Made of little things.

/**
 * Who plays: the Nappelin account the host has signed in, as the game sees it.
 *
 * The web build logs in by reading two inputs in #PowderSessionInfo when it
 * starts (upstream src/client/AuthUserEmscripten.cpp). Filling them from the
 * host's identity means a signed-in player is signed in in the game too, with
 * no password: the key never leaves the host, and every save, vote and
 * comment is signed there.
 */
import * as host from './napplet.js';
import { stableId, usernameFor } from './server/names.js';

export async function currentSession() {
  const pubkey = await host.publicKey();
  if (!pubkey) return null;
  const profile = await host.profile();
  return { pubkey, profile, username: usernameFor(pubkey, profile), userId: stableId(pubkey) };
}

export function writeSessionInfo(session) {
  document.getElementById('PowderSessionInfo')?.remove();
  const form = document.createElement('form');
  form.id = 'PowderSessionInfo';
  form.hidden = true;
  for (const [name, value] of [['Username', session.username], ['SessionKey', 'nappelin']]) {
    const input = document.createElement('input');
    input.type = 'hidden';
    input.name = name;
    input.value = value;
    form.append(input);
  }
  document.body.append(form);
}