Is it possible (or difficult) to migrate an entire forum from vanilla to a lemmy instance?

As per the title.

If I was running a Vanilla forum and wanted to migrate over to a new lemmy instance, e.g. forum.com to lemmy.forum.com Could I migrate the entire forum over while keeping the same categories/sub categories as communities I guess, and bringing all of the old threads with them? If it is possible, would it be difficult?