At nostr:npub1pu3vqm4vzqpxsnhuc684dp2qaq6z69sf65yte4p39spcucv5lzmqswtfch we did some similar work on top of your library for a probably incomplete version of Nip-17 but it may be useful anyways https://github.com/planetary-social/nos/blob/aebbcb7353ec5cc34584bc3c802ddb6b754cb6ad/Nos/Service/GiftWrapper.swift