// 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.

#include "components/user_manager/user_manager_base.h"

#include <stddef.h>
#include <set>
#include <utility>

#include "base/bind.h"
#include "base/bind_helpers.h"
#include "base/command_line.h"
#include "base/compiler_specific.h"
#include "base/format_macros.h"
#include "base/location.h"
#include "base/logging.h"
#include "base/macros.h"
#include "base/memory/ptr_util.h"
#include "base/metrics/histogram.h"
#include "base/strings/string_util.h"
#include "base/strings/stringprintf.h"
#include "base/strings/utf_string_conversions.h"
#include "base/task_runner.h"
#include "base/values.h"
#include "components/prefs/pref_registry_simple.h"
#include "components/prefs/pref_service.h"
#include "components/prefs/scoped_user_pref_update.h"
#include "components/user_manager/known_user.h"
#include "components/user_manager/remove_user_delegate.h"
#include "components/user_manager/user_type.h"
#include "google_apis/gaia/gaia_auth_util.h"

namespace user_manager {
namespace {

// A vector pref of the the regular users known on this device, arranged in LRU
// order.
const char kRegularUsers[] = "LoggedInUsers";

// A dictionary that maps user IDs to the displayed name.
const char kUserDisplayName[] = "UserDisplayName";

// A dictionary that maps user IDs to the user's given name.
const char kUserGivenName[] = "UserGivenName";

// A dictionary that maps user IDs to the displayed (non-canonical) emails.
const char kUserDisplayEmail[] = "UserDisplayEmail";

// A dictionary that maps user IDs to OAuth token presence flag.
const char kUserOAuthTokenStatus[] = "OAuthTokenStatus";

// A dictionary that maps user IDs to a flag indicating whether online
// authentication against GAIA should be enforced during the next sign-in.
const char kUserForceOnlineSignin[] = "UserForceOnlineSignin";

// A dictionary that maps user ID to the user type.
const char kUserType[] = "UserType";

// A string pref containing the ID of the last user who logged in if it was
// a user with gaia account (regular) or an empty string if it was another type
// of user (guest, kiosk, public account, etc.).
const char kLastLoggedInGaiaUser[] = "LastLoggedInRegularUser";

// A string pref containing the ID of the last active user.
// In case of browser crash, this pref will be used to set active user after
// session restore.
const char kLastActiveUser[] = "LastActiveUser";

// Upper bound for a histogram metric reporting the amount of time between
// one regular user logging out and a different regular user logging in.
const int kLogoutToLoginDelayMaxSec = 1800;

}  // namespace

// static
void UserManagerBase::RegisterPrefs(PrefRegistrySimple* registry) {
  registry->RegisterListPref(kRegularUsers);
  registry->RegisterStringPref(kLastLoggedInGaiaUser, std::string());
  registry->RegisterDictionaryPref(kUserDisplayName);
  registry->RegisterDictionaryPref(kUserGivenName);
  registry->RegisterDictionaryPref(kUserDisplayEmail);
  registry->RegisterDictionaryPref(kUserOAuthTokenStatus);
  registry->RegisterDictionaryPref(kUserForceOnlineSignin);
  registry->RegisterDictionaryPref(kUserType);
  registry->RegisterStringPref(kLastActiveUser, std::string());

  known_user::RegisterPrefs(registry);
}

UserManagerBase::UserManagerBase(scoped_refptr<base::TaskRunner> task_runner)
    : task_runner_(task_runner), weak_factory_(this) {}

UserManagerBase::~UserManagerBase() {
  // Can't use STLDeleteElements because of the private destructor of User.
  for (UserList::iterator it = users_.begin(); it != users_.end();
       it = users_.erase(it)) {
    DeleteUser(*it);
  }
  // These are pointers to the same User instances that were in users_ list.
  logged_in_users_.clear();
  lru_logged_in_users_.clear();

  DeleteUser(active_user_);
}

void UserManagerBase::Shutdown() {
  DCHECK(task_runner_->RunsTasksOnCurrentThread());
}

const UserList& UserManagerBase::GetUsers() const {
  const_cast<UserManagerBase*>(this)->EnsureUsersLoaded();
  return users_;
}

const UserList& UserManagerBase::GetLoggedInUsers() const {
  return logged_in_users_;
}

const UserList& UserManagerBase::GetLRULoggedInUsers() const {
  return lru_logged_in_users_;
}

const AccountId& UserManagerBase::GetOwnerAccountId() const {
  return owner_account_id_;
}

void UserManagerBase::UserLoggedIn(const AccountId& account_id,
                                   const std::string& username_hash,
                                   bool browser_restart) {
  DCHECK(task_runner_->RunsTasksOnCurrentThread());

  if (!last_session_active_account_id_initialized_) {
    last_session_active_account_id_ =
        AccountId::FromUserEmail(GetLocalState()->GetString(kLastActiveUser));
    last_session_active_account_id_initialized_ = true;
  }

