const ytdl = require('ytdl-core'),
  fs = require('fs'),
  path = require('path'),
  express = require('express'),
  bodyParser = require('body-parser'),
  cp = require("child_process"),
  ffmpeg = require('ffmpeg-static'),
  multer = require('multer')


const PORT = process.env.PORT || 8080
const app = express()

var formats = {
  "matroska": "mkv"
}

if (fs.existsSync(path.join(__dirname, 'uploads'))) {
  fs.rmSync(path.join(__dirname, 'uploads'), { recursive: true })
}

var uploads = multer({ dest: 'uploads/' })

const characters = "abcdefghijklmnopqrstuvwxyz!@$%^*()[]_-=+ "

process.on('uncaughtException', (err, origin) => {
  fs.writeSync(
    process.stderr.fd,
    `Caught exception: ${err}\n` +
    `Exception origin: ${origin}`,
  );
});

app.use(bodyParser.urlencoded({ extended: false }))

app.post("/convert", uploads.single("files"), (req, res) => {
  var file = req.file
  var format = req.body.format || 'mp4'

  const ffmpegProcess = cp.spawn(ffmpeg, [
    '-i', file.path,
    '-f', format,
    '-loglevel', 'error',
    '-movflags', 'frag_keyframe+empty_moov',
    '-vcodec', 'copy' ,
    '-acodec', 'copy',
    '-'
  ], {
    stdio: [
      'pipe', 'pipe', 'pipe', 'pipe', 'pipe',
    ],
  })

  res.setHeader('Content-Disposition', `attachment; filename="${file.originalname.substring(0, file.originalname.lastIndexOf('.'))}.${formats[format] || format}"`);
  ffmpegProcess.stdio[1].pipe(res)

  .on("close", () => {
    fs.rmSync(file.path)
  })
})

app.get("/download", async (req, res) => {
  const url = req.query.url
  const format = req.query.format || 'mp4'
  const quality = req.query.quality || 'highest'
  const defin = req.query.definition || 'hd'
  const preset = 'medium'

  res.setHeader("X-Accel-Buffering", "no")

  if (!ytdl.validateURL(url)) {
    res.header("Content-Type", "text/html")
    res.write(`<link rel="stylesheet" href="/style.css">`)
    res.write(`<p>Invalid URL! Check the url for any errors! <br>URL: ${url}</p>`)
    return
  }

  var vidinfo = await ytdl.getBasicInfo(url)

  const ogname = vidinfo.videoDetails.title
  var filename = ""

  for (let index = 0; index < ogname.length; index++) {
    const letter = ogname[index];
    if ((characters + characters.toUpperCase()).includes(letter)) {
      filename += letter
    }
  }

  if ("mp3 ogg wav".includes(format)) {
    var audio = ytdl(url, { filter: 'audioonly', quality: quality })

    const ffmpegProcess = cp.spawn(ffmpeg, [
      '-i', `pipe:3`,
      '-preset', preset,
      '-f', format,
      '-loglevel', 'error',
      '-'
    ], {
      stdio: [
        'pipe', 'pipe', 'pipe', 'pipe', 'pipe',
      ],
    })

    audio.pipe(ffmpegProcess.stdio[3])

    res.setHeader('Content-Disposition', `attachment; filename="${filename}.${formats[format] || format}"`);

    ffmpegProcess.stdio[1].pipe(res)

  } else if (defin == "hd") {
    var video = ytdl(url, { filter: 'videoonly', quality: quality })
    var audio = ytdl(url, { filter: 'audioonly', highWaterMark: 1 << 25 })

    const ffmpegProcess = cp.spawn(ffmpeg, [
      '-i', `pipe:3`,
      '-i', `pipe:4`,
      '-map', '0:v',
      '-map', '1:a',
      '-c:v', 'copy',
      '-c:a', 'libmp3lame',
      '-crf', '27',
      '-preset', preset,
      '-movflags', 'frag_keyframe+empty_moov',
      '-f', format,
      '-loglevel', 'error',
      '-'
    ], {
      stdio: [
        'pipe', 'pipe', 'pipe', 'pipe', 'pipe',
      ],
    })

    video.pipe(ffmpegProcess.stdio[3])
    audio.pipe(ffmpegProcess.stdio[4])

    res.setHeader('Content-Disposition', `attachment; filename="${filename}.${formats[format] || format}"`);
    ffmpegProcess.stdio[1].pipe(res)

  } else {
    var video = ytdl(url, { filter: 'videoandaudio', quality: quality })

    const ffmpegProcess = cp.spawn(ffmpeg, [
      '-i', `pipe:3`,
      '-preset', preset,
      '-f', format,
      '-loglevel', 'error',
      '-'
    ], {
      stdio: [
        'pipe', 'pipe', 'pipe', 'pipe', 'pipe',
      ],
    })

    video.pipe(ffmpegProcess.stdio[3])

    res.setHeader('Content-Disposition', `attachment; filename="${filename}.${formats[format] || format}"`);
    // res.setHeader('Content-Length', fs.readFileSync(dest).length)

    ffmpegProcess.stdio[1].pipe(res)
  }

})

app.use(express.static(path.join(__dirname, 'static')))

app.listen(PORT, function () {
  console.log("Hosted on port " + PORT)
})