Phase navigation doesn't make sense on alternative transcripts

[andrewgodwin]

On the new alternative transcripts (for example, CM on Apollo 13), the phase navigation still exists at the bottom of the page, but it doesn't necessarily make sense - for example, there's no content for phases 1 or 8 on a13/CM, and so attempting to click "back" from phase 2 results in a mysterious error.

We first need to decide, from a design standpoint, what to do - drop the arrows if there's no phase that way for this transcript? Switch transcripts to one that does have content? Hide the phase navigation completely?

[jaylett]

While we don't get an error, at the moment this is confusing: hitting back on phase 2 A11 CM just shows phase 2 again but with a different URL. It really needs instead to say "nothing happened in this transcript" or something?

[SteveMarshall]

Agreed, @jaylett. That could be reasonably… interesting to implement, IIRC, because of the way we’re querying redis (everything after timestamp for n items).

[jaylett]

But we can easily check if the first item is outside the phase we're supposed to be in. In fact, wouldn't we run into the same problem if a phase were shorter than the n items we fetch from redis? Or is that covered by the page restriction?