// Profile pictures. A user either has one (the server says so with an
// avatar_version, which is also the cache buster in the image URL) or shows
// their initial in a coloured circle, as before.

const versions = new Map(); // user id -> avatar_version

// Learn from a user list (or a single user) which people have a picture.
export function noteAvatars(list) {
  for (const u of list || []) setAvatarVersion(u.id, u.avatar_version);
}

export function setAvatarVersion(userID, version) {
  if (version == null) versions.delete(userID);
  else versions.set(userID, version);
}

export function clearAvatars() {
  versions.clear();
}

// withAvatar lays the person's picture over el, which keeps its initial
// underneath: if the image fails to load, the initial is what shows.
export function withAvatar(el, userID) {
  const v = versions.get(userID);
  if (v == null) return el;
  el.classList.add('has-img');
  const img = document.createElement('img');
  img.className = 'avatar-img';
  img.alt = '';
  img.decoding = 'async';
  img.src = `/api/users/${userID}/avatar?v=${v}`;
  img.addEventListener('error', () => img.remove());
  el.append(img);
  return el;
}