Noise Sensors

import { createServer } from 'node:http'
import { DatabaseSync } from 'node:sqlite'
import { SeamWebhook } from 'seam'

const secret = process.env.SEAM_WEBHOOK_SECRET
const workspaceId = process.env.SEAM_WORKSPACE_ID
if (!secret || !workspaceId) throw new Error('Set the webhook secret and workspace ID.')
const webhook = new SeamWebhook(secret)
const db = new DatabaseSync(process.env.ALERT_DB_PATH || './noise-alerts.sqlite')
db.exec(`
  PRAGMA journal_mode = WAL;
  CREATE TABLE IF NOT EXISTS noise_alerts (
    workspace_id TEXT NOT NULL,
    event_id TEXT NOT NULL,
    device_id TEXT NOT NULL,
    occurred_at TEXT NOT NULL,
    payload TEXT NOT NULL,
    status TEXT NOT NULL DEFAULT 'pending',
    PRIMARY KEY (workspace_id, event_id)
  );
`)
const insert = db.prepare(`
  INSERT INTO noise_alerts (workspace_id, event_id, device_id, occurred_at, payload)
  VALUES (?, ?, ?, ?, ?)
  ON CONFLICT (workspace_id, event_id) DO NOTHING
`)

createServer(async (req, res) => {
  if (req.method !== 'POST' || req.url !== '/webhooks/seam') {
    res.writeHead(404).end()
    return
  }
  let event
  try {
    const chunks = []
    let size = 0
    for await (const chunk of req) {
      size += chunk.length
      if (size > 1024 * 1024) {
        res.writeHead(413).end()
        return
      }
      chunks.push(chunk)
    }
    // Verify the original bytes, before parsing or changing the body.
    event = webhook.verify(Buffer.concat(chunks).toString('utf8'), req.headers)
  } catch {
    console.warn('Rejected webhook verification')
    res.writeHead(400).end()
    return
  }
  if (event.workspace_id !== workspaceId) {
    res.writeHead(403).end()
    return
  }
  if (event.event_type !== 'noise_sensor.noise_threshold_triggered') {
    res.writeHead(204).end()
    return
  }
  if (typeof event.device_id !== 'string' || typeof event.occurred_at !== 'string') {
    res.writeHead(400).end()
    return
  }
  try {
    const result = insert.run(event.workspace_id, event.event_id, event.device_id,
      event.occurred_at, JSON.stringify(event))
    console.log(JSON.stringify({ event_id: event.event_id, queued: result.changes === 1 }))
    // Acknowledge only after the durable insert, including an existing duplicate.
    res.writeHead(204).end()
  } catch {
    console.error('Noise event could not be stored; leave delivery retryable.')
    res.writeHead(500).end()
  }
}).listen(Number(process.env.PORT || 3000), '127.0.0.1')