Business/Working Hours - Any existing packages I've not managed to find?

I try and avoid anything semi-serious do with dates, times and timezones where possible after having been stung by that in the past, and I was hoping that there was some kind of business hours/working hours package that I’ve missed (I’ve had a good search through hex, google, etc.) - even if it’s an erlang one.

Anyone aware of anything? :slight_smile: Before I go away and implement something myself… :sweat:

Edit: Just to clarify I’m thinking about something along the lines of, or which will allow me to take a given date (probably in UTC), add an interval of time, but only taking into account working hours (i.e. working hours at 9-5, at 4:30 add 2 hours, results in 10:30 next morning)