Need help with group discount + restricted coupon

[abcisme]

I'm having some trouble achieving the correct calculations with my order total modules.

We have a discount group that gets 3% off all orders.

I have set up a $10 coupon that is valid only on one product, with no minimum purchase.

If I restrict the coupon to the product, it calculates $10 minus the group discount, instead of applying the full $10.

Example:

Product A $10.00
Product B $1.00
Coupon restricted to product A

Order total shows:

Sub-Total: CDN $11.00
Group Discount - 3%: -CDN $0.33
Discount Coupon: wy487nwb: -CDN $9.67
Warehouse Pickup: CDN $0.00
13% Tax (ON): CDN $0.09
Total: CDN $0.76

Why is the coupon deducting the group discount from the coupon amount?

If I remove the restriction, the coupon applies correctly.

My order total modules sort order:
100 Sub-Total
102 Group Discount
103 Discount Coupon
200 Shipping
300 Tax
310 Gift Certificates
900 Total

[abcisme]

Also, if the group discount is larger than $10, it won't allow you to apply the coupon at all.

[abcisme]

I can't reorder the group discount to apply after the coupon, because then any percentage coupons are calculated on the full subtotal instead of the subtotal minus the group discount. I guess I'm kind of stuck.

In a perfect world, what *should* happen is that restricted dollar amount coupons should be applied to the product price minus the group discount. NOT the entire subtotal minus the group discount. I'm sure that's not something that would be an easy fix though...

[abcisme]

What I'd like to try is to change the code so that when the coupon is for a dollar amount AND there is more than one product, the coupon will ignore the group discount. Can anyone help?

I'm assuming it would be in this function?

 /**
   * Method used to produce final figures for deductions. This information is used to produce the output<br>
   * shown on the checkout pages
   *
   */
  function process() {
    global $order, $currencies;
    $order_total = $this->get_order_total();
    $od_amount = $this->calculate_deductions($order_total['total']);
    $this->deduction = $od_amount['total'];
    if ($od_amount['total'] > 0) {
      reset($order->info['tax_groups']);
      $tax = 0;
      while (list($key, $value) = each($order->info['tax_groups'])) {
        if ($od_amount['tax_groups'][$key]) {
          $order->info['tax_groups'][$key] -= $od_amount['tax_groups'][$key];
          $tax += $od_amount['tax_groups'][$key];
        }
      }
      if ($od_amount['type'] == 'S') $order->info['shipping_cost'] = 0;
      $order->info['total'] = $order->info['total'] - $od_amount['total'];
      if (DISPLAY_PRICE_WITH_TAX != 'true') {
        $order->info['total'] -= $tax;
      }
      $order->info['tax'] = $order->info['tax'] - $tax;
      //      if ($this->calculate_tax == "Standard") $order->info['total'] -= $tax;
      if ($order->info['total'] < 0) $order->info['total'] = 0;
      $this->output[] = array('title' => $this->title . ': ' . $this->coupon_code . ' :',
                              'text' => '-' . $currencies->format($od_amount['total']),
                              'value' => $od_amount['total']);
    }
  }
  /**

[abcisme]

What I need is:

If the coupon type is 'F' (flat amount)
AND there is more than 1 product in the cart
AND the customer is in a discount group
THEN the coupon = the full coupon amount up to 100% of the subtotal price

I think I would need to change this code... But not sure how.

} elseif ($coupon->fields['coupon_type'] == 'F') {
            $od_amount['total'] = round($coupon->fields['coupon_amount'] * ($orderTotal>0), 3);
            $od_amount['type'] = 'F';
            $ratio = $od_amount['total']/$orderTotal;
          }

[Ajeh]

What happens if you change the Modules ... Order Total ... sort orders to the defaults:

100 Sub-Total
102 Group Discount 290
103 Discount Coupon 280
200 Shipping
300 Tax
310 Gift Certificates 840
900 Total