[3.0] Theme split (wave 4, part 18) — give the avatar picker one gallery list and no generated script

[albertlast]

Description

Part of the #7933 split, wave 4.
Profile area.

The gallery was two selects. You picked a directory in the first, and a second appeared
holding its files — filled in by JavaScript from a flat list of every avatar file on the
forum, written into the page:

var files = ["' . implode('", "', Utils::$context['avatar_list']) . '"];
var avatar = document.getElementById("avatar");
var cat = document.getElementById("cat");
var selavatar = "…"; var avatardir = "…"; var file = …;
var size = avatar.alt.substr(3, 2) + " " + avatar.alt.substr(0, 2) + String.fromCharCode(117, 98, 116);

and a second block below generated a swap_avatar() with one case per choice, each case
generated again from which choices the forum allows — about 45 lines of PHP producing about
40 lines of JavaScript to show one <div> and hide three.

There is one select now, with the directories as <optgroup>s, so picking an avatar is
one action instead of two and no list of filenames goes into the page. Each panel carries
data-avatar-choice, and profile.js reads that rather than being told which panels exist.

Two behaviours the old script had are kept:

• focusing a field inside a panel selects that panel's radio (the onfocus attributes)
• switching to Gravatar clears an address left over from one of the other choices — the
  condition for that travels as a data-clear-email attribute instead of being compiled
  into a case

One fix that the single list needs

Profile::getAvatars() marks a file as checked with:

'checked' => $line == Utils::$context['member']['avatar']['server_pic'],

server_pic holds the path (Oxygen/cards.png), $line is the bare name, so a file
inside a directory never came back selected. It did not show before, because the nested
list was built in JavaScript and matched by name there. It compares against the path now.

Utils::$context['avatar_list'] goes with the script that was its only reader.

Checked

Panel switching, both directions, against release-3.0 — identical at every step:

radio	panels shown
on load (none)	none
Gallery	server_stored
My own picture	external
Upload	upload
Gravatar	gravatar
No avatar	none

Gravatar clearing an http://… address on the way in: same both ways. Focusing the
external url field inside its visible panel selects the external radio: same both ways.
Gallery selection updates the preview — Oxygen/cards.png gives
http://localhost:8080/avatars/Oxygen/cards.png with alt="cards" — and there is no
second select left on the page. No console errors from this code.

What could not be exercised

Choosing a gallery avatar and saving it does not work on release-3.0 for reasons outside
this change: the page is a fatal error for any member who has one (fixed separately in
#9440), and even with that fixed the value does not persist, because
User::updateMemberData() cannot turn the bare filename back into a url. So the
pre-selection above is right by construction but cannot be demonstrated until that is
sorted — Avatar::$choice reports none for a prepackaged avatar today, whatever the
column says.

Issues References (Fixes|Related|Closes)

Part of #7933
Related #9440

Co-Authored-By: live627 john@jbrock.us