#!/usr/bin/env node
'use strict'

const spawn = require('child_process').spawn
const fs = require('fs')

const readline = require('readline')

const rl = readline.createInterface({
 input: process.stdin,
 output: process.stdout
})

function download (arg, handleCb) {
  let yt = spawn('youtube-dl', ['--no-playlist', '--playlist-end', 1, '-j', '-f', 'bestaudio/best', arg])

  let output = ''

  yt.stdout.on('data', function (chunk) {
    output += chunk.toString('utf8')
  })
  yt.on('close', function () {
    let data = JSON.parse(output)
    delete data.formats
    fetchVideo(data, handleCb)
  })
}

function fetchVideo (data, cb) {
  console.log('audio codec:', data.acodec)
  if (data.acodec !== 'mp3' || data.vcodec !== 'none') {
    let tempName = __dirname + '/tmp.yt.' + data.id + '.mp3'
    let ffmpeg = spawn('ffmpeg', ['-hide_banner', '-i', data.url, '-codec:a', 'libmp3lame', '-q:a', 2, '-joint_stereo', 1, '-y', tempName])

    ffmpeg.stdout.pipe(process.stderr)
    ffmpeg.stderr.pipe(process.stderr)
    data.filename = tempName
    console.log('Downloading ' + data.title + '...')

    ffmpeg.on('close', function () {
      outputVideo(data, cb)
    })
  } else {
    console.log('Invalid format returned.')
    cb(null)
  }
}

function outputVideo (video, cb) {
  cb({
    title: video.title,
    artist: video.uploader,
    url: video.webpage_url,
    art: video.thumbnail,
    source: video.filename
  })
}

function parseTitle(data) {
  let tt = data.title

  // Remove []'s from the beginning
  tt = tt.replace(/^\[\w+\]\s?/i, '')

  // Remove "Official Video/Audio" tag
  tt = tt.replace(/\s?(?:[\(\)\[\]])?Official\s?[\w]+(?:[\(\)\[\]])?/i, '')

  // Remove "Audio" tag
  tt = tt.replace(/\s?(?:[\(\)\[\]])Audio?(?:[\(\)\[\]])/i, '')

  // Remove "lyrics" tag
  tt = tt.replace(/\s?(?:[\(\)\[\]])?lyrics?\s?(?:[\w]+)?(?:[\(\)\[\]])?\s?/i, '')

  // Artist / Title split
  let at = tt.split(' - ', 2)
  let artist
  let title

  if (at.length > 1) {
    artist = at[0]
    title = tt.substring(artist.length + 3)
  } else {
    artist = data.artist
    title = tt
  }

  data.title = title
  data.artist = artist

  return data
}

download(process.argv[2], function (s) {
  let clean = parseTitle(s)
  let filename = clean.artist + ' - ' + clean.title + '.mp3'

  console.log('Cleaning up..')
  console.log('Original Title: ' + s.title + '\n')
  console.log('Determined Title: ' + clean.title)
  console.log('Determined Artist: ' + clean.artist)
  console.log('Determined File Name: ' + filename)

  rl.question(`Title [${clean.title}] ? `, (answer) => {
    if (answer && answer.trim() !== '') {
      clean.title = answer
    }

    rl.question(`Artist [${clean.artist}] ? `, (answer) => {
      if (answer && answer.trim() !== '') {
        clean.artist = answer
      }

      rl.question(`File [${filename}] ? `, (answer) => {
        if (answer && answer.trim() !== '') {
          filename = answer
        }

        let fn = __dirname + '/' + filename
        fs.rename(s.source, fn, function (err) {
          if (err) {
            console.error(err)
            return rl.close()
          }

          let id3 = spawn('id3', ['-a', clean.artist, '-t', clean.title, fn])
          id3.on('close', () => {
            console.log('Saved as ' + fn)
            rl.close()
          })
        })
      })
    })
  })
})