// 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 "chrome/browser/chromeos/settings/device_settings_provider.h"

#include "base/bind.h"
#include "base/bind_helpers.h"
#include "base/callback.h"
#include "base/file_util.h"
#include "base/logging.h"
#include "base/string_util.h"
#include "base/threading/thread_restrictions.h"
#include "base/values.h"
#include "chrome/browser/browser_process.h"
#include "chrome/browser/chromeos/cros/cros_library.h"
#include "chrome/browser/chromeos/cros/network_library.h"
#include "chrome/browser/chromeos/settings/cros_settings.h"
#include "chrome/browser/chromeos/settings/cros_settings_names.h"
#include "chrome/browser/chromeos/settings/device_settings_cache.h"
#include "chrome/browser/policy/app_pack_updater.h"
#include "chrome/browser/policy/browser_policy_connector.h"
#include "chrome/browser/policy/cloud_policy_constants.h"
#include "chrome/browser/policy/proto/device_management_backend.pb.h"
#include "chrome/browser/ui/options/options_util.h"
#include "chrome/installer/util/google_update_settings.h"

using google::protobuf::RepeatedPtrField;

namespace em = enterprise_management;

namespace chromeos {

namespace {

// List of settings handled by the DeviceSettingsProvider.
const char* kKnownSettings[] = {
  kAccountsPrefAllowGuest,
  kAccountsPrefAllowNewUser,
  kAccountsPrefEphemeralUsersEnabled,
  kAccountsPrefShowUserNamesOnSignIn,
  kAccountsPrefUsers,
  kAppPack,
  kDeviceOwner,
  kIdleLogoutTimeout,
  kIdleLogoutWarningDuration,
  kPolicyMissingMitigationMode,
  kReleaseChannel,
  kReleaseChannelDelegated,
  kReportDeviceActivityTimes,
  kReportDeviceBootMode,
  kReportDeviceLocation,
  kReportDeviceVersionInfo,
  kScreenSaverExtensionId,
  kScreenSaverTimeout,
  kSettingProxyEverywhere,
  kSignedDataRoamingEnabled,
  kStartUpUrls,
  kStatsReportingPref,
  kSystemTimezonePolicy,
};

// Legacy policy file location. Used to detect migration from pre v12 ChromeOS.
const char kLegacyPolicyFile[] = "/var/lib/whitelist/preferences";

bool IsControlledSetting(const std::string& pref_path) {
  const char** end = kKnownSettings + arraysize(kKnownSettings);
  return std::find(kKnownSettings, end, pref_path) != end;
}

bool HasOldMetricsFile() {
  // TODO(pastarmovj): Remove this once migration is not needed anymore.
  // If the value is not set we should try to migrate legacy consent file.
  // Loading consent file state causes us to do blocking IO on UI thread.
  // Temporarily allow it until we fix http://crbug.com/62626
  base::ThreadRestrictions::ScopedAllowIO allow_io;
  return GoogleUpdateSettings::GetCollectStatsConsent();
}

}  // namespace

DeviceSettingsProvider::DeviceSettingsProvider(
    const NotifyObserversCallback& notify_cb,
    DeviceSettingsService* device_settings_service)
    : CrosSettingsProvider(notify_cb),
      device_settings_service_(device_settings_service),
      trusted_status_(TEMPORARILY_UNTRUSTED),
      ownership_status_(device_settings_service_->GetOwnershipStatus()),
      ALLOW_THIS_IN_INITIALIZER_LIST(store_callback_factory_(this)) {
  device_settings_service_->AddObserver(this);

  if (!UpdateFromService()) {
    // Make sure we have at least the cache data immediately.
    RetrieveCachedData();
  }
}

DeviceSettingsProvider::~DeviceSettingsProvider() {
  device_settings_service_->RemoveObserver(this);
}

void DeviceSettingsProvider::DoSet(const std::string& path,
                                   const base::Value& in_value) {
  // Make sure that either the current user is the device owner or the
  // device doesn't have an owner yet.
  if (!(device_settings_service_->HasPrivateOwnerKey() ||
        ownership_status_ == DeviceSettingsService::OWNERSHIP_NONE)) {
    LOG(WARNING) << "Changing settings from non-owner, setting=" << path;

