Copy calender events from calender A to B without duplicates?

Background: I subscribe to my Facebook calender in the Calender application on my computer. There are two problems with this:

  1. It only keeps the last 30 days
  2. It is not writeable/editable and sometimes events are setup really stupid on Facebook, e.g., 24 hours a day for two weeks (rather than all day events) which makes the visual presentation quite useless. Besides, I often only is interested in the first day of such an event (e.g. the opening night of an art exhibition

I therefore want to run a script once an hour or so that copies all new events from my FB-calendar to a regular calender that keeps all events forever (so I easily can go back and find an old event) as well as edit events according to point 2 above.

Before I start doing this I wonder if Calender supports my use case in a smart way?

A. I think events have a UUID (that is set by Facebook in my case). I also think that easiest for me would be to just copy all events from the FB-calendar to my destination calender and let handle duplicates based on that UUID, wouldn’t it? But does that work?

B. If A is fine, what happens with the UUID if I edit an event in the destination calendar - does the UUID change or does it remain the same?

Hi. Upon an event being copied, its unique ID transfers. I don’t know if subsequent same-ID transfers would fail for extant items or actually replace those with exact duplicates, but either scenario appears to happen silently and one outcome should be indistinguishable from the other. Hourly duplication sounds excessive, and, if the event count is high, is likely to destabilize the app, which is fairly buggy.