text: //
  //  authenticationService.h
  //  Griddler
  //
  //  Copyright 2013 Google Inc. All Rights Reserved.
  //
  //  Licensed under the Apache License, Version 2.0 (the "License");
  //  you may not use this file except in compliance with the License.
  //  You may obtain a copy of the License at
  //
  //  http://www.apache.org/licenses/LICENSE-2.0
  //
  //  Unless required by applicable law or agreed to in writing, software
  //  distributed under the License is distributed on an "AS IS" BASIS,
  //  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  //  See the License for the specific language governing permissions and
  //  limitations under the License.
  //
  
  #import <UIKit/UIKit.h>
  #import "GTMOAuth2Authentication.h"
  #import "GPPSignIn.h"
  
  /**
   * The purpose of this intface is to expose functionality
   * around authenticating with a Google account
   **/
  @interface AuthenticationService : NSObject
  
  ///Returns YES if the current user is logged in
  - (BOOL)isLoggedIn;
  
  ///Begin the authentication process
  - (void)authenticate;
  
  ///Get the authorization keychain
  + (GTMOAuth2Authentication*)authFromKeychain;
  
  ///Get the currently logged in user's email address
  + (NSString *)googleAccountEmail;
  
  @end
  
  