Ok, I have been playing with this. First off, it is not a an AwoCoupon or Onepage issue, it is a Virtuemart issue. Can produce the error with shipping without AwoCoupon or Onepage enabled and using Virtuemart coupons.
In Virtuemart > configuration > checkout, setting 'Enable Automatic Selected Shipment' to 'None' triggers this strange behavior. So in your configuration, I have changed it to 'No preference'. At least now you can check out.
Also in doing it this way, it does not really take the coupon discount into account when calculating the min_amount / max_amount of shipping. When virtuemart calculates the shipping to use, it does not seem to have the coupon data.
I wrote some code that can do this specifically for AwoCoupon, but it does require adding code to the core of Virtuemart
In the file www/administrator/components/com_virtuemart/plugins/vmpsplugin.php, around line 960 is this:
<?php
if(empty($method->min_amount)) $method->min_amount = 0.0;
if(empty($method->max_amount)) $method->max_amount = 0.0;
$amount = $this->getCartAmount($cart_prices);
?>
Right after that add this:
<?php
if ( empty( $cart_prices['salesPriceCoupon'] ) ) {
if ( class_exists( 'awocoupon' ) ) {
$coupon_session = AC()->storediscount->get_coupon_session();
if ( ! empty( $coupon_session->product_discount ) ) {
$amount -= $coupon_session->product_discount;
}
}
}
?>
The above code checks to see if there is a coupon processed within AwoCoupon, if so, subtract the product part of the discount from the total used to calculate min/max amount ranges.
