Webhook embed bot

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

// The recommended path. A human creates the webhook in the Cloak app under
// room settings > Webhooks, and you put its url in an env var. The bot then
// needs no permissions at all to post through it.
//
// The url embeds the webhook's token secret and the server stores only its
// hash: it is shown exactly once and cannot be re-fetched. Never commit it,
// never log it. The SDK keeps it out of every error it raises.
const webhookUrl = process.env.CLOAK_WEBHOOK_URL;

const client = new Client({
  token: process.env.CLOAK_TOKEN!,
  // Not optional. Identity publication is write-once server-side, so a bot
  // with no keystore works on its first run and can never log in again.
  keystorePath: './embed-bot.cloak-keystore.json',
  // manage_server is needed only by the !mint and !hooks paths below. Drop it
  // from this list if you only ever post to a human-created url.
  requiredPermissions: ['message_send', 'manage_server'],
  webhookName: 'Embed Example', // the name a minted webhook posts under
});

function buildEmbed(text: string) {
  return {
    title: 'Example embed',
    description: text,
    // Either a CSS color string or a Discord decimal int. Both render.
    color: '#22c55e',
    url: 'https://cloak.chat',
    fields: [
      { name: 'Lane', value: 'webhook (plaintext)', inline: true },
      { name: 'Encrypted', value: 'no', inline: true },
    ],
    footer: { text: 'posted by embed-bot' },
    timestamp: new Date().toISOString(),
    // image / thumbnail / video urls, and every *_icon_url, are dropped
    // silently unless the backend has its image proxy configured. The POST
    // still returns success. Text and links always survive.
    // image: { url: 'https://example.com/banner.png' },
  };
}

client.on('ready', () => {
  console.log(`Logged in as bot ${client.user?.id}`);
  console.log(webhookUrl ? 'CLOAK_WEBHOOK_URL is set, !embed will work' : 'no CLOAK_WEBHOOK_URL, !embed disabled');
});

client.on('messageCreate', async (msg) => {
  if (msg.authorId === client.user?.id) return; // ignore our own messages
  // Webhooks are server-scoped, and a direct message has a null serverId.
  if (msg.isDM || !msg.serverId) return;

  const [cmd, ...rest] = msg.content.trim().split(/\s+/);
  const text = rest.join(' ') || 'hello from the webhook lane';

  try {
    if (cmd === '!embed') {
      if (!webhookUrl) return void (await msg.reply('set CLOAK_WEBHOOK_URL first'));
      await client.webhooks.post(webhookUrl, {
        unencrypted: true, // required: this message is NOT end-to-end encrypted
        username: 'Embed Example', // per-post display name, 1 to 80 chars
        embeds: [buildEmbed(text)],
      });
    } else if (cmd === '!mint') {
      // Mints, or reuses, a webhook for this channel. Needs manage_server.
      // Reuse only ever adopts a webhook this bot created.
      await client.sendEmbed(msg.serverId, msg.channelId, {
        unencrypted: true,
        embeds: [buildEmbed(text)],
      });
    } else if (cmd === '!hooks') {
      const hooks = await client.guild(msg.serverId).webhooks.list();
      await msg.reply(
        hooks.length
          ? hooks.map((h) => `${h.name} (${h.id}) in ${h.channelId}`).join('\n')
          : 'no webhooks on this server',
      );
    }
  } catch (e) {
    // CloakWebhookError is the delivery failure (the HTTPS POST). A CRUD
    // denial arrives as CloakActionError with .permission set instead.
    // Neither ever carries the delivery url: it is a bearer credential.
    if (e instanceof CloakWebhookError) {
      console.error(`webhook post failed: ${e.status} ${e.detail}`);
    } else {
      console.error(`${cmd} failed`, e);
    }
    await msg.reply(`${cmd} failed: ${(e as Error).message}`).catch(() => undefined);
  }
});

client.on('error', (e) => console.error('sdk error', e.source, e.message));
client.on('disconnect', (e) => console.warn('disconnected', e));

client.login().catch((e) => {
  console.error('login failed', e);
  process.exit(1);
});