cthuloid / android / lib / ipc-discovery.js

// Unit discovery fed by the app shell over IPC. On Android the shell's Kotlin
// lamp finder (NsdManager, browsing _cthuloid._tcp) does the mDNS work and sends
//   { t: 'unit-up', name, host, addr, port, proto }
//   { t: 'unit-down', name }
//   { t: 'discovery', available, reason }
// which this turns into the same events avahi produces on a desktop
// (webui/lib/discovery.js), so the rig cannot tell them apart.
import EventEmitter from 'bare-events'

export class IpcDiscovery extends EventEmitter {
  constructor () {
    super()
    this.available = true
    this.reason = ''
  }

  start () {}
  stop () {}

  // Returns true if the message was a discovery message.
  handle (m) {
    if (!m || typeof m !== 'object') return false
    if (m.t === 'unit-up') {
      const port = Number(m.port)
      if (!m.name || !m.addr || !Number.isInteger(port)) return true
      this.emit('up', {
        name: String(m.name),
        host: String(m.host || m.name + '.local'),
        addr: String(m.addr),
        port,
        proto: Number(m.proto) || 0
      })
      return true
    }
    if (m.t === 'unit-down') {
      if (m.name) this.emit('down', { name: String(m.name) })
      return true
    }
    if (m.t === 'discovery') {
      const was = this.available
      this.available = !!m.available
      this.reason = this.available ? '' : String(m.reason || 'lamp discovery is not running')
      if (was !== this.available) this.emit(this.available ? 'available' : 'unavailable', this.reason)
      return true
    }
    return false
  }
}