  User* user = FindUserInListAndModify(account_id);
  if (active_user_ && user) {
    user->set_is_logged_in(true);
    user->set_username_hash(username_hash);
    logged_in_users_.push_back(user);
    lru_logged_in_users_.push_back(user);

    // Reset the new user flag if the user already exists.
    SetIsCurrentUserNew(false);
    NotifyUserAddedToSession(user, true /* user switch pending */);

    return;
  }

  if (IsGuestAccountId(account_id)) {
    GuestUserLoggedIn();
  } else if (IsDemoApp(account_id)) {
    DemoAccountLoggedIn();
  } else {
    EnsureUsersLoaded();

    if (user && user->GetType() == USER_TYPE_PUBLIC_ACCOUNT) {
      PublicAccountUserLoggedIn(user);
    } else if (user && user->GetType() == USER_TYPE_KIOSK_APP) {
      KioskAppLoggedIn(user);
    } else if (user && user->GetType() == USER_TYPE_ARC_KIOSK_APP) {
      ArcKioskAppLoggedIn(user);
    } else if ((user && user->GetType() == USER_TYPE_SUPERVISED) ||
               (!user && IsSupervisedAccountId(account_id))) {
      SupervisedUserLoggedIn(account_id);
    } else if (browser_restart &&
               IsDeviceLocalAccountMarkedForRemoval(account_id)) {
      PublicAccountUserLoggedIn(User::CreatePublicAccountUser(account_id));
    } else if (account_id != GetOwnerAccountId() && !user &&
               (AreEphemeralUsersEnabled() || browser_restart)) {
      RegularUserLoggedInAsEphemeral(account_id);
    } else {
      RegularUserLoggedIn(account_id);
    }
  }

  DCHECK(active_user_);
  active_user_->set_is_logged_in(true);
  active_user_->set_is_active(true);
  active_user_->set_username_hash(username_hash);

  // Place user who just signed in to the top of the logged in users.
  logged_in_users_.insert(logged_in_users_.begin(), active_user_);
  SetLRUUser(active_user_);

  if (!primary_user_) {
    primary_user_ = active_user_;
    if (primary_user_->HasGaiaAccount())
      SendGaiaUserLoginMetrics(account_id);
  }

  UMA_HISTOGRAM_ENUMERATION(
      "UserManager.LoginUserType", active_user_->GetType(), NUM_USER_TYPES);

  GetLocalState()->SetString(
      kLastLoggedInGaiaUser,
      active_user_->HasGaiaAccount() ? account_id.GetUserEmail() : "");

  NotifyOnLogin();
  PerformPostUserLoggedInActions(browser_restart);
}

void UserManagerBase::SwitchActiveUser(const AccountId& account_id) {
  User* user = FindUserAndModify(account_id);
  if (!user) {
    NOTREACHED() << "Switching to a non-existing user";
    return;
  }
  if (user == active_user_) {
    NOTREACHED() << "Switching to a user who is already active";
    return;
  }
  if (!user->is_logged_in()) {
    NOTREACHED() << "Switching to a user that is not logged in";
    return;
  }
  if (!user->HasGaiaAccount()) {
    NOTREACHED() <<
        "Switching to a user without gaia account (non-regular one)";
    return;
  }
  if (user->username_hash().empty()) {
    NOTREACHED() << "Switching to a user that doesn't have username_hash set";
    return;
  }

  DCHECK(active_user_);
  active_user_->set_is_active(false);
  user->set_is_active(true);
  active_user_ = user;

  // Move the user to the front.
  SetLRUUser(active_user_);

  NotifyActiveUserHashChanged(active_user_->username_hash());
  NotifyActiveUserChanged(active_user_);
}

void UserManagerBase::SwitchToLastActiveUser() {
  if (!last_session_active_account_id_.is_valid())
    return;

  if (AccountId::FromUserEmail(
          GetActiveUser()->GetAccountId().GetUserEmail()) !=
      last_session_active_account_id_)
    SwitchActiveUser(last_session_active_account_id_);

