Send "stable" amount based on fiat currency

[rolznz]

Some people want to send an amount in fiat. If they choose a fiat currency we can do the conversion for each payment. Related to #35

[hvoecking]

I would also be interested in this feature. I'd even attempt an implementation, but I have no experience in this project yet, so no idea how ambitious my approach would be, but if I have some time I'll look into it

[rolznz]

@hvoecking this is difficult because ZapPlanner is designed to work with a budgeted NWC connection. Currently there is no implementation that supports fiat budgeting, which could cause connection to have more (giving ZapPlanner access to more funds than necessary) or less (inability to make the payment).

In order to do this I think either:

• The user accepts to give a larger budget in sats (e.g. 50%) to allow for short-term price volatility - but maybe this is ok.
• NWC budgets support fiat amounts e.g. in Alby Hub. I doubt this will be implemented though as it seems to increase complexity a lot. CC @bumi

[matjaz]

I think first option is enough.

[matjaz]

More important is to get notified of a failed schedule and retry mechanism.

[rolznz]

@matjaz you will get automated emails from Alby Hub as long as you connect your Alby Account, so that should be ok!

[rolznz]

Regarding retries: I think if ZapPlanner fails, it will wait a month before it retries (or however long the normal payment interval is). 🙈

If it fails 3 times, it will stop retrying.

[matjaz]

Connection/friend should receive an notification/email, not node owner.
Maybe add email to friends and family connection.