A timezone which leads to "day-wrapping" seems to confuse the timetable rendering code

[pferreir]

Describe the bug

This happened in an event happening in Europe/Zurich as seen in Asia/Seoul.

e.g.

becomes:

Which seems OK, only that the second day is incorrectly rendered:

(that last green block should have been at midnight)

In detailed view things get even worse:

becomes:

(these should be on Tuesday, not here) [plus, further down the page...]

(only this last part is correct)

To Reproduce Steps to reproduce the behavior:

1. Open https://indico.cern.ch/event/1016060/timetable/#20210510;
2. Set your timezone to Asia/Seoul;
3. You will notice the timetable is a bit of a mess.

Expected behavior

The time should be offset of 7h, with the "first day" of the event starting at 21:00 and finishing already on Tuesday (at 1:10 local time). The last two talks of the day should be shown on the day after.

Additional context Reported at CERN, through INC2786935

[pferreir]

Possible duplicate of #3073?

[pferreir]

Ok, I gave it 1h of my time and the conclusion is that the cost of fixing the logic in the rendering code would be too high at this point. I'd prefer that we focus our resources on coming up with a new version of the timetable in 2022.

[pferreir]

Closing in favour of #3073