import { RedisClient } from '../redis/RedisClient'
import ip from 'internal-ip'

const signals: NodeJS.Signals[] = ['SIGINT', 'SIGTERM', 'SIGUSR2']

const NODES_SET = 'poker:infosvr'
const discovery_channel = 'poker:infosvr:discovery'
const isProd = process.env.NODE_ENV === 'production'

export function registerGracefulShutdown(callback: (err?: Error) => void) {
  /**
   * Gracefully shutdown on uncaught errors
   */
  process.on('uncaughtException', (err) => {
    console.error(err)
    callback(err)
  })

  signals.forEach((signal) => {
    process.once(signal, () => callback())
  })
}

async function getNodeAddress(port: number) {
  const host = process.env.SELF_HOSTNAME || await ip.v4()
  return `${ host }:${ port }`
}

export async function registService(port: number) {
  if (!isProd) {
    return
  }
  const address = await getNodeAddress(port)
  const client = new RedisClient()
  await client.sadd(NODES_SET, address)
  await client.publish(discovery_channel, `add,${address}`)
}

export async function unRegistService(port: number) {
  if (!isProd) {
    return
  }
  const address = await getNodeAddress(port)
  const client = new RedisClient()
  await client.srem(NODES_SET, address)
  await client.publish(discovery_channel, `remove,${address}`)
}