DM echo bot

import { Client } from '@cloak-software/bot-sdk';

// Optional. Set it to have the bot open a DM with you at startup.
const target = process.env.DM_TARGET_USER_ID;

const client = new Client({
  token: process.env.CLOAK_TOKEN!,
  // Persists the identity, the DM keys, and the peer-to-dm-id map. Without it
  // every restart re-runs the key exchange, and (far worse) a regenerated
  // identity can never be republished: publication is write-once server-side.
  keystorePath: './dm-bot.cloak-keystore.json',
  requiredPermissions: ['message_send'],
});

client.on('ready', async () => {
  console.log(`Logged in as bot ${client.user?.id}`);
  console.log('DM this bot from a Cloak client. You must own it, or share a server with it.');
  if (!target) {
    console.log('Set DM_TARGET_USER_ID to also have it open a DM with you at startup.');
    return;
  }
  try {
    // Lazily runs create plus key exchange, then the send. There is no
    // separate "open a DM" step to call.
    await client.sendDM(target, 'hello from dm-bot, reply and I will echo you');
    console.log(`sent the opening DM to ${target}`);
  } catch (e) {
    // The interesting failure: not the owner, and no shared server.
    console.error('sendDM failed:', (e as Error).message);
  }
});

client.on('messageCreate', async (msg) => {
  if (msg.authorId === client.user?.id) return; // ignore our own messages
  if (!msg.isDM) return; // server traffic is not this bot's business

  console.log(`DM from ${msg.authorName} (${msg.authorId}) in dm ${msg.dmId}: ${msg.content}`);
  // serverId is null here. Never pass it to a server-scoped call.
  console.log(`  serverId=${String(msg.serverId)} channelId=${msg.channelId}`);

  try {
    // reply() routes back into the DM and renders the quote header. No create
    // and no key exchange: the inbound message proved both already exist.
    await msg.reply(`echo: ${msg.content || '(could not decrypt, key still in flight?)'}`);
  } catch (e) {
    console.error('reply failed:', (e as Error).message);
  }
});

// The DM key path reports through the same `error` event as every other
// internal failure. This changes no control flow. It makes a stalled key
// exchange visible instead of silent.
client.on('error', (e) => console.error('[client error]', e.source, e.context, e.message));

client.on('sendRejected', (r) => {
  // A DM deny carries no routing, so serverId is null and channelId is a hint.
  console.error(`send rejected (${r.code}): ${r.message}`);
});

client.on('disconnect', (e) => console.error('disconnected', e));

await client.login();