  // Make sure that this function gets run only once.
  last_session_active_account_id_.clear();
}

void UserManagerBase::OnSessionStarted() {
  DCHECK(task_runner_->RunsTasksOnCurrentThread());

  CallUpdateLoginState();
  GetLocalState()->CommitPendingWrite();
}

void UserManagerBase::RemoveUser(const AccountId& account_id,
                                 RemoveUserDelegate* delegate) {
  DCHECK(task_runner_->RunsTasksOnCurrentThread());

  if (!CanUserBeRemoved(FindUser(account_id)))
    return;

  RemoveUserInternal(account_id, delegate);
}

void UserManagerBase::RemoveUserInternal(const AccountId& account_id,
                                         RemoveUserDelegate* delegate) {
  RemoveNonOwnerUserInternal(account_id, delegate);
}

void UserManagerBase::RemoveNonOwnerUserInternal(const AccountId& account_id,
                                                 RemoveUserDelegate* delegate) {
  if (delegate)
    delegate->OnBeforeUserRemoved(account_id);
  RemoveUserFromList(account_id);
  AsyncRemoveCryptohome(account_id);

  if (delegate)
    delegate->OnUserRemoved(account_id);
}

void UserManagerBase::RemoveUserFromList(const AccountId& account_id) {
  DCHECK(task_runner_->RunsTasksOnCurrentThread());
  RemoveNonCryptohomeData(account_id);
  if (user_loading_stage_ == STAGE_LOADED) {
    DeleteUser(RemoveRegularOrSupervisedUserFromList(account_id));
  } else if (user_loading_stage_ == STAGE_LOADING) {
    DCHECK(IsSupervisedAccountId(account_id) ||
           HasPendingBootstrap(account_id));
    // Special case, removing partially-constructed supervised user or
    // boostrapping user during user list loading.
    ListPrefUpdate users_update(GetLocalState(), kRegularUsers);
    users_update->Remove(base::StringValue(account_id.GetUserEmail()), nullptr);
    OnUserRemoved(account_id);
  } else {
    NOTREACHED() << "Users are not loaded yet.";
    return;
  }

  // Make sure that new data is persisted to Local State.
  GetLocalState()->CommitPendingWrite();
}

bool UserManagerBase::IsKnownUser(const AccountId& account_id) const {
  return FindUser(account_id) != nullptr;
}

const User* UserManagerBase::FindUser(const AccountId& account_id) const {
  DCHECK(task_runner_->RunsTasksOnCurrentThread());
  if (active_user_ && active_user_->GetAccountId() == account_id)
    return active_user_;
  return FindUserInList(account_id);
}

User* UserManagerBase::FindUserAndModify(const AccountId& account_id) {
  DCHECK(task_runner_->RunsTasksOnCurrentThread());
  if (active_user_ && active_user_->GetAccountId() == account_id)
    return active_user_;
  return FindUserInListAndModify(account_id);
}

const User* UserManagerBase::GetActiveUser() const {
  DCHECK(task_runner_->RunsTasksOnCurrentThread());
  return active_user_;
}

User* UserManagerBase::GetActiveUser() {
  DCHECK(task_runner_->RunsTasksOnCurrentThread());
  return active_user_;
}

const User* UserManagerBase::GetPrimaryUser() const {
  DCHECK(task_runner_->RunsTasksOnCurrentThread());
  return primary_user_;
}

void UserManagerBase::SaveUserOAuthStatus(
    const AccountId& account_id,
    User::OAuthTokenStatus oauth_token_status) {
  DCHECK(task_runner_->RunsTasksOnCurrentThread());

  DVLOG(1) << "Saving user OAuth token status in Local State";
  User* user = FindUserAndModify(account_id);
  if (user)
    user->set_oauth_token_status(oauth_token_status);

  // Do not update local state if data stored or cached outside the user's
  // cryptohome is to be treated as ephemeral.
  if (IsUserNonCryptohomeDataEphemeral(account_id))
    return;

  {
    DictionaryPrefUpdate oauth_status_update(GetLocalState(),
                                             kUserOAuthTokenStatus);
    oauth_status_update->SetWithoutPathExpansion(
        account_id.GetUserEmail(),
        new base::FundamentalValue(static_cast<int>(oauth_token_status)));
  }
  GetLocalState()->CommitPendingWrite();
}

void UserManagerBase::SaveForceOnlineSignin(const AccountId& account_id,
                                            bool force_online_signin) {
  DCHECK(task_runner_->RunsTasksOnCurrentThread());

