// 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/syncable.h"

namespace browser_sync {

using sessions::SyncSession;

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

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

  syncable::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 (syncable::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 syncable::FullModelTypeSet server_types_with_unapplied_updates =
      dir->GetServerTypesWithUnappliedUpdates(&trans);
  syncable::FullModelTypeSet server_type_restriction;
  for (syncable::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());
    }
  }

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

  UpdateApplicator applicator(
      session->context()->resolver(),
      dir->GetCryptographer(&trans),
      handles.begin(), handles.end(), session->routing_info(),
      session->status_controller().group_restriction());
  while (applicator.AttemptOneApplication(&trans)) {}
  applicator.SaveProgressIntoSessionState(
      session->mutable_status_controller()->mutable_conflict_progress(),
      session->mutable_status_controller()->mutable_update_progress());

  // 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 (syncable::ModelTypeSet::Iterator it =
             status.updates_request_types().First(); it.Good(); it.Inc()) {
      // This gets persisted to the directory's backing store.
      dir->set_initial_sync_ended_for_type(it.Get(), true);
    }
  }

  return SYNCER_OK;
}

}  // namespace browser_sync