matteomanzo/Playlister

//Modules
var querystring = require('querystring');
var request = require('request');
var SpotifyWebApi = require('spotify-web-api-node');
//Modules
var helpersDatabase = require('./helpersDatabase');
//Spotify
var clientId = process.env.SPOTIFY_CLIENT_ID;
var clientSecret = process.env.SPOTIFY_CLIENT_SECRET;
var redirect_uri_authorize = process.env.SPOTIFY_AUTHORIZE_CALLBACK;
var stateKey = 'spotify_auth_state';

//functions called by controllers
exports.authorizeSpotify = function(req, res) {
  var state = generateRandomString(16);
  res.cookie(stateKey, state);
  // your application requests authorization
  var scope = 'playlist-modify-public playlist-modify-private';
  res.redirect('https://accounts.spotify.com/authorize?' +
    querystring.stringify({response_type: 'code',
                          client_id: clientId,
                          scope: scope,
                          redirect_uri: redirect_uri_authorize,
                          state: state})
              );
};

exports.authorizeSpotifyCallback = function(req, res) {
  // your application requests refresh and access tokens
  // after checking the state parameter
  var code = req.query.code || null;
  var state = req.query.state || null;
  var storedState = req.cookies ? req.cookies[stateKey] : null;

  if (state === null || state !== storedState) {
    res.redirect('/#' + querystring.stringify({error: 'state_mismatch'}));
  }
  else {
    res.clearCookie(stateKey);
    var authOptions = {
      url:      'https://accounts.spotify.com/api/token',
      form:     {code: code,
                redirect_uri: redirect_uri_authorize,
                grant_type: 'authorization_code'},
      headers:  {'Authorization': 'Basic ' +
                (new Buffer(clientId + ':' + clientSecret).toString('base64'))},
      json:     true
    };

    request.post(authOptions, function(error, response, body) {
      if (!error && response.statusCode === 200) {
          var spotifyAccessToken = body.access_token;
          var spotifyRefreshToken = body.refresh_token;
          var options = {
          url: 'https://api.spotify.com/v1/me',
          headers: { 'Authorization': 'Bearer ' + spotifyAccessToken },
          json: true
          };

        // use access token to get party planner credentials from Spotify API
        request.get(options, function(error, response, body) {
          var spotifyID = body.id;
          saveTokensToDatabase(spotifyID, spotifyAccessToken, spotifyRefreshToken);
          res.redirect('/partyplanner/beacon/' + spotifyID );
          });
      }
      else {
        res.redirect('/' + querystring.stringify({error: 'invalid_token'}));
      }
    });
  }
};

exports.saveBeacon = function(spotifyID, beaconMajor, beaconMinor) {
  var collectionName = 'ppBeacon';
  var collectionObject = {"spotifyID" : spotifyID,
                          "beaconMajor" : beaconMajor,
                          "beaconMinor" : beaconMinor};
  helpersDatabase.saveToDatabase(collectionName, collectionObject);
};

exports.saveEventDetails = function(partyName, partyDate, playlistName, spotifyID) {
  //First find party planners Spotify Credentials
  var partyName = partyName;
  var partyDate = partyDate;
  var playlistName = playlistName;
  var spotifyID = spotifyID;
  moduleSaveEventDetails = require('./moduleSaveEventDetails');
  moduleSaveEventDetails.retrieveSpotifyCredentials(partyName, partyDate, playlistName, spotifyID);
};


//helper functions

/**
  * Used in Spotify Authorization to generate a required state variable
  * Generates a random string containing numbers and letters
  * @param  {number} length The length of the string
  * @return {string} The generated string
  */
var generateRandomString = function(length) {
  var text = '';
  var possible = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789';
  for (var i = 0; i < length; i++) {
    text += possible.charAt(Math.floor(Math.random() * possible.length));
  }
  return text;
};

var saveTokensToDatabase = function(spotifyID, spotifyAccessToken, spotifyRefreshToken) {
  var collectionName = 'ppSpotifyCredentials';
  var collectionObject = {"spotifyID" : spotifyID,
                          "spotifyAccessToken"  : spotifyAccessToken,
                          "spotifyRefreshToken" : spotifyRefreshToken};
  helpersDatabase.saveToDatabase(collectionName, collectionObject);
};