1008 ideal integration online payment provider

[yksflip]

This PR adds the online payment provider mollie as a plugin. User can add credit to their ordergroups balance via various payment methods. wvengen implemented this already in the foodsoft-adams fork. I rewrote some parts to make it work with the newest mollie api version and added some bits to improve the usability.

Changes relevant to the foodsoft core:

• added new attributes to the financial_transaction model to keep track of the state of a transaction
• financial_transaction.value may be nil now, this indicates an incomplete transaction

Changes on the plugin:

• payment_method is no longer choosen in the foodsoft form but on the mollie checkout
• information regarding the transaction fee is displayed
• settings can be configured in the admin screen
• the transaction_type for mollie transactions can be configured in the administration settings

still open

• [ ] move accept_return_to to ApplicationController?
• [x] open currency refactoring issue, implement FoodsoftMollie.currency
• [x] write financial transaction documentation
• [x] reverting a pending financial transaction?
• [x] handle amount < min ?
• [x] squash commits

[wvengen]

p.s. if the amount can be nil in the API, the API docs (swagger) may need updating.

[yksflip]

This is shaping up nicely!

thx! your comment are very helpful :)

[yksflip]

Hey I've been working a bit more an introduced some changes:

• transactions with nil value are no longer revertable
• display payment_state in transaction views
• strong params on api controller
• api-key is now used in function call (around filter didn't work)
• introduce currency config Mollie returns fee amounts always in EUR, no matter what currency is selected. Because of that there is a constraint to charge fees for EUR only.
• introduce default amount config
• some code refactoring

Hopefully I can finish up on this until end of this week :)

[wvengen]

Please let me know when it is ready for review (comment or the re-request review button), as it's been a while. Would be great to have this included in the next release.

[yksflip]

hey @wvengen, thanks for the reminder. I know it's been a while ... I tried to write some documentation, though I don't feel very confident with it. I still don't understand very much of the banking feature. I see this docs as a starting point... I'd happy to hear your feedback and would be great to see this finally merged :)

[yksflip]

thanks for your feedback! I've added some basic model tests for financial_transactions, refactored the search_scope, and implemented the around_save. I also just had a chat with leo and he mentioned the user documentation on https://docs.foodcoops.net/de/documentation/admin/finances

I'll squash the commits later, I thought it could be easier for you to review like this?

[yksflip]

how about this? https://github.com/foodcoops/foodsoft/pull/1031/files#diff-f5c62182c669e1defeb29be1ca2beac61b02af50970b7b8b823708aa855221f7R23

[yksflip]

@wvengen let's merge? :)

[wvengen]

Ah, and for a future PR, it's good to mention the issue number in the PR description (e.g. in this case "Implements #1008"), so that Github recognizes this and provides cross-references. The "1008" in the PR title didn't do this.

[yksflip]

Thank you for also keeping up and your helpful advise :)