const { spawnSync } = require('child_process')
const fs = require('fs')

const getPlaylist = () => {
  const { stderr, stdout } = spawnSync('mpc', ['playlist'])
  return { error: stderr.toString(), playlist: stdout.toString() }
}

const getCurrentTrack = () => {
  const { stderr, stdout } = spawnSync('mpc', ['current'])
  return { error: stderr.toString(), track: stdout.toString() }
}

const skipTrack = () => {
  const { track } = getCurrentTrack()
  const { stderr } = spawnSync('mpc', ['next'])
  return { error: stderr.toString(), skip: track }
}

const insertTrack = spotifyURI => {
  console.log('inserting track:', JSON.stringify(spotifyURI))
  const { stderr, stdout } = spawnSync('mpc', ['insert', spotifyURI])
  console.log(stderr.toString(), stdout.toString())
  return { error: stderr.toString(), insert: stdout.toString() }
}

const insertTrackAsync = spotifyURI => {
  console.log('inserting track:', spotifyURI)
  const promise = new Promise((resolve, reject) => {
    const { stdout, error } = spawnSync('mpc', ['insert', spotifyURI])
    if (error) reject(error.message)
    resolve({ track: stdout.toString() })
  })
  return promise
}

const reset = event => {
  clearAllPlaylists(event)
  addAllPlaylists(event)
}

const clearAllPlaylists = event => {
  const { error } = spawnSync('mpc', ['clear'])
  if (error) return handleError(error, event)
}

const addAllPlaylists = async event => {
  try {
    const files = fs.readdirSync('./playlists')
    const tracks = readPlaylists(files)
    await Promise.all(
      tracks.map(t => insertTrackAsync(t.split(' # ')[0]))
    ).then(() => {
      shuffleAllPlaylists()
      play()
    })
  } catch (e) {
    return handleError(e, event)
  }
}

const readPlaylists = files =>
  files
    .map(f => fs.readFileSync('./playlists/' + f, 'utf-8').split('\n'))
    .reduce((a, b) => a.concat(b))

const handleError = (err, event) => {
  console.log(err)
  return event.reply('Something went wrong.')
}

const shuffleAllPlaylists = event => {
  const { error } = spawnSync('mpc', ['shuffle'])
  if (error) return handleError(error, event)
}

const play = event => {
  const { error } = spawnSync('mpc', ['play'])
  if (error) return handleError(error, event)
}

module.exports = {
  getPlaylist,
  getCurrentTrack,
  skipTrack,
  insertTrack,
  reset,
}