Offline payment empty observer

Question

Im trying to do an offline payment where my customer wants to "payonbill". All works fine and i added this snippet:

 <config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="urn:magento:module:Magento_Store:etc/config.xsd">
    <default>
        <payment>
            <checkmo>
                <active>1</active>
                <model>Magento\OfflinePayments\Model\Checkmo</model>
                <order_status>processing</order_status>
                <title>Check / Money order</title>
                <allowspecific>0</allowspecific>
                <group>offline</group>
                <payment_action>authorize_capture</payment_action>
            </checkmo>
        </payment>
    </default>
</config>

The problem however exists where i have to connect some stuff once a payment is receive for certain products. I do this with an observer on sales_order_invoice_pay

Thing is that the event is thrown for the offline payment however the event is empty. What can i do to resolve that? Or is there a better way to approach this scenario? At this moment i am receiving the orderId in the observer and continue from there.

/**
 * Execute observer
 *
 * @param Observer $observer
 * @return void
 */
public function execute(
    Observer $observer
) {
    $invoice = $observer->getEvent()->getInvoice(); ## This is empty
    $order = $invoice->getOrder();
}

In above example is when the offline payment is done. With an online payment all works fine.

Best,

Pim

Answer 1

Get the payment model from the order, then get the method instance from the payment:

    $invoice = $observer->getEvent()->getInvoice();
    $order = $invoice->getOrder();
    $payment = $order->getPayment();
    $method = $payment->getMethodInstance();
    $methodTitle = $method->getTitle();

Where $order is an instance of Magento\Sales\Model\Order.

Answer 2

I fixed the issue by actually removing the stuff i previously did and by implementing this module:

https://github.com/dominicwatts/autoinvoice

The actual problem was that all was working fine but in the end for the offline payment the invoice is generated when booking it inside admin. Bypassing the status won't generate the invoice for you.