    // Revert UI change.
    NotifyObservers(path);
    return;
  }

  if (IsControlledSetting(path)) {
    pending_changes_.push_back(PendingQueueElement(path, in_value.DeepCopy()));
    if (!store_callback_factory_.HasWeakPtrs())
      SetInPolicy();
  } else {
    NOTREACHED() << "Try to set unhandled cros setting " << path;
  }
}

void DeviceSettingsProvider::OwnershipStatusChanged() {
  DeviceSettingsService::OwnershipStatus new_ownership_status =
      device_settings_service_->GetOwnershipStatus();

  // If the device just became owned, write the settings accumulated in the
  // cache to device settings proper. It is important that writing only happens
  // in this case, as during normal operation, the contents of the cache should
  // never overwrite actual device settings.
  if (new_ownership_status == DeviceSettingsService::OWNERSHIP_TAKEN &&
      ownership_status_ == DeviceSettingsService::OWNERSHIP_NONE &&
      device_settings_service_->HasPrivateOwnerKey()) {

    // There shouldn't be any pending writes, since the cache writes are all
    // immediate.
    DCHECK(!store_callback_factory_.HasWeakPtrs());

    // Apply the locally-accumulated device settings on top of the initial
    // settings from the service and write back the result.
    if (device_settings_service_->device_settings()) {
      em::ChromeDeviceSettingsProto new_settings(
          *device_settings_service_->device_settings());
      new_settings.MergeFrom(device_settings_);
      device_settings_.Swap(&new_settings);
    }
    StoreDeviceSettings();
  }

  // The owner key might have become available, allowing migration to happen.
  AttemptMigration();

  ownership_status_ = new_ownership_status;
}

void DeviceSettingsProvider::DeviceSettingsUpdated() {
  if (!store_callback_factory_.HasWeakPtrs())
    UpdateAndProceedStoring();
}

void DeviceSettingsProvider::RetrieveCachedData() {
  em::PolicyData policy_data;
  if (!device_settings_cache::Retrieve(&policy_data,
                                       g_browser_process->local_state()) ||
      !device_settings_.ParseFromString(policy_data.policy_value())) {
    VLOG(1) << "Can't retrieve temp store, possibly not created yet.";
  }

  UpdateValuesCache(policy_data, device_settings_);
}

void DeviceSettingsProvider::SetInPolicy() {
  if (pending_changes_.empty()) {
    NOTREACHED();
    return;
  }

  if (RequestTrustedEntity() != TRUSTED) {
    // Re-sync device settings before proceeding.
    device_settings_service_->Load();
    return;
  }

  std::string prop(pending_changes_.front().first);
  scoped_ptr<base::Value> value(pending_changes_.front().second);
  pending_changes_.pop_front();

