Feature request: Local timezone

[torotil]

It’s a bit of a inconvenience to need to take care of time zones when creating the data for the YAML files. Even more so because dance events are usually in person at a specific place where the timezone to use is kind of obvious

I’d propose to …:

1. Move the timezone information to an extra field.
2. Accept unix locales (eg. Europe/Vienna) for this field instead of just offsets.
3. Implement a mapping of country/city to default timezone.

Any of those would improve the editing experience.

[qwandor]

Those seem like reasonable ideas, I'll have a go at implementing them. The change is going to require changing all existing files though, which is a pain.

[qwandor]

I've started looking into this, and unfortunately daylight savings time boundaries make it tricky.

Just moving the timezone offset to a field by itself doesn't work, because sometimes an event will run over a DST boundary, e.g. from 2024-03-30T20:00:00+00:00 to 2024-03-31T04:00:00+01:00, where the start and end UTC offsets are different. Having a separate field with the timezone name rather than the offset (e.g. Europe/London in this example) almost works, except that there are some times right on the boundary that are ambiguous (and some that don't exist at all). E.g. 2024-10-27T01:30:00 in Europe/London refers to two different times, either before or after the offset change. It's unclear how to handle this. I could always pick one, but that makes it impossible to correctly enter events starting or ending within a particular hour each year.

Your third suggestion of mapping cities to default timezone is possible (as part of the add event form), though is more of a pain without timezone names being stored in events.

[torotil]

Ok, I see the edge cases 🤔

Would it be an option to still allow the start and end time to specify an offset? Then this could be used to disambiguate the rare edge cases while still not needing to care for almost all events. So my suggestions would just be a fallback for when there is no offset specified. This would also remove the need to migrate existing files.

NB: As an organiser I would expect half of my audience to just understand the wrong time in those cases anyway — even if I list the time in an unambiguous way. 😂

[qwandor]

#315 is now live, https://folkdance.page/add will automatically set the timezone based on the country and state.