Beautiful work, but the cup can't hold water (or tea, or wine) now I assume? So a partial restoration. It does make me wonder if you could do a mechanical repair like that and then reglaze and refire it (but I suppose that'd melt most metalwork soft enough to hammer onto a delicate cup...)

Youtube video posted in a comment above shows that it does hold liquids! https://www.youtube.com/watch?v=aGHkigtPcIA