const readline = require("readline");
const ytdl = require("ytdl-core");
const ffmpeg = require("fluent-ffmpeg");
const id3 = require('node-id3');
const axios = require('axios');
const request = require("request").defaults({ encoding: null });
const chalk = require('chalk');
const cp = require('child_process');
const fs = require('fs');
const path = require('path');
const terminalLink = require('terminal-link');
const hasflag = require('has-flag');
const gradient = require('gradient-string');
const figlet = require('figlet');

/**
 * log function for logging in one shell line.
 * @param {any} something the thing that should be logged.
*/
const log = (something) => {
  readline.clearLine(process.stdout, 0);
  readline.cursorTo(process.stdout, 0);
  process.stdout.write(something);
}
/**
 * convertTime converts a string to a number of seconds.
 * @param {string} timeString like '00:00:46.27'
 */
const convertTime = (timeString) => {
  const timeParts = timeString.split(':');
  let seconds = Number(timeParts[2]);
  seconds = seconds + (Number(timeParts[1]) * 60) + (Number(timeParts[0]) * 60 * 60);
  return seconds;
};

if (process.argv.find(v => v === "help" || v === "-h" || v === "--help")) {
  console.log(gradient.rainbow.multiline(figlet.textSync("ytdownloader", {horizontalLayout: 'fitted'})));
  console.log(chalk.underline("\nUsage:"));
  console.log(`node main.js ${chalk.italic("<YouTube video url> <?Artist name> <?Song name>")}\n`);
  console.log("The arguments starting with <? are optional. If not specified the song won't have id3 tags written to it.");

  process.exit();
}

if (process.argv.length !== 5) {
  console.log(chalk.yellowBright("⚠️　Not getting metadata for this song; expected arguments are not given!"));
}

const ffmpegPath = path.join(__dirname + "/ffmpeg");
if (fs.existsSync(ffmpegPath)) {
  // On linux, you require the command-line version of ffmpeg.
  if (process.platform !== "linux") ffmpeg.setFfmpegPath(ffmpegPath);
} else {
  console.error(chalk.redBright("❌　The FFmpeg executable wasn't found. See " + terminalLink("ffmpeg's website", "https://www.ffmpeg.org") + " for downloads."))
  process.exit(1);
}

log(chalk.yellow("ℹ️　Getting information from YouTube..."));

ytdl.getInfo(process.argv[2], (err, info) => {
  let stream = ytdl(process.argv[2], {
    quality: "highestaudio"
    //filter: 'audioonly',
  });

  const filePath = path.join(__dirname, `/music/${info.title}.mp3`);

  log(chalk.yellow("🏁　Starting download..."));

  ffmpeg(stream)
    .audioBitrate(128)
    .save(filePath)
    .on("progress", p => {
      const progress = convertTime(p.timemark);
      log(
        chalk.blue(
          `⬇️　${Math.floor(
            (progress / Number(info.length_seconds)) * 100
          )}% downloaded. (${p.targetSize}kB)`
        )
      );
    })
    .on('error', err => {
      console.error(chalk.redBright('❌　Found an error: ' + err.message));
      process.exit(1);
    })
    .on("end", () => {
      if (process.argv.length === 5) {
        // Retreiving info from itunes api and writing tags to downloaded file.
      const artist = process.argv[3];
      const song = process.argv[4];

      log(chalk.yellow("🎵　Calling iTunes api..."));

      axios.get(`https://itunes.apple.com/search?term=${artist} ${song}&entity=song`).then(res => {
        request.get(res.data.results[0].artworkUrl100.replace('100x100', '3000x3000'), function(err, _res, body) {
          axios.get(`https://itunes.apple.com/search?term=${artist} ${res.data.results[0].collectionName}&entity=album`).then(album => {
            log(chalk.green("✅　Retreived information!"));

            var tags = {
              title: res.data.results[0].trackName,
              artist: res.data.results[0].artistName,
              performerInfo: album.data.results[0].artistName,
              album: res.data.results[0].collectionName,
              copyright: album.data.results[0].copyright,
              year: new Date(res.data.results[0].releaseDate).getFullYear(),
              image: {
                mime: "jpeg",
                type: {
                  id: 3,
                  name: "front cover"
                },
                imageBuffer: body
              },
              fileType: "mp3",
              genre: res.data.results[0].primaryGenreName
            };

            log(chalk.yellow("✍🏻　Writing tags to mp3 file..."));

            id3.update(tags, filePath, () => {
              if (fs.existsSync(filePath) && process.platform === "darwin" && !hasflag("no-itunes")) {
                log(chalk.yellow("🎵　Adding song to Apple Music library..."));
                cp.execSync(`cp "${filePath}" "/Users/job/Music/Music/Media/Automatically\ Add\ to\ Music.localized"`);
              }
              
              log(chalk.green(`✅　Successfully downloaded ${info.title}.mp3!\n`));

              process.exit();
            });
          });
        });
      });
    } else {
      log(chalk.green(`✅　Successfully downloaded ${info.title}.mp3!`));

      process.exit();
    }
  });
});