// Copyright 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_SYNC_ENGINE_IMPL_GET_UPDATES_PROCESSOR_H_
#define COMPONENTS_SYNC_ENGINE_IMPL_GET_UPDATES_PROCESSOR_H_

#include <map>
#include <vector>

#include "base/gtest_prod_util.h"
#include "base/macros.h"
#include "components/sync/base/model_type.h"
#include "components/sync/engine/model_safe_worker.h"
#include "components/sync/engine_impl/model_type_registry.h"
#include "components/sync/protocol/sync.pb.h"

namespace sync_pb {
class GetUpdatesResponse;
}  // namespace sync_pb

namespace syncer {

class DebugInfoGetter;
class GetUpdatesDelegate;
class StatusController;
class SyncCycle;

// This class manages the set of per-type syncer objects.
//
// It owns these types and hides the details of iterating over all of them.
// Most methods allow the caller to specify a subset of types on which the
// operation is to be applied.  It is a logic error if the supplied set of types
// contains a type which was not previously registered with the manager.
class GetUpdatesProcessor {
 public:
  explicit GetUpdatesProcessor(UpdateHandlerMap* update_handler_map,
                               const GetUpdatesDelegate& delegate);
  ~GetUpdatesProcessor();

  // Downloads and processes a batch of updates for the specified types.
  //
  // Returns SYNCER_OK if the download succeeds, SERVER_MORE_TO_DOWNLOAD if the
  // download succeeded but there are still some updates left to fetch on the
  // server, or an appropriate error value in case of failure.
  SyncerError DownloadUpdates(ModelTypeSet* request_types, SyncCycle* cycle);

  // Applies any downloaded and processed updates.
  void ApplyUpdates(const ModelTypeSet& gu_types,
                    StatusController* status_controller);

 private:
  // Populates a GetUpdates request message with per-type information.
  void PrepareGetUpdates(const ModelTypeSet& gu_types,
                         sync_pb::ClientToServerMessage* message);

  // Sends the specified message to the server and stores the response in a
  // member of the |cycle|'s StatusController.
  SyncerError ExecuteDownloadUpdates(ModelTypeSet* request_types,
                                     SyncCycle* cycle,
                                     sync_pb::ClientToServerMessage* msg);

  // Helper function for processing responses from the server.  Defined here for
  // testing.
  SyncerError ProcessResponse(const sync_pb::GetUpdatesResponse& gu_response,
                              const ModelTypeSet& proto_request_types,
                              StatusController* status);

  // Processes a GetUpdates responses for each type.
  SyncerError ProcessGetUpdatesResponse(
      const ModelTypeSet& gu_types,
      const sync_pb::GetUpdatesResponse& gu_response,
      StatusController* status_controller);

  static void CopyClientDebugInfo(DebugInfoGetter* debug_info_getter,
                                  sync_pb::DebugInfo* debug_info);

  FRIEND_TEST_ALL_PREFIXES(GetUpdatesProcessorTest, BookmarkNudge);
  FRIEND_TEST_ALL_PREFIXES(GetUpdatesProcessorTest, NotifyMany);
  FRIEND_TEST_ALL_PREFIXES(GetUpdatesProcessorTest, InitialSyncRequest);
  FRIEND_TEST_ALL_PREFIXES(GetUpdatesProcessorTest, ConfigureTest);
  FRIEND_TEST_ALL_PREFIXES(GetUpdatesProcessorTest, PollTest);
  FRIEND_TEST_ALL_PREFIXES(GetUpdatesProcessorTest, RetryTest);
  FRIEND_TEST_ALL_PREFIXES(GetUpdatesProcessorTest, NudgeWithRetryTest);
  FRIEND_TEST_ALL_PREFIXES(GetUpdatesProcessorTest, InvalidResponse);
  FRIEND_TEST_ALL_PREFIXES(GetUpdatesProcessorTest, MoreToDownloadResponse);
  FRIEND_TEST_ALL_PREFIXES(GetUpdatesProcessorTest, NormalResponseTest);
  FRIEND_TEST_ALL_PREFIXES(DownloadUpdatesDebugInfoTest,
                           VerifyCopyClientDebugInfo_Empty);
  FRIEND_TEST_ALL_PREFIXES(DownloadUpdatesDebugInfoTest, VerifyCopyOverwrites);

  // A map of 'update handlers', one for each enabled type.
  // This must be kept in sync with the routing info.  Our temporary solution to
  // that problem is to initialize this map in set_routing_info().
  UpdateHandlerMap* update_handler_map_;

  const GetUpdatesDelegate& delegate_;

  DISALLOW_COPY_AND_ASSIGN(GetUpdatesProcessor);
};

}  // namespace syncer

#endif  // COMPONENTS_SYNC_ENGINE_IMPL_GET_UPDATES_PROCESSOR_H_