I have a potential idea. What if for an auto-activity setup, you made a fleet of bot NNIDs, and it monitored everyone’s status on games and their friend codes and stuff, and bam! Auto-set status!
It might make sense at first, but it wouldn’t be feasible, I would need multiple consoles to do this, as you can only have one nnid logged in per console at the same time, it applies to both 3DS and Wii U, and as far as I know you can only see the status of those on your friend list, and both consoles have a limit of 100 friends per account, so you can imagine where this is going…
The most practical solution would be to allow each user to authenticate with their own account and use their information for this purpose, but the problem with this (as mentioned in the description) is that I would still need to have access to the Nintendo Network API to make this possible, homebrew alternatives that don’t rely on online services are totally possible and already exist (at least for the Wii U), but none of them are fully compatible with all games.
My hope is that in the future I can implement a simple and clean auto-activity setup using Pretendo Network, which is an open source alternative to Nintendo Network, although it is still under development at the moment.