feat: Handle deletion and unavailable videos on Youtube

[lfaucon]

It's not very clear yet all the parts of Tournesol that are impacted and should be impacted in the case of a video deleted by the content creator or removed from Youtube for any reason. This nevertheless gives bad user experience, especially if one such video comes up during the tutorial.

1. Understand all the parts of Tournesol that may be impacted
2. Decide what behaviour we want Tournesol to have
3. Plan and execute implementation

[aidanjungo]

Should we detect that automatically or let user signal that?

[lfaucon]

Goal would be automated detection (for example at the same time that we currently refresh a video metadata). If that does not work, then as a last resort letting user signal it, but then we still need trusted moderators to verifies the signals.

[lfaucon]

• First simple solution to investigate and implement: The frontend can find out that the video has been deleted (for example because the thumbnail is missing: https://i.ytimg.com/vi/PN8-fBE50Yg/mqdefault.jpg). Recommendation lists we could collapse the videocard (with a message "deleted video (expand)"). The extension could simply remove the deleted video and show 3 instead of 4 or 11 instead of12 recommendations. (recommended by @jstainer-kleis)

[GresilleSiffle]

We are going to work with @OoIwazaruoO on the <EntityList> to make it display a folded entity card.

What is the expected behaviour after a click on expand? We display the Tournesol and YouTube metadata as usual? I think we may want to not display the video title, because maybe the video was deleted because of its polemic content and the title itself may be polemic too.

How about displaying everything, except the title? The title could be "This video is no accessible anymore".

[amatissart]

If the title is not displayed, and the thumbnail is not available either, is it worth displaying any other metadata at all? The user would not be able to recognize the video, even if they compared it in the past.

In this case, I would just keep a minimal collapsed video card without the possibility to expand it.

[GresilleSiffle]

If the title is not displayed, and the thumbnail is not available either, is it worth displaying any other metadata at all? The user would not be able to recognize the video, even if they compared it in the past.

In this case, I would just keep a minimal collapsed video card without the possibility to expand it.

I'm wondering if we have reasons to even display a collapsed entity card in the recommendations. Is it really useful to know there were an entity that was at this position in the ranking, but now it is not available on YT? We could simplify the recommendations by simply not recommending non available content.

The admin can still see the video in the back end, but not the front end users. We could still display this folded entity card elsewhere, like in the rate-later list, to inform them that what they were about to compare is not comparable anymore.

What do you think @amatissart @lfaucon @aidanjungo @OoIwazaruoO ?

proposition

1. implement a method allowing the front end to detect when an entity is not available anymore.

2. do not display non available entities in the public and individual recommendations.

3. display a folded entity card in the rate-later list, in order to inform the user this video is not available anymore. The only possible action is to delete the video.

4. display a folded entity card in the My compared items page?

5. rework the video analysis page. todo: define what information should appear and not appear.

6. rework the comparison page to prevent comparing non available entities?

[GresilleSiffle]

I took some screenshots to better visualize the recommendations.

---

As a user knowing there was a video here, with an unknown name, that is not available anymore doesn't seem relevant or useful. It can be confusing also because it looks like a title indicating the video above or below is not available.

---

Another capture with this time the poll metadata. It doesn't look very useful too, except if we want the users to be able to go to the analysis page.

[amatissart]

I'm wondering if we have reasons to even display a collapsed entity card in the recommendations. Is it really useful to know there were an entity that was at this position in the ranking, but now it is not available on YT? We could simplify the recommendations by simply not recommending non available content.

Removing the unavailable video from the recommendations page completely at render time could bring some confusion due to how the pagination works: a page with strictly less than 20 is supposed to be the last page. So I think it would still be relevant to display a compact generic message "This video is not available" to keep the pagination consistent with what the user expects.

[GresilleSiffle]

Here is the current state of this feature:

• unavailable videos are folded in all lists (recommendations, rate-later list, and all other pages using <EntityList>)
• unavailable videos are displayed with dark gray overlay in comparisons (all component using <EntitySelector>)

The next steps could be:

• display the dark gray overlay on the comparisons page (instead of the thumbnail returned by YT, see capture (a))
• decide how to handle unavailable videos in the tutorial
• decide how to handle unavailable videos on the home page comparison
• maybe more

capture (a)

[lfaucon]

The next steps could be:

• display the dark gray overlay on the comparisons page (instead of the thumbnail returned by YT, see capture (a))
• decide how to handle unavailable videos in the tutorial
• decide how to handle unavailable videos on the home page comparison
• maybe more

Based on impact, priotities should be (1) hide unavailable videos in the extension recommendations (2) reload in tutorial suggestions (3) reload in home page comparison (...last) comparison page

[GresilleSiffle]

I move the issue from In progress to Selected because no one is currently working on it.

[tbrnd]

@GresilleSiffle @lfaucon I'll take care of (1) if nobody is working on this already

[GresilleSiffle]

No one is working on it as far as I know : )