var SpotifyWebApi = require('spotify-web-api-node');

function Spotify(config) {
  // Set up initial state
  this.config = config;

  this.credentials = {
    clientId: this.config.clientId,
    clientSecret: this.config.clientSecret,
    redirectUri: this.config.redirectUri
  };

  const spotifyApi = new SpotifyWebApi(this.credentials);

  // The code that's returned as a query parameter to the redirect URI
  const code = this.config.userCode;

  this.init = () => {
    return new Promise((resolve, reject) => {
      // Retrieve an access token and a refresh token
      spotifyApi.authorizationCodeGrant(code).then(
        function(data) {
          console.log('The token expires in ' + data.body['expires_in']);
          console.log('The access token is ' + data.body['access_token']);
          console.log('The refresh token is ' + data.body['refresh_token']);

          // Set the access token on the API object to use it in later calls
          spotifyApi.setAccessToken(data.body['access_token']);
          spotifyApi.setRefreshToken(data.body['refresh_token']);

          // clientId, clientSecret and refreshToken has been set on the api object previous to this call.
          setInterval(() => {
            spotifyApi.refreshAccessToken().then(
              function(data) {
                console.log('The access token has been refreshed!');

                // Save the access token so that it's used in future calls
                spotifyApi.setAccessToken(data.body['access_token']);
              },
              function(err) {
                console.log('Could not refresh access token', err);
              }
            );
          }, data.body['expires_in']*1000);

          resolve();
        },
        function(err) {
          console.log('Something went wrong!', JSON.stringify(err));
          reject(err);
        }
      );
    });
  };

  this.getMe = () => {
    spotifyApi.getMe()
    .then(function(data) {
      console.log('Some information about the authenticated user', data.body);
    }, function(err) {
      console.log('Something went wrong!', err);
    });
  };

  this.getCurrentSong = () => {
    return new Promise((resolve, reject) => {
      spotifyApi.getMyCurrentPlaybackState({}, (err, data) => {
        if (err) {
          reject(err);
          return;
        }

        let state = data.body;
        resolve({
          artists: state.item.artists,
          name: state.item.name,
          album: state.item.album.name,
          url: state.item.external_urls.spotify
        });
      });
    });
  };

  this.getCurrentPlaylist = () => {
    return new Promise((resolve, reject) => {
      spotifyApi.getMyCurrentPlaybackState({}, (err, data) => {
        if (err) {
          reject(err);
          return;
        }

        let state = data.body;
        if (state.context) {
          resolve(state.context.external_urls.spotify);
        } else {
          resolve(state.item.album.external_urls.spotify);
        }
      });
    });
  };

  this.skip = () => {
    return spotifyApi.skipToNext();
  };

  this.pause = () => {
    return spotifyApi.pause();
  };

  this.resume = () => {
    return spotifyApi.play();
  };

  this.setVolume = (volume) => {
    volume = parseInt(volume);
    if (volume < 0) volume = 0;
    if (volume > 100) volume = 100;
    return spotifyApi.setVolume(volume);
  };
}

module.exports = Spotify;