  // Do not update local state if data stored or cached outside the user's
  // cryptohome is to be treated as ephemeral.
  if (IsUserNonCryptohomeDataEphemeral(account_id))
    return;

  {
    DictionaryPrefUpdate force_online_update(GetLocalState(),
                                             kUserForceOnlineSignin);
    force_online_update->SetBooleanWithoutPathExpansion(
        account_id.GetUserEmail(), force_online_signin);
  }
  GetLocalState()->CommitPendingWrite();
}

void UserManagerBase::SaveUserDisplayName(const AccountId& account_id,
                                          const base::string16& display_name) {
  DCHECK(task_runner_->RunsTasksOnCurrentThread());

  if (User* user = FindUserAndModify(account_id)) {
    user->set_display_name(display_name);

    // Do not update local state if data stored or cached outside the user's
    // cryptohome is to be treated as ephemeral.
    if (!IsUserNonCryptohomeDataEphemeral(account_id)) {
      DictionaryPrefUpdate display_name_update(GetLocalState(),
                                               kUserDisplayName);
      display_name_update->SetWithoutPathExpansion(
          account_id.GetUserEmail(), new base::StringValue(display_name));
    }
  }
}

base::string16 UserManagerBase::GetUserDisplayName(
    const AccountId& account_id) const {
  const User* user = FindUser(account_id);
  return user ? user->display_name() : base::string16();
}

void UserManagerBase::SaveUserDisplayEmail(const AccountId& account_id,
                                           const std::string& display_email) {
  DCHECK(task_runner_->RunsTasksOnCurrentThread());

  User* user = FindUserAndModify(account_id);
  if (!user) {
    LOG(ERROR) << "User not found: " << account_id.GetUserEmail();
    return;  // Ignore if there is no such user.
  }

  user->set_display_email(display_email);

  // Do not update local state if data stored or cached outside the user's
  // cryptohome is to be treated as ephemeral.
  if (IsUserNonCryptohomeDataEphemeral(account_id))
    return;

  DictionaryPrefUpdate display_email_update(GetLocalState(), kUserDisplayEmail);
  display_email_update->SetWithoutPathExpansion(
      account_id.GetUserEmail(), new base::StringValue(display_email));
}

std::string UserManagerBase::GetUserDisplayEmail(
    const AccountId& account_id) const {
  const User* user = FindUser(account_id);
  return user ? user->display_email() : account_id.GetUserEmail();
}

void UserManagerBase::SaveUserType(const AccountId& account_id,
                                   const UserType& user_type) {
  DCHECK(task_runner_->RunsTasksOnCurrentThread());

  User* user = FindUserAndModify(account_id);
  if (!user) {
    LOG(ERROR) << "User not found: " << account_id.GetUserEmail();
    return;  // Ignore if there is no such user.
  }

  // Do not update local state if data stored or cached outside the user's
  // cryptohome is to be treated as ephemeral.
  if (IsUserNonCryptohomeDataEphemeral(account_id))
    return;

  DictionaryPrefUpdate user_type_update(GetLocalState(), kUserType);
  user_type_update->SetWithoutPathExpansion(
      account_id.GetUserEmail(),
      new base::FundamentalValue(static_cast<int>(user_type)));
  GetLocalState()->CommitPendingWrite();
}

void UserManagerBase::UpdateUserAccountData(
    const AccountId& account_id,
    const UserAccountData& account_data) {
  DCHECK(task_runner_->RunsTasksOnCurrentThread());

  SaveUserDisplayName(account_id, account_data.display_name());

  if (User* user = FindUserAndModify(account_id)) {
    base::string16 given_name = account_data.given_name();
    user->set_given_name(given_name);
    if (!IsUserNonCryptohomeDataEphemeral(account_id)) {
      DictionaryPrefUpdate given_name_update(GetLocalState(), kUserGivenName);
      given_name_update->SetWithoutPathExpansion(
          account_id.GetUserEmail(), new base::StringValue(given_name));
    }
  }