  trusted_status_ = TEMPORARILY_UNTRUSTED;
  if (prop == kAccountsPrefAllowNewUser) {
    em::AllowNewUsersProto* allow =
        device_settings_.mutable_allow_new_users();
    bool allow_value;
    if (value->GetAsBoolean(&allow_value))
      allow->set_allow_new_users(allow_value);
    else
      NOTREACHED();
  } else if (prop == kAccountsPrefAllowGuest) {
    em::GuestModeEnabledProto* guest =
        device_settings_.mutable_guest_mode_enabled();
    bool guest_value;
    if (value->GetAsBoolean(&guest_value))
      guest->set_guest_mode_enabled(guest_value);
    else
      NOTREACHED();
  } else if (prop == kAccountsPrefShowUserNamesOnSignIn) {
    em::ShowUserNamesOnSigninProto* show =
        device_settings_.mutable_show_user_names();
    bool show_value;
    if (value->GetAsBoolean(&show_value))
      show->set_show_user_names(show_value);
    else
      NOTREACHED();
  } else if (prop == kSignedDataRoamingEnabled) {
    em::DataRoamingEnabledProto* roam =
        device_settings_.mutable_data_roaming_enabled();
    bool roaming_value = false;
    if (value->GetAsBoolean(&roaming_value))
      roam->set_data_roaming_enabled(roaming_value);
    else
      NOTREACHED();
    ApplyRoamingSetting(roaming_value);
  } else if (prop == kSettingProxyEverywhere) {
    // TODO(cmasone): NOTIMPLEMENTED() once http://crosbug.com/13052 is fixed.
    std::string proxy_value;
    if (value->GetAsString(&proxy_value)) {
      bool success =
          device_settings_.mutable_device_proxy_settings()->ParseFromString(
              proxy_value);
      DCHECK(success);
    } else {
      NOTREACHED();
    }
  } else if (prop == kReleaseChannel) {
    em::ReleaseChannelProto* release_channel =
        device_settings_.mutable_release_channel();
    std::string channel_value;
    if (value->GetAsString(&channel_value))
      release_channel->set_release_channel(channel_value);
    else
      NOTREACHED();
  } else if (prop == kStatsReportingPref) {
    em::MetricsEnabledProto* metrics =
        device_settings_.mutable_metrics_enabled();
    bool metrics_value = false;
    if (value->GetAsBoolean(&metrics_value))
      metrics->set_metrics_enabled(metrics_value);
    else
      NOTREACHED();
    ApplyMetricsSetting(false, metrics_value);
  } else if (prop == kAccountsPrefUsers) {
    em::UserWhitelistProto* whitelist_proto =
        device_settings_.mutable_user_whitelist();
    whitelist_proto->clear_user_whitelist();
    base::ListValue& users = static_cast<base::ListValue&>(*value);
    for (base::ListValue::const_iterator i = users.begin();
         i != users.end(); ++i) {
      std::string email;
      if ((*i)->GetAsString(&email))
        whitelist_proto->add_user_whitelist(email.c_str());
    }
  } else if (prop == kAccountsPrefEphemeralUsersEnabled) {
    em::EphemeralUsersEnabledProto* ephemeral_users_enabled =
        device_settings_.mutable_ephemeral_users_enabled();
    bool ephemeral_users_enabled_value = false;
    if (value->GetAsBoolean(&ephemeral_users_enabled_value)) {
      ephemeral_users_enabled->set_ephemeral_users_enabled(
          ephemeral_users_enabled_value);
    } else {
      NOTREACHED();
    }
  } else {
    // The remaining settings don't support Set(), since they are not
    // intended to be customizable by the user:
    //   kAppPack
    //   kDeviceOwner
    //   kIdleLogoutTimeout
    //   kIdleLogoutWarningDuration
    //   kReleaseChannelDelegated
    //   kReportDeviceVersionInfo
    //   kReportDeviceActivityTimes
    //   kReportDeviceBootMode
    //   kReportDeviceLocation
    //   kScreenSaverExtensionId
    //   kScreenSaverTimeout
    //   kStartUpUrls
    //   kSystemTimezonePolicy

    LOG(FATAL) << "Device setting " << prop << " is read-only.";
  }

  em::PolicyData data;
  data.set_username(device_settings_service_->GetUsername());
  CHECK(device_settings_.SerializeToString(data.mutable_policy_value()));

  // Set the cache to the updated value.
  UpdateValuesCache(data, device_settings_);

  if (!device_settings_cache::Store(data, g_browser_process->local_state()))
    LOG(ERROR) << "Couldn't store to the temp storage.";

  if (ownership_status_ == DeviceSettingsService::OWNERSHIP_TAKEN) {
    StoreDeviceSettings();
  } else {
    // OnStorePolicyCompleted won't get called in this case so proceed with any
    // pending operations immediately.
    if (!pending_changes_.empty())
      SetInPolicy();
  }
}

void DeviceSettingsProvider::DecodeLoginPolicies(
    const em::ChromeDeviceSettingsProto& policy,
    PrefValueMap* new_values_cache) const {
  // For all our boolean settings the following is applicable:
  // true is default permissive value and false is safe prohibitive value.
  // Exceptions:
  //   kSignedDataRoamingEnabled has a default value of false.
  //   kAccountsPrefEphemeralUsersEnabled has a default value of false.
  if (policy.has_allow_new_users() &&
      policy.allow_new_users().has_allow_new_users() &&
      policy.allow_new_users().allow_new_users()) {
    // New users allowed, user_whitelist() ignored.
    new_values_cache->SetBoolean(kAccountsPrefAllowNewUser, true);
  } else if (!policy.has_user_whitelist()) {
    // If we have the allow_new_users bool, and it is true, we honor that above.
    // In all other cases (don't have it, have it and it is set to false, etc),
    // We will honor the user_whitelist() if it is there and populated.
    // Otherwise we default to allowing new users.
    new_values_cache->SetBoolean(kAccountsPrefAllowNewUser, true);
  } else {
    new_values_cache->SetBoolean(
        kAccountsPrefAllowNewUser,
        policy.user_whitelist().user_whitelist_size() == 0);
  }

