btrtracks/src/common/download.js

import {spawn} from 'child_process'
import ffmpeg from 'fluent-ffmpeg'

import path from 'path'
import asn from './async'

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
}

function getVideoInfo (arg) {
  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')
  })

  return new Promise((resolve, reject) => {
    yt.on('close', function () {
      let data = JSON.parse(output)
      delete data.formats
      resolve(data)
    })
  })
}

function fetchVideo (data) {
  return new Promise((resolve, reject) => {
    let tempName = path.join(process.cwd(), `/tmp.yt.${data.id}.mp3`)
    ffmpeg(data.url)
      .audioCodec('libmp3lame')
      .format('mp3')
      .on('error', reject)
      .on('end', function () {
        resolve({
          title: data.title,
          artist: data.uploader,
          url: data.webpage_url,
          art: data.thumbnail,
          source: tempName
        })
      })
      .output(tempName)
      .run()
  })
}

async function getInfos (file) {
  let formatData = await asn.promiseExec(`ffprobe -i "${file}" -show_entries format -v quiet -of json`)

  let parsed = JSON.parse(formatData.stdout)
  if (!parsed || !parsed.format || !parsed.format.duration) throw new Error('Failed to parse metadata!')
  parsed = parsed.format

  let data = {
    file,
    duration: parseFloat(parsed.duration)
  }

  if (Math.floor(data.duration) === 0) throw new Error('Invalid file type!')

  if (parsed.tags) {
    for (let k in parsed.tags) {
      let tagtype = k.toLowerCase()
      let value = parsed.tags[k]

      if (tagtype === 'date') tagtype = 'year'
      if (tagtype === 'track' || tagtype === 'year') {
        if (value.indexOf('/') !== -1) {
          value = value.split('/')[0]
        }

        value = parseInt(value)
      }

      data[tagtype] = value
    }
  }

  if (!data.title) {
    let parsed = path.parse(file)
    data.title = parsed.name
  }

  return data
}

export default {parseTitle, getVideoInfo, fetchVideo, getInfos}