// Copyright 2013 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 "chromeos/network/policy_util.h"

#include "base/logging.h"
#include "base/values.h"
#include "chromeos/network/network_profile.h"
#include "chromeos/network/network_ui_data.h"
#include "chromeos/network/onc/onc_merger.h"
#include "chromeos/network/onc/onc_normalizer.h"
#include "chromeos/network/onc/onc_signature.h"
#include "chromeos/network/onc/onc_translator.h"
#include "chromeos/network/onc/onc_utils.h"
#include "chromeos/network/shill_property_util.h"
#include "components/onc/onc_constants.h"
#include "third_party/cros_system_api/dbus/service_constants.h"

namespace chromeos {

namespace policy_util {

namespace {

// This fake credential contains a random postfix which is extremly unlikely to
// be used by any user.
const char kFakeCredential[] = "FAKE_CREDENTIAL_VPaJDV9x";


// Removes all kFakeCredential values from sensitive fields (determined by
// onc::FieldIsCredential) of |onc_object|.
void RemoveFakeCredentials(
    const onc::OncValueSignature& signature,
    base::DictionaryValue* onc_object) {
  base::DictionaryValue::Iterator it(*onc_object);
  while (!it.IsAtEnd()) {
    base::Value* value = NULL;
    std::string field_name = it.key();
    // We need the non-const entry to remove nested values but DictionaryValue
    // has no non-const iterator.
    onc_object->GetWithoutPathExpansion(field_name, &value);
    // Advance before delete.
    it.Advance();

    // If |value| is a dictionary, recurse.
    base::DictionaryValue* nested_object = NULL;
    if (value->GetAsDictionary(&nested_object)) {
      const onc::OncFieldSignature* field_signature =
          onc::GetFieldSignature(signature, field_name);
      if (field_signature)
        RemoveFakeCredentials(*field_signature->value_signature, nested_object);
      else
        LOG(ERROR) << "ONC has unrecoginzed field: " << field_name;
      continue;
    }

    // If |value| is a string, check if it is a fake credential.
    std::string string_value;
    if (value->GetAsString(&string_value) &&
        onc::FieldIsCredential(signature, field_name)) {
      if (string_value == kFakeCredential) {
        // The value wasn't modified by the UI, thus we remove the field to keep
        // the existing value that is stored in Shill.
        onc_object->RemoveWithoutPathExpansion(field_name, NULL);
      }
      // Otherwise, the value is set and modified by the UI, thus we keep that
      // value to overwrite whatever is stored in Shill.
    }
  }
}

// Returns true if |policy| matches |actual_network|, which must be part of a
// ONC NetworkConfiguration. This should be the only such matching function
// within Chrome. Shill does such matching in several functions for network
// identification. For compatibility, we currently should stick to Shill's
// matching behavior.
bool IsPolicyMatching(const base::DictionaryValue& policy,
                      const base::DictionaryValue& actual_network) {
  std::string policy_type;
  policy.GetStringWithoutPathExpansion(::onc::network_config::kType,
                                       &policy_type);
  std::string actual_network_type;
  actual_network.GetStringWithoutPathExpansion(::onc::network_config::kType,
                                               &actual_network_type);
  if (policy_type != actual_network_type)
    return false;

  if (actual_network_type == ::onc::network_type::kEthernet) {
    const base::DictionaryValue* policy_ethernet = NULL;
    policy.GetDictionaryWithoutPathExpansion(::onc::network_config::kEthernet,
                                             &policy_ethernet);
    const base::DictionaryValue* actual_ethernet = NULL;
    actual_network.GetDictionaryWithoutPathExpansion(
        ::onc::network_config::kEthernet, &actual_ethernet);
    if (!policy_ethernet || !actual_ethernet)
      return false;

    std::string policy_auth;
    policy_ethernet->GetStringWithoutPathExpansion(
        ::onc::ethernet::kAuthentication, &policy_auth);
    std::string actual_auth;
    actual_ethernet->GetStringWithoutPathExpansion(
        ::onc::ethernet::kAuthentication, &actual_auth);
    return policy_auth == actual_auth;
  } else if (actual_network_type == ::onc::network_type::kWiFi) {
    const base::DictionaryValue* policy_wifi = NULL;
    policy.GetDictionaryWithoutPathExpansion(::onc::network_config::kWiFi,
                                             &policy_wifi);
    const base::DictionaryValue* actual_wifi = NULL;
    actual_network.GetDictionaryWithoutPathExpansion(
        ::onc::network_config::kWiFi,
        &actual_wifi);
    if (!policy_wifi || !actual_wifi)
      return false;

