btrtracks/src/lastfm.js

import path from 'path'
import rp from 'request-promise-native'
import crypto from 'crypto'
import { dbPromise } from './database'
import { addListExternal } from './external'
import { parseStringPromise } from 'xml2js'

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

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

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

  let data
  try {
    data = await rp(`http://ws.audioscrobbler.com/2.0/?method=track.search&track=${track}&api_key=${values.lastfm.key}&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 []
  }

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

    clean = addListExternal(clean.id, clean)

    final.push(clean)
  }

  return final
}

// Authentication

function getAPISig (params) {
  let allStrings = []
  const qs = {}
  params.api_key = values.lastfm.key
  for (const key in params) {
    const val = params[key]
    if (val == null || val === '') continue
    allStrings.push(key + val)
    qs[key] = val
  }
  allStrings = allStrings.sort()
  allStrings.push(values.lastfm.secret)
  qs.api_sig = crypto.createHash('md5').update(allStrings.join('')).digest('hex')
  return qs
}

function getAuthURL () {
  return 'http://www.last.fm/api/auth/?api_key=' + values.lastfm.key + '&cb=' + values.lastfm.redirectUri
}

async function getSession (token) {
  const sessSig = getAPISig({ token, method: 'auth.getSession' })
  const res = await rp('http://ws.audioscrobbler.com/2.0/', { qs: sessSig })
  const rep = await parseStringPromise(res)
  const name = rep.lfm.session[0].name[0]
  const key = rep.lfm.session[0].key[0]
  return { name, key }
}

async function storeSession (userId, session) {
  if (!session.name || !session.key) throw new Error('Invalid session parameter.')
  const db = await dbPromise
  const existing = await db.get('SELECT * FROM LastFM WHERE userId = ?', userId)
  if (existing) {
    await db.run('UPDATE LastFM SET name = ?, key = ? WHERE userId = ?', session.name, session.key, userId)
  } else {
    await db.run('INSERT INTO LastFM (userId,name,key,created) VALUES (?,?,?,?)', userId, session.name, session.key, new Date())
  }
  return true
}

async function disregardSession (userId) {
  const db = await dbPromise
  return db.run('DELETE FROM LastFM WHERE userId = ?', userId)
}

async function getSessionForUser (userId) {
  const db = await dbPromise
  return db.get('SELECT * FROM LastFM WHERE userId = ?', userId)
}

async function scrobbleTrack (userId, trackData) {
  const sess = await getSessionForUser(userId)
  if (!sess) throw new Error('User does not have a LastFM session.')
  const scrobbleSig = getAPISig({
    sk: sess.key,
    method: 'track.scrobble',
    artist: trackData.artist || 'Unknown',
    title: trackData.title,
    album: trackData.album,
    duration: trackData.duration,
    mbid: trackData.mbid,
    timestamp: Math.floor(Date.now() / 1000)
  })
  await rp.post('http://ws.audioscrobbler.com/2.0/', { form: scrobbleSig })
  return true
}

export {
  search,
  getAPISig,
  getAuthURL,
  getSession,
  getSessionForUser,
  storeSession,
  disregardSession,
  scrobbleTrack
}