#!/usr/bin/env node
/* pruss.it */

const https = require('https')
const readline = require("readline")
const spawn = require('child_process').spawn

let results = []

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

const p = {
  log: m => console.log(m),
  cls: () => console.clear(),
  inf: m => console.log(`\x1b[32m${m}\x1b[0m`),
  err: e => console.error(`\x1b[31m${e}\x1b[0m`),
  prt: () => prompt(),
  res: () => showResults()
}

const joinRuns = t => t
  ? t.runs
    ? t.runs.map(r => r.text).join('').split(/\r\n|\r|\n/).slice(0,14).join('\n')
    : t.simpleText
  : '-'

const convertViews = (v) => {
  const t = v ? v.split(' ')[0].split('.') : '-'
  switch(t.length) {
    case 2: return t[0] + 'K'
    case 3: return t[0] + 'M'
    case 4: return t[0] + 'B'
    default: return t
  }
}

const findNested = (obj, key) => {
  let r
  for (let k in obj) {
    if (obj.hasOwnProperty(k)) {
      if (k === key) return obj[key]
      else if (typeof obj[k] === "object") {
        r = findNested(obj[k], key)
        if (typeof r !== "undefined") return r
      }
    }
  }
}

const findAllNested = (o, p) => {
  var r = []
  const f = (n, r) => {
    if(n.hasOwnProperty(p)) r.push(n[p])
    for(var i=0; i<Object.keys(n).length; i++){
      if(typeof n[Object.keys(n)[i]] == "object"){
        f(n[Object.keys(n)[i]], r)
      }
    }
    return r
  }
  return f(o, r)
}

const showResults = () => {
  results.forEach((r, i) => {
    p.log(`\x1b[33m${i+1}. \x1b[36m${r.title} \x1b[32m[${r.length}] \x1b[35m${r.channel} \x1b[31m${r.views}\x1b[0m`)
  })
  p.log(' ')
}

const parseVideos = o => o.map(v => ({
  id: v.videoId,
  title: joinRuns(v.title),
  length: v?.lengthText?.simpleText,
  views: convertViews(v?.viewCountText?.simpleText),
  channel: joinRuns(v?.shortBylineText)
}))

const handleResObj = (x) => {
  const n = (findAllNested(JSON.parse(x[0])['contents'], 'videoRenderer'))
  results = parseVideos(n)
  p.cls(); p.res(); p.prt()
}

const objFromRes = (r, c) => {
  const x = r.match(/(?<=ytInitialData = )(.*?)(?=;<\/script>)/gm)
  if (x) c(x)
}

const getResponse = (u, c) => https.get(u, res => {
  var r = ''
  res.on('data', d => { r += d })
  res.on('end', () => { objFromRes(r, c) })
  res.on('error', e => { p.err(e) })
})

const isSongRange = q => q.match(/^[0-9]+-[0-9]+$/)

const isSongName = q => q.match(/.{3,}/)

const isRelated = q => q.match(/^r[0-9]+$/) && parseInt(q.replace('r','')) <= results.length

const isSongNumber = q => q.match(/^[0-9]+$/) && parseInt(q) <= results.length

const showPlaying = n => {
  getResponse(('https://www.youtube.com/watch?v='+results[n].id), x => {
    p.log('\x1b[32mDescription:\n------------\x1b[36m')
    p.log(joinRuns(findNested(JSON.parse(x)['contents'], 'description')), '\x1b[0m')
    p.log(' ')
  })
  p.log(`\n\x1b[32mCurrently playing:\n------------------\n\x1b[32mTitle: \x1b[36m${results[n].title}\n\x1b[32mChannel: \x1b[36m${results[n].channel}\n\x1b[32mLength: \x1b[36m${results[n].length}\n\x1b[32mViews: \x1b[36m${results[n].views}\x1b[0m\n`)
}

const showPlaylist = (r, n) => p.log(r.map(x=>`${x===n?'\x1b[33m':'\x1b[36m'}${x}. ${results[x-1].title}\x1b[0m`).join('\n'),'\n')

const playNr = (n) => spawn('mpv', ['--no-video', '--msg-level=all=no,statusline=status', `https://www.youtube.com/watch?v=${results[parseInt(n)].id}`], { stdio: 'inherit' })

const playNext = (r, n) => {
  p.cls()
  p.inf('Playlist:\n---------')
  showPlaylist(r, n)
  showPlaying(n-1)
  const player = playNr(n-1)
  player.on('close', () => {
    if (n < r[r.length-1]){
      playNext(r, n+1)
    } else {
      p.cls(); p.res(); p.prt()
    }
  })
}

const handleSongRange = q => {
  if (results.length > 0) {
    const [a,b] = q.split('-').map(n=>parseInt(n))
    if (a<b){
      const range = [...Array(b-a+1).keys()].map(n=>n+a)
      playNext(range, range[0])
    } else {
      p.cls(); p.res(); p.err('invalid range, try again'); p.prt()
    }
  } else {
    p.cls(); p.err('first search for the videos'); p.prt()
  }
};

const handleRelated = q => getResponse(('https://www.youtube.com/watch?v='+results[parseInt(q.substring(1)) - 1].id), x => {
  results = parseVideos(findAllNested(JSON.parse(x)['contents'], 'compactVideoRenderer'))
  p.cls(); p.res(); p.prt()
})

const handleSongName = q => getResponse(('https://www.youtube.com/results?search_query='+q.replaceAll(' ', '+')), handleResObj)

const handleSongNumber = q => {
  const nr = parseInt(q) - 1
  p.cls(); showPlaying(nr)
  const player = playNr(nr)
  player.on('close', () => { p.cls(); p.res(); p.prt() })
}

const handleHelp = () => {
  p.cls()
  p.log('\x1b[36mYT Audio Player (HELP)\n----------------------\n1. Type song name and press [ENTER] to search it in YT\n2. Type result number and press [ENTER] to play the song\n3. Type a range of songs (ex. [2-5]) to play them in a row\n4. Type [r(nr)] (ex. [r2]) to find songs related to chosen result\n5. Type [h] and press [ENTER] to see this help page\n6. Type [q] and press [ENTER] to quit YT audio player\x1b[0m\n')
  p.prt()
}

const handleQuit = () => {
  rl.close(); p.cls(); p.inf('See you!\n\n'); return 0
}

const handleWrongInput = () => {
  p.cls(); p.res(); p.err('wrong input\n'); p.prt()
}

const handlePrompt = q => {
  rl.pause()

  if (isSongRange(q)) {
    handleSongRange(q)
  } else if (isRelated(q)) {
    handleRelated(q)
  } else if (isSongName(q)) {
    handleSongName(q)
  } else if (isSongNumber(q)) {
    handleSongNumber(q)
  } else if (q === 'h') {
    handleHelp()
  } else if (q === 'q') {
    handleQuit()
  } else {
    handleWrongInput()
  }
}

const prompt = () => {
  rl.resume()
  rl.question("\x1b[32mYT Audio Player ([h]elp, [q]uit): \x1b[0m", k => { handlePrompt(k) })
}

p.cls(); p.prt()