// 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.

#include "sync/engine/apply_updates_command.h"

#include "base/location.h"
#include "sync/engine/update_applicator.h"
#include "sync/sessions/sync_session.h"
#include "sync/syncable/directory.h"
#include "sync/syncable/read_transaction.h"
#include "sync/syncable/write_transaction.h"

namespace syncer {

using sessions::SyncSession;

ApplyUpdatesCommand::ApplyUpdatesCommand() {}
ApplyUpdatesCommand::~ApplyUpdatesCommand() {}

std::set<ModelSafeGroup> ApplyUpdatesCommand::GetGroupsToChange(
    const sessions::SyncSession& session) const {
  std::set<ModelSafeGroup> groups_with_unapplied_updates;

  FullModelTypeSet server_types_with_unapplied_updates;
  {
    syncable::Directory* dir = session.context()->directory();
    syncable::ReadTransaction trans(FROM_HERE, dir);
    server_types_with_unapplied_updates =
        dir->GetServerTypesWithUnappliedUpdates(&trans);
  }

  for (FullModelTypeSet::Iterator it =
           server_types_with_unapplied_updates.First(); it.Good(); it.Inc()) {
    groups_with_unapplied_updates.insert(
        GetGroupForModelType(it.Get(), session.routing_info()));
  }

  return groups_with_unapplied_updates;
}

SyncerError ApplyUpdatesCommand::ModelChangingExecuteImpl(
    SyncSession* session) {
  syncable::Directory* dir = session->context()->directory();
  syncable::WriteTransaction trans(FROM_HERE, syncable::SYNCER, dir);

  // Compute server types with unapplied updates that fall under our
  // group restriction.
  const FullModelTypeSet server_types_with_unapplied_updates =
      dir->GetServerTypesWithUnappliedUpdates(&trans);
  FullModelTypeSet server_type_restriction;
  for (FullModelTypeSet::Iterator it =
           server_types_with_unapplied_updates.First(); it.Good(); it.Inc()) {
    if (GetGroupForModelType(it.Get(), session->routing_info()) ==
        session->status_controller().group_restriction()) {
      server_type_restriction.Put(it.Get());
    }
  }

  // Don't process control type updates here.  They will be handled elsewhere.
  FullModelTypeSet control_types = ToFullModelTypeSet(ControlTypes());
  server_type_restriction.RemoveAll(control_types);

  std::vector<int64> handles;
  dir->GetUnappliedUpdateMetaHandles(
      &trans, server_type_restriction, &handles);

  UpdateApplicator applicator(
      dir->GetCryptographer(&trans),
      session->routing_info(),
      session->status_controller().group_restriction());
  applicator.AttemptApplications(&trans, handles,
                                 session->mutable_status_controller());

  // This might be the first time we've fully completed a sync cycle, for
  // some subset of the currently synced datatypes.
  const sessions::StatusController& status(session->status_controller());
  if (status.ServerSaysNothingMoreToDownload()) {
    for (ModelTypeSet::Iterator it =
             status.updates_request_types().First(); it.Good(); it.Inc()) {
      // Don't set the flag for control types.  We didn't process them here.
      if (IsControlType(it.Get()))
        continue;

      // This gets persisted to the directory's backing store.
      dir->set_initial_sync_ended_for_type(it.Get(), true);
    }
  }

  return SYNCER_OK;
}

}  // namespace syncer