  UpdateUserAccountLocale(account_id, account_data.locale());
}

void UserManagerBase::ParseUserList(const base::ListValue& users_list,
                                    const std::set<AccountId>& existing_users,
                                    std::vector<AccountId>* users_vector,
                                    std::set<AccountId>* users_set) {
  users_vector->clear();
  users_set->clear();
  for (size_t i = 0; i < users_list.GetSize(); ++i) {
    std::string email;
    if (!users_list.GetString(i, &email) || email.empty()) {
      LOG(ERROR) << "Corrupt entry in user list at index " << i << ".";
      continue;
    }

    const AccountId account_id = known_user::GetAccountId(email, std::string());

    if (existing_users.find(account_id) != existing_users.end() ||
        !users_set->insert(account_id).second) {
      LOG(ERROR) << "Duplicate user: " << email;
      continue;
    }
    users_vector->push_back(account_id);
  }
}

bool UserManagerBase::IsCurrentUserOwner() const {
  DCHECK(task_runner_->RunsTasksOnCurrentThread());
  base::AutoLock lk(is_current_user_owner_lock_);
  return is_current_user_owner_;
}

void UserManagerBase::SetCurrentUserIsOwner(bool is_current_user_owner) {
  DCHECK(task_runner_->RunsTasksOnCurrentThread());
  {
    base::AutoLock lk(is_current_user_owner_lock_);
    is_current_user_owner_ = is_current_user_owner;
  }
  CallUpdateLoginState();
}

bool UserManagerBase::IsCurrentUserNew() const {
  DCHECK(task_runner_->RunsTasksOnCurrentThread());
  return is_current_user_new_;
}

bool UserManagerBase::IsCurrentUserNonCryptohomeDataEphemeral() const {
  DCHECK(task_runner_->RunsTasksOnCurrentThread());
  return IsUserLoggedIn() &&
         IsUserNonCryptohomeDataEphemeral(GetActiveUser()->GetAccountId());
}

bool UserManagerBase::IsCurrentUserCryptohomeDataEphemeral() const {
  DCHECK(task_runner_->RunsTasksOnCurrentThread());
  return IsUserLoggedIn() &&
         IsUserCryptohomeDataEphemeral(GetActiveUser()->GetAccountId());
}

bool UserManagerBase::CanCurrentUserLock() const {
  DCHECK(task_runner_->RunsTasksOnCurrentThread());
  return IsUserLoggedIn() && active_user_->can_lock();
}

bool UserManagerBase::IsUserLoggedIn() const {
  DCHECK(task_runner_->RunsTasksOnCurrentThread());
  return active_user_;
}

bool UserManagerBase::IsLoggedInAsUserWithGaiaAccount() const {
  DCHECK(task_runner_->RunsTasksOnCurrentThread());
  return IsUserLoggedIn() && active_user_->HasGaiaAccount();
}

bool UserManagerBase::IsLoggedInAsChildUser() const {
  DCHECK(task_runner_->RunsTasksOnCurrentThread());
  return IsUserLoggedIn() && active_user_->GetType() == USER_TYPE_CHILD;
}

bool UserManagerBase::IsLoggedInAsPublicAccount() const {
  DCHECK(task_runner_->RunsTasksOnCurrentThread());
  return IsUserLoggedIn() &&
         active_user_->GetType() == USER_TYPE_PUBLIC_ACCOUNT;
}

bool UserManagerBase::IsLoggedInAsGuest() const {
  DCHECK(task_runner_->RunsTasksOnCurrentThread());
  return IsUserLoggedIn() && active_user_->GetType() == USER_TYPE_GUEST;
}

bool UserManagerBase::IsLoggedInAsSupervisedUser() const {
  DCHECK(task_runner_->RunsTasksOnCurrentThread());
  return IsUserLoggedIn() && active_user_->GetType() == USER_TYPE_SUPERVISED;
}

bool UserManagerBase::IsLoggedInAsKioskApp() const {
  DCHECK(task_runner_->RunsTasksOnCurrentThread());
  return IsUserLoggedIn() && active_user_->GetType() == USER_TYPE_KIOSK_APP;
}

bool UserManagerBase::IsLoggedInAsArcKioskApp() const {
  DCHECK(task_runner_->RunsTasksOnCurrentThread());
  return IsUserLoggedIn() && active_user_->GetType() == USER_TYPE_ARC_KIOSK_APP;
}

bool UserManagerBase::IsLoggedInAsStub() const {
  DCHECK(task_runner_->RunsTasksOnCurrentThread());
  return IsUserLoggedIn() && IsStubAccountId(active_user_->GetAccountId());
}

bool UserManagerBase::IsUserNonCryptohomeDataEphemeral(
    const AccountId& account_id) const {
  // Data belonging to the guest and stub users is always ephemeral.
  if (IsGuestAccountId(account_id) || IsStubAccountId(account_id))
    return true;

