import 'dotenv/config'
import mqtt from 'mqtt'
import { v4 as uuidv4 } from 'uuid'

const MQTT_URL = process.env.MQTT_URL
if (!MQTT_URL) throw new Error('Missing MQTT_URL')

const pattern = process.env.ACK_TOPIC_PATTERN || 'device/+/ack'
const target = process.env.SIM_ACK_TARGET // e.g. userId or deviceId to fill the '+'
const correlationId = process.env.SIM_CORRELATION_ID || uuidv4()

const topic = (() => {
  const parts = pattern.split('/')
  const tParts = []
  let used = false
  for (const p of parts) {
    if (p === '+') { tParts.push(target || 'test'); used = true } else tParts.push(p)
  }
  if (pattern.includes('+') && !used) throw new Error('Pattern contains + but could not fill it')
  return tParts.join('/')
})()

const payload = JSON.stringify({ correlation_id: correlationId, ok: true, t: Date.now() })

console.log('Publishing ACK', { topic, correlationId })
const client = mqtt.connect(MQTT_URL, { clientId: `ack-sim-${Math.random().toString(16).slice(2)}` })
client.on('connect', () => {
  client.publish(topic, payload, { qos: 1 }, (err) => {
    if (err) console.error('publish error', err)
    else console.log('ACK published')
    setTimeout(() => client.end(true, () => process.exit(err ? 1 : 0)), 200)
  })
})
client.on('error', (e) => { console.error('mqtt error', e); process.exit(2) })