  new_values_cache->SetBoolean(
      kAccountsPrefAllowGuest,
      !policy.has_guest_mode_enabled() ||
      !policy.guest_mode_enabled().has_guest_mode_enabled() ||
      policy.guest_mode_enabled().guest_mode_enabled());

  new_values_cache->SetBoolean(
      kAccountsPrefShowUserNamesOnSignIn,
      !policy.has_show_user_names() ||
      !policy.show_user_names().has_show_user_names() ||
      policy.show_user_names().show_user_names());

  new_values_cache->SetBoolean(
      kAccountsPrefEphemeralUsersEnabled,
      policy.has_ephemeral_users_enabled() &&
      policy.ephemeral_users_enabled().has_ephemeral_users_enabled() &&
      policy.ephemeral_users_enabled().ephemeral_users_enabled());

  base::ListValue* list = new base::ListValue();
  const em::UserWhitelistProto& whitelist_proto = policy.user_whitelist();
  const RepeatedPtrField<std::string>& whitelist =
      whitelist_proto.user_whitelist();
  for (RepeatedPtrField<std::string>::const_iterator it = whitelist.begin();
       it != whitelist.end(); ++it) {
    list->Append(base::Value::CreateStringValue(*it));
  }
  new_values_cache->SetValue(kAccountsPrefUsers, list);
}

void DeviceSettingsProvider::DecodeKioskPolicies(
    const em::ChromeDeviceSettingsProto& policy,
    PrefValueMap* new_values_cache) const {
  if (policy.has_forced_logout_timeouts()) {
    if (policy.forced_logout_timeouts().has_idle_logout_timeout()) {
      new_values_cache->SetInteger(
          kIdleLogoutTimeout,
          policy.forced_logout_timeouts().idle_logout_timeout());
    }

    if (policy.forced_logout_timeouts().has_idle_logout_warning_duration()) {
      new_values_cache->SetInteger(
          kIdleLogoutWarningDuration,
          policy.forced_logout_timeouts().idle_logout_warning_duration());
    }
  }

  if (policy.has_login_screen_saver()) {
    if (policy.login_screen_saver().has_screen_saver_timeout()) {
      new_values_cache->SetInteger(
          kScreenSaverTimeout,
          policy.login_screen_saver().screen_saver_timeout());
    }

    if (policy.login_screen_saver().has_screen_saver_extension_id()) {
      new_values_cache->SetString(
          kScreenSaverExtensionId,
          policy.login_screen_saver().screen_saver_extension_id());
    }
  }

  if (policy.has_app_pack()) {
    typedef RepeatedPtrField<em::AppPackEntryProto> proto_type;
    base::ListValue* list = new base::ListValue;
    const proto_type& app_pack = policy.app_pack().app_pack();
    for (proto_type::const_iterator it = app_pack.begin();
         it != app_pack.end(); ++it) {
      base::DictionaryValue* entry = new base::DictionaryValue;
      if (it->has_extension_id()) {
        entry->SetString(policy::AppPackUpdater::kExtensionId,
                         it->extension_id());
      }
      if (it->has_update_url())
        entry->SetString(policy::AppPackUpdater::kUpdateUrl, it->update_url());
      list->Append(entry);
    }
    new_values_cache->SetValue(kAppPack, list);
  }

  if (policy.has_start_up_urls()) {
    base::ListValue* list = new base::ListValue();
    const em::StartUpUrlsProto& urls_proto = policy.start_up_urls();
    const RepeatedPtrField<std::string>& urls = urls_proto.start_up_urls();
    for (RepeatedPtrField<std::string>::const_iterator it = urls.begin();
         it != urls.end(); ++it) {
      list->Append(base::Value::CreateStringValue(*it));
    }
    new_values_cache->SetValue(kStartUpUrls, list);
  }
}

void DeviceSettingsProvider::DecodeNetworkPolicies(
    const em::ChromeDeviceSettingsProto& policy,
    PrefValueMap* new_values_cache) const {
  new_values_cache->SetBoolean(
      kSignedDataRoamingEnabled,
      policy.has_data_roaming_enabled() &&
      policy.data_roaming_enabled().has_data_roaming_enabled() &&
      policy.data_roaming_enabled().data_roaming_enabled());

