Change file name by segments, looking for a "signal"

[caarpore]

I share songs from other family members, unfortunatly, no all of us are using the same code to identify songs, because I use a consecutive number, separated by a " - ", arthis, separeted again for a " - ", and the name of somg. Others use only name of songs, separated by a " - " and name of arthist. If I can do a massive change to convert "song name - arthist" to "arthist - song name" will be a big help for me and I think many others that has the same clasification on songs.