  // Data belonging to the owner, anyone found on the user list and obsolete
  // device local accounts whose data has not been removed yet is not ephemeral.
  if (account_id == GetOwnerAccountId() || UserExistsInList(account_id) ||
      IsDeviceLocalAccountMarkedForRemoval(account_id)) {
    return false;
  }

  // Data belonging to the currently logged-in user is ephemeral when:
  // a) The user logged into a regular gaia account while the ephemeral users
  //    policy was enabled.
  //    - or -
  // b) The user logged into any other account type.
  if (IsUserLoggedIn() && (account_id == GetActiveUser()->GetAccountId()) &&
      (is_current_user_ephemeral_regular_user_ ||
       !IsLoggedInAsUserWithGaiaAccount())) {
    return true;
  }

  // Data belonging to any other user is ephemeral when:
  // a) Going through the regular login flow and the ephemeral users policy is
  //    enabled.
  //    - or -
  // b) The browser is restarting after a crash.
  return AreEphemeralUsersEnabled() || HasBrowserRestarted();
}

bool UserManagerBase::IsUserCryptohomeDataEphemeral(
    const AccountId& account_id) const {
  // Don't consider stub users data as ephemeral.
  if (IsStubAccountId(account_id))
    return false;

  // Data belonging to the guest and demo users is always ephemeral.
  if (IsGuestAccountId(account_id) || IsDemoApp(account_id))
    return true;

  // Data belonging to the public accounts is always ephemeral.
  const User* user = FindUser(account_id);
  if (user && user->GetType() == USER_TYPE_PUBLIC_ACCOUNT)
    return true;

  // Ephemeral users.
  if (AreEphemeralUsersEnabled() && user &&
      user->GetType() == USER_TYPE_REGULAR &&
      FindUserInList(account_id) == nullptr) {
    return true;
  }

  return false;
}

void UserManagerBase::AddObserver(UserManager::Observer* obs) {
  DCHECK(task_runner_->RunsTasksOnCurrentThread());
  observer_list_.AddObserver(obs);
}

void UserManagerBase::RemoveObserver(UserManager::Observer* obs) {
  DCHECK(task_runner_->RunsTasksOnCurrentThread());
  observer_list_.RemoveObserver(obs);
}

void UserManagerBase::AddSessionStateObserver(
    UserManager::UserSessionStateObserver* obs) {
  DCHECK(task_runner_->RunsTasksOnCurrentThread());
  session_state_observer_list_.AddObserver(obs);
}

void UserManagerBase::RemoveSessionStateObserver(
    UserManager::UserSessionStateObserver* obs) {
  DCHECK(task_runner_->RunsTasksOnCurrentThread());
  session_state_observer_list_.RemoveObserver(obs);
}

void UserManagerBase::NotifyLocalStateChanged() {
  DCHECK(task_runner_->RunsTasksOnCurrentThread());
  for (auto& observer : observer_list_)
    observer.LocalStateChanged(this);
}

bool UserManagerBase::CanUserBeRemoved(const User* user) const {
  // Only regular and supervised users are allowed to be manually removed.
  if (!user || !(user->HasGaiaAccount() || user->IsSupervised()))
    return false;

  // Sanity check: we must not remove single user unless it's an enterprise
  // device. This check may seem redundant at a first sight because
  // this single user must be an owner and we perform special check later
  // in order not to remove an owner. However due to non-instant nature of
  // ownership assignment this later check may sometimes fail.
  // See http://crosbug.com/12723
  if (users_.size() < 2 && !IsEnterpriseManaged())
    return false;

  // Sanity check: do not allow any of the the logged in users to be removed.
  for (UserList::const_iterator it = logged_in_users_.begin();
       it != logged_in_users_.end();
       ++it) {
    if ((*it)->GetAccountId() == user->GetAccountId())
      return false;
  }

  return true;
}

bool UserManagerBase::GetEphemeralUsersEnabled() const {
  return ephemeral_users_enabled_;
}

void UserManagerBase::SetEphemeralUsersEnabled(bool enabled) {
  ephemeral_users_enabled_ = enabled;
}

void UserManagerBase::SetIsCurrentUserNew(bool is_new) {
  is_current_user_new_ = is_new;
}

bool UserManagerBase::HasPendingBootstrap(const AccountId& account_id) const {
  return false;
}

void UserManagerBase::SetOwnerId(const AccountId& owner_account_id) {
  owner_account_id_ = owner_account_id;
}

const AccountId& UserManagerBase::GetPendingUserSwitchID() const {
  return pending_user_switch_;
}

void UserManagerBase::SetPendingUserSwitchId(const AccountId& account_id) {
  pending_user_switch_ = account_id;
}

void UserManagerBase::EnsureUsersLoaded() {
  DCHECK(task_runner_->RunsTasksOnCurrentThread());
  if (!GetLocalState())
    return;

  if (user_loading_stage_ != STAGE_NOT_LOADED)
    return;
  user_loading_stage_ = STAGE_LOADING;