  // TODO(cmasone): NOTIMPLEMENTED() once http://crosbug.com/13052 is fixed.
  std::string serialized;
  if (policy.has_device_proxy_settings() &&
      policy.device_proxy_settings().SerializeToString(&serialized)) {
    new_values_cache->SetString(kSettingProxyEverywhere, serialized);
  }
}

void DeviceSettingsProvider::DecodeReportingPolicies(
    const em::ChromeDeviceSettingsProto& policy,
    PrefValueMap* new_values_cache) const {
  if (policy.has_device_reporting()) {
    if (policy.device_reporting().has_report_version_info()) {
      new_values_cache->SetBoolean(
          kReportDeviceVersionInfo,
          policy.device_reporting().report_version_info());
    }
    if (policy.device_reporting().has_report_activity_times()) {
      new_values_cache->SetBoolean(
          kReportDeviceActivityTimes,
          policy.device_reporting().report_activity_times());
    }
    if (policy.device_reporting().has_report_boot_mode()) {
      new_values_cache->SetBoolean(
          kReportDeviceBootMode,
          policy.device_reporting().report_boot_mode());
    }
    // Device location reporting needs to pass privacy review before it can be
    // enabled. crosbug.com/24681
    // if (policy.device_reporting().has_report_location()) {
    //   new_values_cache->SetBoolean(
    //       kReportDeviceLocation,
    //       policy.device_reporting().report_location());
    // }
  }
}

void DeviceSettingsProvider::DecodeGenericPolicies(
    const em::ChromeDeviceSettingsProto& policy,
    PrefValueMap* new_values_cache) const {
  if (policy.has_metrics_enabled()) {
    new_values_cache->SetBoolean(kStatsReportingPref,
                                 policy.metrics_enabled().metrics_enabled());
  } else {
    new_values_cache->SetBoolean(kStatsReportingPref, HasOldMetricsFile());
  }

  if (!policy.has_release_channel() ||
      !policy.release_channel().has_release_channel()) {
    // Default to an invalid channel (will be ignored).
    new_values_cache->SetString(kReleaseChannel, "");
  } else {
    new_values_cache->SetString(kReleaseChannel,
                                policy.release_channel().release_channel());
  }

  new_values_cache->SetBoolean(
      kReleaseChannelDelegated,
      policy.has_release_channel() &&
      policy.release_channel().has_release_channel_delegated() &&
      policy.release_channel().release_channel_delegated());

  if (policy.has_system_timezone()) {
    if (policy.system_timezone().has_timezone()) {
      new_values_cache->SetString(
          kSystemTimezonePolicy,
          policy.system_timezone().timezone());
    }
  }
}

void DeviceSettingsProvider::UpdateValuesCache(
    const em::PolicyData& policy_data,
    const em::ChromeDeviceSettingsProto& settings) {
  PrefValueMap new_values_cache;

  if (policy_data.has_username() && !policy_data.has_request_token())
    new_values_cache.SetString(kDeviceOwner, policy_data.username());

  DecodeLoginPolicies(settings, &new_values_cache);
  DecodeKioskPolicies(settings, &new_values_cache);
  DecodeNetworkPolicies(settings, &new_values_cache);
  DecodeReportingPolicies(settings, &new_values_cache);
  DecodeGenericPolicies(settings, &new_values_cache);

