The thing is that you can probably use libofa to get a fingerprint of the audio file, but if the file has no PUID available, you will be stuck and will have to use something like genpuid to submit the audio fingerprint to AmpliFIND and wait about a day to get a PUID.
That being said, I tried something similar about two years ago, but kinda lost interest in the project when I failed to write the IDv3 tags, if I remember correctly. However, the source code is available on Bitbucket.
I basically wrapped libofa using a DllImport
and also wrapped genpuid (ie. read the output XML) to be able to read the fingerprint and submit the file for fingerprinting if I did not get one from libofa. I also wrote some code that reads information from MusicBrainz using MusicBrainz Sharp.
Well, at least that was what I planned back then, I think. :) I hope this helps you to solve your problem and I'd love to see an update on this.
Edit: I just noticed that I created a bug report for myself, which basically says that I still needed an implementation for my decoder which is probably why I created this question in SO. So I guess I did not implement the genpuid fingerprinter just to be able to do the fingerprint/get the guid, because I did not get the libofa fingerprinter to work correctly.