// Copyright (c) 2014 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 COMPONENTS_GCM_DRIVER_GCM_APP_HANDLER_H_
#define COMPONENTS_GCM_DRIVER_GCM_APP_HANDLER_H_

#include <string>

#include "components/gcm_driver/gcm_client.h"

namespace gcm {

// Defines the interface to provide handling and event routing logic for a given
// app.
class GCMAppHandler {
 public:
  GCMAppHandler();
  virtual ~GCMAppHandler();

  // Called to do all the cleanup when GCM is shutting down.
  // In the case that multiple apps share the same app handler, it should be
  // make safe for ShutdownHandler to be called multiple times.
  virtual void ShutdownHandler() = 0;

  // Called when the GCM store is reset (e.g. due to corruption), which changes
  // the device ID, invalidating all prior registrations. Any stored state
  // related to GCM registrations or InstanceIDs should be deleted. This should
  // only be considered a defense in depth, as this method will not be called if
  // the store is reset before this app handler is registered; hence it is
  // recommended to regularly revalidate any stored registrations/InstanceIDs.
  // TODO(johnme): GCMDriver doesn't yet provide an API for revalidating them.
  virtual void OnStoreReset() = 0;

  // Called when a GCM message has been received.
  virtual void OnMessage(const std::string& app_id,
                         const IncomingMessage& message) = 0;

  // Called when some GCM messages have been deleted from the server.
  virtual void OnMessagesDeleted(const std::string& app_id) = 0;

  // Called when a GCM message failed to be delivered.
  virtual void OnSendError(
      const std::string& app_id,
      const GCMClient::SendErrorDetails& send_error_details) = 0;

  // Called when a GCM message was received by GCM server.
  virtual void OnSendAcknowledged(const std::string& app_id,
                                  const std::string& message_id) = 0;

  // Called when a GCM message has been received but decryption failed.
  // |message_id| is a message identifier sent by the GCM server.
  // |error_message| is human-readable description of the error, for reporting
  // purposes. By default this handler does nothing.
  virtual void OnMessageDecryptionFailed(const std::string& app_id,
                                         const std::string& message_id,
                                         const std::string& error_message);

  // If no app handler has been added with the exact app_id of an incoming
  // event, all handlers will be asked (in arbitrary order) whether they can
  // handle the app_id, and the first to return true will receive the event.
  virtual bool CanHandle(const std::string& app_id) const;
};

}  // namespace gcm

#endif  // COMPONENTS_GCM_DRIVER_GCM_APP_HANDLER_H_