btrtracks/src/lastfm.js

import path from 'path'
import as from './common/async'
import dl from './common/download'
import crypto from 'crypto'

const values = require(path.join(process.cwd(), 'values.json'))

let externalTracks = {}

function createHash (data) {
  return crypto
    .createHash('sha1')
    .update(data.artist + data.name)
    .digest('hex')
    .substr(0, 8)
}

async function getTrackMetaReal (id) {
  if (!id || !externalTracks[id]) return null
  let trdata = externalTracks[id]
  if (trdata.file) return Object.assign({}, trdata)

  let trsrch = 'ytsearch1:' + trdata.artist + ' - ' + trdata.title
  let dldata = await dl.getVideoInfo(trsrch)

  externalTracks[id] = {
    id: trdata.id,
    title: trdata.title,
    artist: trdata.artist,
    file: dldata.url,
    duration: dldata.duration,
    external: true
  }

  return Object.assign({}, externalTracks[id])
}

async function search (track, limit = 30) {
  if (!values.lastfm) return []

  let data
  try {
    data = await as.GET(`http://ws.audioscrobbler.com/2.0/?method=track.search&track=${track}&api_key=${values.lastfm}&format=json&limit=${limit}`)
    data = JSON.parse(data)

    if (!data.results || !data.results.trackmatches || !data.results.trackmatches.track) {
      throw new Error('No results')
    }
  } catch (e) {
    return []
  }

  let final = []
  for (let i in data.results.trackmatches.track) {
    let res = data.results.trackmatches.track[i]
    let clean = {
      id: createHash(res),
      artist: res.artist,
      title: res.name,
      external: true
    }

    if (externalTracks[clean.id]) {
      // Copy object
      clean = Object.assign({}, externalTracks[clean.id])
    } else {
      // Save in cache
      externalTracks[clean.id] = clean
    }

    final.push(clean)
  }

  return final
}

export default {search, getTrackMetaReal}