.95;
     }

     if ($total_q >= 100 && $total_q < 200){
     $order->order_discount = $total_q * 1.5;
     }

     if ($total_q >= 200 && $total_q < 210){
     $order->order_discount = $total_q * 1.55;
     }

     if ($total_q >= 210){
     $order->order_discount = $total_q * 1.7;
     }

     return $order_discount;
}
}

/* End of file ext.store_discount.php */
/* Location: /third_party/store_discount/ext.store_discount_batch.php */

//UPDATE

I've followed this procedure: https://gist.github.com/bryantAXS/10882383 Not sure where to go from here. I've not included the calculations for now, for testing purpose I've limited the discount amount to 4.

• I created a new folder in third_party named store_helpers
• I created a new folder in there named store_helpers/classes
• I created a CustomDiscountAdjuster.php class inside it
• I created a ext.store_helpers.php file in third_party/store_helpers

My CustomDiscountAdjuster.php file contains:

<?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 CustomDiscountAdjuster implements AdjusterInterface
{
    public function adjust(Order $order)
    {


        $adjustment = new OrderAdjustment();
        $adjustment->name = "Custom Discount Adjuster";
        $adjustment->type = 'Custom Discount';
        $adjustment->amount = 10;
        $adjustment->taxable = 1;
        $adjustment->included = 1;

        return array($adjustment);



      return array();
    }

}

My ext.store_helpers.php file contains:

<?php  if ( ! defined('BASEPATH')) exit('No direct script access allowed');

/**
 * Store Discount Extension
 *
 * @package     ExpressionEngine
 * @subpackage  Addons
 * @category    Extension
 * @author      Milksamsa
 * @link        http://
 */

class Store_helpers_ext  {

    public $settings        = array();
    public $description     = 'Force discount based on item quantity and SKU multiplier';
    public $docs_url        = 'http://';
    public $name            = 'Store Custom EQ Discounts';
    public $settings_exist  = 'n';
    public $version         = '1.0';

    private $EE;

    /**
     * Constructor
     *
     * @param   mixed   Settings array or empty string if none exist.
     */
    public function __construct($settings = '')
    {
        $this->EE =& get_instance();
        $this->settings = $settings;
    }

    // ----------------------------------------------------------------------

    /**
     * Activate Extension
     *
     * This function enters the extension into the exp_extensions table
     *
     * @see http://codeigniter.com/user_guide/database/index.html for
     * more information on the db class.
     *
     * @return void
     */
    public function activate_extension()
    {
        // Setup custom settings in this array.
        $this->settings = array();

        // Add hooks
        $data = array(
            'class'     => __CLASS__,
            'method'    => 'update_cart',
            'hook'      => 'store_order_adjusters',
            'settings'  => serialize($this->settings),
            'priority'  => 10,
            'version'   => $this->version,
            'enabled'   => 'y'
        );

        $this->EE->db->insert('extensions', $data);
    }

    // ----------------------------------------------------------------------

    /**
     * Disable Extension
     *
     * This method removes information from the exp_extensions table
     *
     * @return void
     */
    function disable_extension()
    {
        $this->EE->db->where('class', __CLASS__);
        $this->EE->db->delete('extensions');
    }

    // ----------------------------------------------------------------------

    /**
     * Update Extension
     *
     * This function performs any necessary db updates when the extension
     * page is visited
     *
     * @return  mixed   void on update / false if none
     */
    public function store_order_adjusters($adjusters) 
    {
      $adjusters[40] = new Store\Adjuster\CustomDiscountAdjuster;
      return $adjusters;
    }

    // ----------------------------------------------------------------------

    /**
     * Responds to the store_cart_update_end hook in Exp:resso Store
     * to apply a discount to each product, as needed
     *
     * @return array of cart items
     */

}

/* End of file ext.store_discount.php */
/* Location: /third_party/store_helpers/ext.store_helpers.php */

Definitely something's going one, since taxes no longer get calculated when store_helpers extension is enabled

Answer 1

When the store_order_recalculate_end hook is fired, all calculations have already taken place. See picture.

So you need to calculate and set the order_total yourself.