Add diga invoice correction

[gtuk]

Pull Request

Description

This PR (WIP in order to gather more feedback) adds the possibility to send diga invoice corrections as described in "Technische Anlage 1" https://www.gkv-datenaustausch.de/media/dokumente/leistungserbringer_1/digitale_gesundheitsanwendungen/technische_anlagen_aktuell_7/DiGA_Anlage_1_Technische_Anlage_zur_RL_V2.0_20230510.pdf and "Anhang 8" https://www.gkv-datenaustausch.de/media/dokumente/leistungserbringer_1/digitale_gesundheitsanwendungen/technische_anlagen_archiv_8/DiGA_Anhang8_Rechnungskorrekturen_V1.1.0_20230413.pdf

The idea is to have a separate class (similiar to DigaInvoice) in order to not interfere with the existing implementation.
In the DigaApiClient two new methods (digaInvoiceCorrection and digaTestInvoiceCorrection) are exposed that take the DigaCorrectionInvoice class as a parameter.
The request payload is build inside DigaXmlJaxbRequestWriter and is reusing as much functions as possible from the existing implementation for billing.

Feel free to share ideas / opinions / feedback regarding the current state of the implementation

Open

• Tests

[fongie]

Thanks @gtuk ! I will review soon (possibly next week though)

[fongie]

Thanks for adding this feature!

Functionally the implementation looks great, but I have some thoughts about the code design.

First of all, I think I agree with your decision to expose a new method for corrections only in the public contract. In practice, when it comes to corrections I think you wouldn't be doing those automatically as part of your application's logic very often, but rather on a manual basis or possibly with some internal tooling. As such I think it makes a lot of sense to have a separate method for it.

On the other hand, there are so many things in common between the invoicing methods right now, that we have quite a lot of duplicated code in DigaApiClient and in the two invoice types. I think this indicates that they are similar enough that we should be able to handle them both through the invoiceDiga API.

In summary, I think I would like to do this:

• have DigaCorrectionInvoice extend DigaInvoice and add the new fields only (remember to use SuperBuilder annotation for builder to work)
• in performDigaInvoicing, change
  var xmlInvoice = xmlRequestWriter.createBillingRequest(invoice, billingInformation);
  to
  var xmlInvoice = invoice instanceOf DigaCorrectionInvoice ? xmlRequestWriter.createInvoiceCorrectionRequest(invoice, billingInformation); : xmlRequestWriter.createBillingRequest(invoice, billingInformation);
• keep the digaInvoiceCorrection method but just have it call invoiceDiga

Unless I'm mistaken those changes will be enough to accomplish this and still have the rest of your feature work the same. I think it will be easier to keep track of the invoicing logic by doing it in one place, and I'm not that worried about it interfering with any working code 😃

What do you think? I'm open to discussion on this!

[gtuk]

@fongie thanks for the great feedback. I incorporated all the changes (although i'm not really sure about the casting to DigaCorrectionInvoice when calling the createInvoiceCorrectionRequest method)

[fongie]

Nice, I think it all looks good now! Just some doc on the main class, and maybe a suggestion on the cast since you mentioned it, and we'll be good to go with this!

[fongie]

looks good now I think! do you still consider it WIP or is it ready to be released @gtuk ?

[gtuk]

looks good now I think! do you still consider it WIP or is it ready to be released @gtuk ?

From my side it would be ready

[fongie]

Released in 2.1.0! 🎉 https://github.com/alex-therapeutics/diga-api-client/releases/tag/2.1.0