  PerformPreUserListLoadingActions();

  PrefService* local_state = GetLocalState();
  const base::ListValue* prefs_regular_users =
      local_state->GetList(kRegularUsers);

  const base::DictionaryValue* prefs_display_names =
      local_state->GetDictionary(kUserDisplayName);
  const base::DictionaryValue* prefs_given_names =
      local_state->GetDictionary(kUserGivenName);
  const base::DictionaryValue* prefs_display_emails =
      local_state->GetDictionary(kUserDisplayEmail);
  const base::DictionaryValue* prefs_user_types =
      local_state->GetDictionary(kUserType);

  // Load public sessions first.
  std::set<AccountId> device_local_accounts_set;
  LoadDeviceLocalAccounts(&device_local_accounts_set);

  // Load regular users and supervised users.
  std::vector<AccountId> regular_users;
  std::set<AccountId> regular_users_set;
  ParseUserList(*prefs_regular_users, device_local_accounts_set, &regular_users,
                &regular_users_set);
  for (std::vector<AccountId>::const_iterator it = regular_users.begin();
       it != regular_users.end(); ++it) {
    User* user = nullptr;
    if (IsSupervisedAccountId(*it)) {
      user = User::CreateSupervisedUser(*it);
    } else {
      user = User::CreateRegularUser(*it);
      int user_type;
      if (prefs_user_types->GetIntegerWithoutPathExpansion(it->GetUserEmail(),
                                                           &user_type) &&
          user_type == USER_TYPE_CHILD) {
        ChangeUserChildStatus(user, true /* is child */);
      }
    }
    const AccountId account_id = user->GetAccountId();
    user->set_oauth_token_status(LoadUserOAuthStatus(*it));
    user->set_force_online_signin(LoadForceOnlineSignin(*it));
    user->set_using_saml(known_user::IsUsingSAML(*it));
    users_.push_back(user);

    base::string16 display_name;
    if (prefs_display_names->GetStringWithoutPathExpansion(it->GetUserEmail(),
                                                           &display_name)) {
      user->set_display_name(display_name);
    }

    base::string16 given_name;
    if (prefs_given_names->GetStringWithoutPathExpansion(it->GetUserEmail(),
                                                         &given_name)) {
      user->set_given_name(given_name);
    }

    std::string display_email;
    if (prefs_display_emails->GetStringWithoutPathExpansion(it->GetUserEmail(),
                                                            &display_email)) {
      user->set_display_email(display_email);
    }
  }

  user_loading_stage_ = STAGE_LOADED;

  PerformPostUserListLoadingActions();
}

UserList& UserManagerBase::GetUsersAndModify() {
  EnsureUsersLoaded();
  return users_;
}

const User* UserManagerBase::FindUserInList(const AccountId& account_id) const {
  const UserList& users = GetUsers();
  for (UserList::const_iterator it = users.begin(); it != users.end(); ++it) {
    if ((*it)->GetAccountId() == account_id)
      return *it;
  }
  return nullptr;
}

bool UserManagerBase::UserExistsInList(const AccountId& account_id) const {
  const base::ListValue* user_list = GetLocalState()->GetList(kRegularUsers);
  for (size_t i = 0; i < user_list->GetSize(); ++i) {
    std::string email;
    if (user_list->GetString(i, &email) && (account_id.GetUserEmail() == email))
      return true;
  }
  return false;
}

User* UserManagerBase::FindUserInListAndModify(const AccountId& account_id) {
  UserList& users = GetUsersAndModify();
  for (UserList::iterator it = users.begin(); it != users.end(); ++it) {
    if ((*it)->GetAccountId() == account_id)
      return *it;
  }
  return nullptr;
}

void UserManagerBase::GuestUserLoggedIn() {
  DCHECK(task_runner_->RunsTasksOnCurrentThread());
  active_user_ = User::CreateGuestUser(GetGuestAccountId());
}

void UserManagerBase::AddUserRecord(User* user) {
  // Add the user to the front of the user list.
  ListPrefUpdate prefs_users_update(GetLocalState(), kRegularUsers);
  prefs_users_update->Insert(0, base::MakeUnique<base::StringValue>(
                                    user->GetAccountId().GetUserEmail()));
  users_.insert(users_.begin(), user);
}

void UserManagerBase::RegularUserLoggedIn(const AccountId& account_id) {
  // Remove the user from the user list.
  active_user_ = RemoveRegularOrSupervisedUserFromList(account_id);