  // Collect all notifications but send them only after we have swapped the
  // cache so that if somebody actually reads the cache will be already valid.
  std::vector<std::string> notifications;
  // Go through the new values and verify in the old ones.
  PrefValueMap::iterator iter = new_values_cache.begin();
  for (; iter != new_values_cache.end(); ++iter) {
    const base::Value* old_value;
    if (!values_cache_.GetValue(iter->first, &old_value) ||
        !old_value->Equals(iter->second)) {
      notifications.push_back(iter->first);
    }
  }
  // Now check for values that have been removed from the policy blob.
  for (iter = values_cache_.begin(); iter != values_cache_.end(); ++iter) {
    const base::Value* value;
    if (!new_values_cache.GetValue(iter->first, &value))
      notifications.push_back(iter->first);
  }
  // Swap and notify.
  values_cache_.Swap(&new_values_cache);
  for (size_t i = 0; i < notifications.size(); ++i)
    NotifyObservers(notifications[i]);
}

void DeviceSettingsProvider::ApplyMetricsSetting(bool use_file,
                                                 bool new_value) {
  // TODO(pastarmovj): Remove this once migration is not needed anymore.
  // If the value is not set we should try to migrate legacy consent file.
  if (use_file) {
    new_value = HasOldMetricsFile();
    // Make sure the values will get eventually written to the policy file.
    migration_values_.SetValue(kStatsReportingPref,
                               base::Value::CreateBooleanValue(new_value));
    AttemptMigration();
    LOG(INFO) << "No metrics policy set will revert to checking "
              << "consent file which is "
              << (new_value ? "on." : "off.");
  }
  VLOG(1) << "Metrics policy is being set to : " << new_value
          << "(use file : " << use_file << ")";
  // TODO(pastarmovj): Remove this once we don't need to regenerate the
  // consent file for the GUID anymore.
  OptionsUtil::ResolveMetricsReportingEnabled(new_value);
}

void DeviceSettingsProvider::ApplyRoamingSetting(bool new_value) {
  NetworkLibrary* cros = CrosLibrary::Get()->GetNetworkLibrary();
  const NetworkDevice* cellular = cros->FindCellularDevice();
  if (cellular) {
    bool device_value = cellular->data_roaming_allowed();
    if (!device_value && cros->IsCellularAlwaysInRoaming()) {
      // If operator requires roaming always enabled, ignore supplied value
      // and set data roaming allowed in true always.
      cros->SetCellularDataRoamingAllowed(true);
    } else if (device_value != new_value) {
      cros->SetCellularDataRoamingAllowed(new_value);
    }
  }
}

void DeviceSettingsProvider::ApplySideEffects(
    const em::ChromeDeviceSettingsProto& settings) {
  // First migrate metrics settings as needed.
  if (settings.has_metrics_enabled())
    ApplyMetricsSetting(false, settings.metrics_enabled().metrics_enabled());
  else
    ApplyMetricsSetting(true, false);

  // Next set the roaming setting as needed.
  ApplyRoamingSetting(
      settings.has_data_roaming_enabled() ?
          settings.data_roaming_enabled().data_roaming_enabled() :
          false);
}

bool DeviceSettingsProvider::MitigateMissingPolicy() {
  // First check if the device has been owned already and if not exit
  // immediately.
  if (g_browser_process->browser_policy_connector()->GetDeviceMode() !=
          policy::DEVICE_MODE_CONSUMER) {
    return false;
  }

  // If we are here the policy file were corrupted or missing. This can happen
  // because we are migrating Pre R11 device to the new secure policies or there
  // was an attempt to circumvent policy system. In this case we should populate
  // the policy cache with "safe-mode" defaults which should allow the owner to
  // log in but lock the device for anyone else until the policy blob has been
  // recreated by the session manager.
  LOG(ERROR) << "Corruption of the policy data has been detected."
             << "Switching to \"safe-mode\" policies until the owner logs in "
             << "to regenerate the policy data.";

  device_settings_.Clear();
  device_settings_.mutable_allow_new_users()->set_allow_new_users(true);
  device_settings_.mutable_guest_mode_enabled()->set_guest_mode_enabled(true);
  em::PolicyData empty_policy_data;
  UpdateValuesCache(empty_policy_data, device_settings_);
  values_cache_.SetBoolean(kPolicyMissingMitigationMode, true);
  trusted_status_ = TRUSTED;

