Fix the video duration not being shown on thumbnails on the
https://danbooru.donmai.us/comments page.
BUG: this introduces duplicate HTML ids on the comments page. Post
thumbnails and post comment containers both have the same html ID.
Previously thresholded comments were hidden completely. You had to click
the "Show X hidden comments" button to unhide all hidden comments in a
thread. Now it works like this:
* When a comment is below your threshold, the comment text is hidden and
replaced by a `[hidden]` link, which you can click to unhide the comment.
* When a comment is at half your threshold (for example, your threshold
is -8 but the comment is at -4), then the comment is greyed out.
This means that comments aren't completely hidden, they're just
collapsed, so you can see the commenter and the score without unhiding
the comment. It also means you don't have to scroll back up to unhide a
comment, and threads aren't disrupted by comments being secretly
hidden (which is confusing when people are replying to hidden comments,
which forces you to go back up and unhide to find).
Refactor the post preview html to use the ViewComponent framework. This
lets us encapsulate all the HTML, CSS, and helper methods for a UI
component in a single place.
See https://viewcomponent.org.
* Fix inconsistencies in how wiki pages were linked.
* Link directly to the wiki instead of to a title search that is expected
to redirect to the wiki.
Comments have three states: visible, hidden, and invisible. Visible
comments are always shown. Hidden comments are not shown until the user
clicks 'Show all comments'. Invisible comments are never shown to the
user. Deleted comments are treated as hidden for moderators and
invisible for normal users. Thresholded comments are treated as hidden
for all users.
Certain parts of comment rendering triggered sql queries that we didn't
really need to do. Rework things to avoid this.
* Preload comment creators in order to display commenter names with link_to_user.
* Preload comment votes in order to display "undo vote" links. Only preload
votes for members since anonymous users can't vote and don't have "undo
vote" links.
* Rework various conditionals to do the filtering in Ruby so that we
avoid issuing any extra queries in sql.
* Avoid issuing any queries at all when the post doesn't have any
comments (when last_commented_at is blank).
