Update existing events instead of replacing them

[luhuhis]

Hi,
is it possible to add functionality such that events are updated when they've changed, instead of always deleting/creating all?
The problem with the latter is that if you merge into a calendar that is subscribed to by other people (who may have email notifications turned on), then that can easily lead to your gmail account sending out hundreds of emails, which you have no control over.

The events should by identifiable by their respective event ids, should they not?

Of course you would need to loop over all events in the specified time frame of the calendar you want to merge into.

[luhuhis]

For each source event one can just copy the iCalUID as well. By checking for this ID and the special character one can ensure that events are uniquely matched into source-target pairs.

[dominikbullo]

+1

[hamon-e]

Because I spend way to much time updating this, here is my version of it

https://gist.github.com/hamon-e/d5a653a5ae7865e45ca90cb81252ec1b

solve a few problems with iCalUID (recurring events have the same iCalUID but different ids (id = iCalUID + "_" + date + "z"), BUT when we are the ones creating an event id can't contains _ or z)
https://gist.github.com/hamon-e/d5a653a5ae7865e45ca90cb81252ec1b#file-gistfile1-gs-L193

do not update events if not needed

add all the events, remove the if true if not wanted
https://gist.github.com/hamon-e/d5a653a5ae7865e45ca90cb81252ec1b#file-gistfile1-gs-L145

added a color system to recognized the source of the events
https://gist.github.com/hamon-e/d5a653a5ae7865e45ca90cb81252ec1b#file-gistfile1-gs-L8