// Who has a note open. Each editor gets a name and a color when its socket connects; both are// kept on the socket itself (see NoteRoom), never in storage, so the list is always exactly the// open connections. See decision 0003 in the knowledge base.import type { Editor, ServerMessage } from "./protocol.ts";export const NAMES = ["Otter", "Heron", "Lynx", "Wren", "Badger", "Puffin", "Marten", "Ibis", "Stoat", "Finch", "Hare", "Newt"];// Picked to stay readable as text and as a dot on a light or a dark page.export const COLORS = ["#0f766e", "#b45309", "#7c3aed", "#be123c", "#1d4ed8", "#4d7c0f", "#a21caf", "#0e7490"];// A name and a color for a new editor, preferring ones nobody here is using. Past twelve// editors names repeat with a number ("Otter 2").export function pickEditor(here: readonly Editor[], id: string): Editor {  const names = new Set(here.map((e) => e.name));  const colors = new Set(here.map((e) => e.color));  let name = NAMES.find((n) => !names.has(n));  for (let round = 2; !name; round++) name = NAMES.map((n) => `${n} ${round}`).find((n) => !names.has(n));  const color = COLORS.find((c) => !colors.has(c)) ?? COLORS[here.length % COLORS.length];  return { id, name, color };}// The messages for a join: the newcomer learns who it is and who is here, and everyone else// gets the new list.export function joinMessages(here: readonly Editor[], editor: Editor): { you: ServerMessage; others: ServerMessage } {  const all = [...here, editor];  return { you: { type: "presence", here: all, you: editor }, others: { type: "presence", here: all } };}export function presence(here: readonly Editor[]): ServerMessage {  return { type: "presence", here: [...here] };}// Reads an editor back from a socket attachment, which survives hibernation as structured// clone data. Anything else (a socket accepted before presence existed) is skipped.export function asEditor(v: unknown): Editor | null {  if (typeof v !== "object" || v === null) return null;  const e = v as Record<string, unknown>;  return typeof e.id === "string" && typeof e.name === "string" && typeof e.color === "string" ? { id: e.id, name: e.name, color: e.color } : null;}