    std::string policy_ssid;
    policy_wifi->GetStringWithoutPathExpansion(::onc::wifi::kSSID,
                                               &policy_ssid);
    std::string actual_ssid;
    actual_wifi->GetStringWithoutPathExpansion(::onc::wifi::kSSID,
                                               &actual_ssid);
    return (policy_ssid == actual_ssid);
  }
  return false;
}

}  // namespace

scoped_ptr<base::DictionaryValue> CreateShillConfiguration(
    const NetworkProfile& profile,
    const std::string& guid,
    const base::DictionaryValue* policy,
    const base::DictionaryValue* settings) {
  scoped_ptr<base::DictionaryValue> effective;
  ::onc::ONCSource onc_source = ::onc::ONC_SOURCE_NONE;
  if (policy) {
    if (profile.type() == NetworkProfile::TYPE_SHARED) {
      effective = onc::MergeSettingsAndPoliciesToEffective(
          NULL,  // no user policy
          policy,  // device policy
          NULL,  // no user settings
          settings);  // shared settings
      onc_source = ::onc::ONC_SOURCE_DEVICE_POLICY;
    } else if (profile.type() == NetworkProfile::TYPE_USER) {
      effective = onc::MergeSettingsAndPoliciesToEffective(
          policy,  // user policy
          NULL,  // no device policy
          settings,  // user settings
          NULL);  // no shared settings
      onc_source = ::onc::ONC_SOURCE_USER_POLICY;
    } else {
      NOTREACHED();
    }
  } else if (settings) {
    effective.reset(settings->DeepCopy());
    // TODO(pneubeck): change to source ONC_SOURCE_USER
    onc_source = ::onc::ONC_SOURCE_NONE;
  } else {
    NOTREACHED();
    onc_source = ::onc::ONC_SOURCE_NONE;
  }

  RemoveFakeCredentials(onc::kNetworkConfigurationSignature,
                        effective.get());

  effective->SetStringWithoutPathExpansion(::onc::network_config::kGUID, guid);

  // Remove irrelevant fields.
  onc::Normalizer normalizer(true /* remove recommended fields */);
  effective = normalizer.NormalizeObject(&onc::kNetworkConfigurationSignature,
                                         *effective);

  scoped_ptr<base::DictionaryValue> shill_dictionary(
      onc::TranslateONCObjectToShill(&onc::kNetworkConfigurationSignature,
                                     *effective));

  shill_dictionary->SetStringWithoutPathExpansion(shill::kProfileProperty,
                                                  profile.path);

  scoped_ptr<NetworkUIData> ui_data;
  if (policy)
    ui_data = NetworkUIData::CreateFromONC(onc_source, *policy);
  else
    ui_data.reset(new NetworkUIData());

  if (settings) {
    // Shill doesn't know that sensitive data is contained in the UIData
    // property and might write it into logs or other insecure places. Thus, we
    // have to remove or mask credentials.
    //
    // Shill's GetProperties doesn't return credentials. Masking credentials
    // instead of just removing them, allows remembering if a credential is set
    // or not.
    scoped_ptr<base::DictionaryValue> sanitized_settings(
        onc::MaskCredentialsInOncObject(onc::kNetworkConfigurationSignature,
                                        *settings,
                                        kFakeCredential));
    ui_data->set_user_settings(sanitized_settings.Pass());
  }

  shill_property_util::SetUIData(*ui_data, shill_dictionary.get());

  VLOG(2) << "Created Shill properties: " << *shill_dictionary;

  return shill_dictionary.Pass();
}

const base::DictionaryValue* FindMatchingPolicy(
    const GuidToPolicyMap& policies,
    const base::DictionaryValue& actual_network) {
  for (GuidToPolicyMap::const_iterator it = policies.begin();
       it != policies.end(); ++it) {
    if (IsPolicyMatching(*it->second, actual_network))
      return it->second;
  }
  return NULL;
}

}  // namespace policy_util

}  // namespace chromeos