@Romuald_Pochet Thanks for your PR!
I see that you’ve gone with this for development:
Before even talking about the code, I think it would be good if we agree on what we want at the feature level, because in my opinion there are many ways to do this, and it’s not a simple feature:
- Typically, the « event starts » trigger is useful, but often what we want is « event starts in 5/15/30 minutes » (if you want to receive a reminder 15 minutes before leaving for an appointment, for example). Knowing that this is a very different paradigm, it will change the implementation a lot (since you have to program each trigger and not each event), so you need to think about it beforehand.
- As for event selection, how does it work? Is there a list and you select an event from the list? Do you take all events that contain this string? In my opinion, there is a real reflection to be had on this, it may be useful to have a trigger that is triggered on a specific event, or on a match of a specific text, in any case it must be clear in the UI.
- Who has the right to see which calendars? This is a very hot topic, we are talking about it here with @bertrandda: [Caldav] Configuration multicomptes - #13 par pierre-gilles. We need to agree before doing this dev.
Sorry if I’m asking a lot of questions, it’s a really cool feature and if we want to meet everyone’s needs, we need to ask the questions beforehand! 
Thanks anyway for starting the development @Romuald_Pochet, it’s great work anyway 