import isOnline from 'is-online'
import { Readable } from 'streamx'

import { action, CONNECTIVITY } from '../state.mjs'

export class ConnectivityCheck extends Readable {
  constructor (opts = {}) {
    super()
    this.opts = opts
    this.retryInterval = opts.retryInterval || 2000
    this._lastState = { internet: false }
    this._action(this._lastState)
    this._update()
  }

  async _update () {
    let nextState
    try {
      const hasInternet = await isOnline(this.opts)
      nextState = { internet: hasInternet }
    } catch (err) {
      nextState = { internet: hasInternet }
    } finally {
      this._timeout = setTimeout(() => this._update(), this.retryInterval)
    }
    nextState.changed = nextState.internet !== this._lastState.internet
    this._action(nextState)
    this._lastState = nextState
  }

  _destroy () {
    if (this._timeout) clearTimeout(this._timeout)
  }

  _action (data) {
    if (this.destroyed) return
    this.push(action(CONNECTIVITY, data))
  }
}