Mention Zones and Endpoints Config

[hefan]

like discussed in #57

[kennyadsl]

Merging, the CI failures are not related.

FYI: with @vassalloandrea we tried to investigate the difference between country and zone in the Klarna context and we think there's some changes to do on the extension:

• zone needs to be a preference on the payment method because it determines which endpoint it will be used for the Klarna account. In case there's a need for multiple zones for a store, the store needs to create multiple Klarna accounts and so, multiple payment methods.
• country should not be a preference: it will be used by Klarna to determine the payment methods to display in the payment page, so it's better to take it from the user's address (still not sure if billing or shipping address).

We will work on this in the next days, but please let me know if this makes sense for you as well @hefan. 🙏

[hefan]

yes, this seems reasonable. I guess the country preference is used only for the backend validation test?

Because at the storefronts payment screen there already appears a message if the country of the buyer address is not available at klarna. i guess there will be constraints regarding the Orders currency/country combination as well.

Here is the list of available countries, locales, and currencies at klarna.
https://docs.klarna.com/klarna-payments/in-depth-knowledge/puchase-countries-currencies-locales/

[kennyadsl]

It seems like at the moment the country is used as a fallback in case there's no s billing or shipping address, when we serialize the order to send to Klarna. I think that's how Klarna understands which payment methods to display.

[hefan]

ok. so this means it is reasonable to leave the country as a preference, maybe slightly rename it.