  return true;
}

const base::Value* DeviceSettingsProvider::Get(const std::string& path) const {
  if (IsControlledSetting(path)) {
    const base::Value* value;
    if (values_cache_.GetValue(path, &value))
      return value;
  } else {
    NOTREACHED() << "Trying to get non cros setting.";
  }

  return NULL;
}

DeviceSettingsProvider::TrustedStatus
    DeviceSettingsProvider::PrepareTrustedValues(const base::Closure& cb) {
  TrustedStatus status = RequestTrustedEntity();
  if (status == TEMPORARILY_UNTRUSTED && !cb.is_null())
    callbacks_.push_back(cb);
  return status;
}

bool DeviceSettingsProvider::HandlesSetting(const std::string& path) const {
  return IsControlledSetting(path);
}

DeviceSettingsProvider::TrustedStatus
    DeviceSettingsProvider::RequestTrustedEntity() {
  if (ownership_status_ == DeviceSettingsService::OWNERSHIP_NONE)
    return TRUSTED;
  return trusted_status_;
}

void DeviceSettingsProvider::UpdateAndProceedStoring() {
  // Re-sync the cache from the service.
  UpdateFromService();

  // Trigger the next change if necessary.
  if (trusted_status_ == TRUSTED &&
      !store_callback_factory_.HasWeakPtrs() &&
      !pending_changes_.empty()) {
    SetInPolicy();
  }
}

bool DeviceSettingsProvider::UpdateFromService() {
  bool settings_loaded = false;
  switch (device_settings_service_->status()) {
    case DeviceSettingsService::STORE_SUCCESS: {
      const em::PolicyData* policy_data =
          device_settings_service_->policy_data();
      const em::ChromeDeviceSettingsProto* device_settings =
          device_settings_service_->device_settings();
      if (policy_data && device_settings) {
        UpdateValuesCache(*policy_data, *device_settings);
        device_settings_ = *device_settings;
        trusted_status_ = TRUSTED;

        // TODO(pastarmovj): Make those side effects responsibility of the
        // respective subsystems.
        ApplySideEffects(*device_settings);

        settings_loaded = true;
      } else {
        // Initial policy load is still pending.
        trusted_status_ = TEMPORARILY_UNTRUSTED;
      }
      break;
    }
    case DeviceSettingsService::STORE_NO_POLICY:
      if (MitigateMissingPolicy())
        break;
      // fall through.
    case DeviceSettingsService::STORE_KEY_UNAVAILABLE:
      VLOG(1) << "No policies present yet, will use the temp storage.";
      trusted_status_ = PERMANENTLY_UNTRUSTED;
      break;
    case DeviceSettingsService::STORE_POLICY_ERROR:
    case DeviceSettingsService::STORE_VALIDATION_ERROR:
    case DeviceSettingsService::STORE_INVALID_POLICY:
    case DeviceSettingsService::STORE_OPERATION_FAILED:
      LOG(ERROR) << "Failed to retrieve cros policies. Reason: "
                 << device_settings_service_->status();
      trusted_status_ = PERMANENTLY_UNTRUSTED;
      break;
  }

  // Notify the observers we are done.
  std::vector<base::Closure> callbacks;
  callbacks.swap(callbacks_);
  for (size_t i = 0; i < callbacks.size(); ++i)
    callbacks[i].Run();

  return settings_loaded;
}

void DeviceSettingsProvider::StoreDeviceSettings() {
  // Mute all previous callbacks to guarantee the |pending_changes_| queue is
  // processed serially.
  store_callback_factory_.InvalidateWeakPtrs();

  device_settings_service_->SignAndStore(
      scoped_ptr<em::ChromeDeviceSettingsProto>(
          new em::ChromeDeviceSettingsProto(device_settings_)),
      base::Bind(&DeviceSettingsProvider::UpdateAndProceedStoring,
                 store_callback_factory_.GetWeakPtr()));
}

void DeviceSettingsProvider::AttemptMigration() {
  if (device_settings_service_->HasPrivateOwnerKey()) {
    PrefValueMap::const_iterator i;
    for (i = migration_values_.begin(); i != migration_values_.end(); ++i)
      DoSet(i->first, *i->second);
    migration_values_.Clear();
  }
}

}  // namespace chromeos