var google = require('googleapis');
var _ = require('lodash-node/compat');
var Q = require('q');
var OAuth2 = google.auth.OAuth2;


var CLIENT_ID = '...';
var CLIENT_SECRET = '...';
var REDIRECT_URL = '...';

var shareFile = function (fileName) {
  var deferred = Q.defer();
  var drive = google.drive('v2');
  var auth = new OAuth2(CLIENT_ID, CLIENT_SECRET, REDIRECT_URL);

  drive.files.list({auth: auth}, function (err, res) {
    var foundFile = _.first(_.filter(res.items, {title: fileName, "explicitlyTrashed": false}));

    if (!foundFile) {
        deferred.reject('File ' + fileName + ' has not been found.');
        return;
    }

    drive.permissions.list({fileId: foundFile.id, auth: auth}, function (err, res) {

        if (_.isEmpty(_.find(res.items, 'role', 'reader'))) {
            var body = {
                'value': 'default',
                'type': 'anyone',
                'role': 'reader'
            };

            drive.permissions.insert({
                fileId: foundFile.id,
                resource: body,
                auth: auth
            }, function (err, res, body) {
                deferred.resolve(body);
            });
        }
    });
});
return deferred.promise;