// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef CHROME_BROWSER_GOOGLE_APIS_AUTH_SERVICE_INTERFACE_H_
#define CHROME_BROWSER_GOOGLE_APIS_AUTH_SERVICE_INTERFACE_H_

#include <string>

#include "chrome/browser/google_apis/base_operations.h"
#include "chrome/browser/google_apis/gdata_errorcode.h"

class Profile;

namespace google_apis {

class OperationRegistry;
class AuthServiceObserver;

// Called when fetching of access token is complete.
typedef base::Callback<void(GDataErrorCode error,
                            const std::string& access_token)>
    AuthStatusCallback;

// This defines an interface for the authentication service which is required
// by authenticated operations (AuthenticatedOperationInterface).
// All functions must be called on UI thread.
class AuthServiceInterface {
 public:
  // Adds and removes the observer. AddObserver() should be called before
  // Initialize() as it can change the refresh token.
  virtual void AddObserver(AuthServiceObserver* observer) = 0;
  virtual void RemoveObserver(AuthServiceObserver* observer) = 0;

  // Initializes the auth service. Starts TokenService to retrieve the
  // refresh token.
  virtual void Initialize(Profile* profile) = 0;

  // Starts fetching OAuth2 access token from the refresh token.
  // |callback| must not be null.
  virtual void StartAuthentication(OperationRegistry* registry,
                                   const AuthStatusCallback& callback) = 0;

  // True if an OAuth2 access token is retrieved and believed to be fresh.
  // The access token is used to access the Drive server.
  virtual bool HasAccessToken() const = 0;

  // True if an OAuth2 refresh token is present. Its absence means that user
  // is not properly authenticated.
  // The refresh token is used to get the access token.
  virtual bool HasRefreshToken() const = 0;

  // Returns OAuth2 access token.
  virtual const std::string& access_token() const = 0;

  // Clears OAuth2 access token.
  virtual void ClearAccessToken() = 0;
};

}  // namespace google_apis

#endif  // CHROME_BROWSER_GOOGLE_APIS_AUTH_SERVICE_INTERFACE_H_