Payment Information on hook_commerce_checkout_complete I am developing module which connects Drupal Commerce with 3rd party invoicing system. For this purpose I need to send payment information (has it been paid? how much? in what way?) after the order is complete. I guess the hook_commerce_checkout_complete() hook is the best place to do that but I can't figure out how to obtain this payment information from an $order object/entity.
You can see the payment method the customer selected in the $order->data array, and to determine if the order was paid in full you'd use commerce_payment_order_balance(). Any additional information would have to come from payment transaction entities whose order_id match $order->order_id.