  // If the user was not found on the user list, create a new user.
  SetIsCurrentUserNew(!active_user_);
  if (IsCurrentUserNew()) {
    active_user_ = User::CreateRegularUser(account_id);
    active_user_->set_oauth_token_status(LoadUserOAuthStatus(account_id));
    SaveUserDisplayName(active_user_->GetAccountId(),
                        base::UTF8ToUTF16(active_user_->GetAccountName(true)));
  }

  AddUserRecord(active_user_);

  // Make sure that new data is persisted to Local State.
  GetLocalState()->CommitPendingWrite();
}

void UserManagerBase::RegularUserLoggedInAsEphemeral(
    const AccountId& account_id) {
  DCHECK(task_runner_->RunsTasksOnCurrentThread());
  SetIsCurrentUserNew(true);
  is_current_user_ephemeral_regular_user_ = true;
  active_user_ = User::CreateRegularUser(account_id);
}

void UserManagerBase::NotifyOnLogin() {
  DCHECK(task_runner_->RunsTasksOnCurrentThread());

  NotifyActiveUserHashChanged(active_user_->username_hash());
  NotifyActiveUserChanged(active_user_);
  CallUpdateLoginState();
}

User::OAuthTokenStatus UserManagerBase::LoadUserOAuthStatus(
    const AccountId& account_id) const {
  DCHECK(task_runner_->RunsTasksOnCurrentThread());

  const base::DictionaryValue* prefs_oauth_status =
      GetLocalState()->GetDictionary(kUserOAuthTokenStatus);
  int oauth_token_status = User::OAUTH_TOKEN_STATUS_UNKNOWN;
  if (prefs_oauth_status &&
      prefs_oauth_status->GetIntegerWithoutPathExpansion(
          account_id.GetUserEmail(), &oauth_token_status)) {
    User::OAuthTokenStatus status =
        static_cast<User::OAuthTokenStatus>(oauth_token_status);
    HandleUserOAuthTokenStatusChange(account_id, status);

    return status;
  }
  return User::OAUTH_TOKEN_STATUS_UNKNOWN;
}

bool UserManagerBase::LoadForceOnlineSignin(const AccountId& account_id) const {
  DCHECK(task_runner_->RunsTasksOnCurrentThread());

  const base::DictionaryValue* prefs_force_online =
      GetLocalState()->GetDictionary(kUserForceOnlineSignin);
  bool force_online_signin = false;
  if (prefs_force_online) {
    prefs_force_online->GetBooleanWithoutPathExpansion(
        account_id.GetUserEmail(), &force_online_signin);
  }
  return force_online_signin;
}

void UserManagerBase::RemoveNonCryptohomeData(const AccountId& account_id) {
  PrefService* prefs = GetLocalState();
  DictionaryPrefUpdate prefs_display_name_update(prefs, kUserDisplayName);
  prefs_display_name_update->RemoveWithoutPathExpansion(
      account_id.GetUserEmail(), nullptr);

  DictionaryPrefUpdate prefs_given_name_update(prefs, kUserGivenName);
  prefs_given_name_update->RemoveWithoutPathExpansion(account_id.GetUserEmail(),
                                                      nullptr);

  DictionaryPrefUpdate prefs_display_email_update(prefs, kUserDisplayEmail);
  prefs_display_email_update->RemoveWithoutPathExpansion(
      account_id.GetUserEmail(), nullptr);

  DictionaryPrefUpdate prefs_oauth_update(prefs, kUserOAuthTokenStatus);
  prefs_oauth_update->RemoveWithoutPathExpansion(account_id.GetUserEmail(),
                                                 nullptr);

  DictionaryPrefUpdate prefs_force_online_update(prefs, kUserForceOnlineSignin);
  prefs_force_online_update->RemoveWithoutPathExpansion(
      account_id.GetUserEmail(), nullptr);

  known_user::RemovePrefs(account_id);

  const AccountId last_active_user =
      AccountId::FromUserEmail(GetLocalState()->GetString(kLastActiveUser));
  if (account_id == last_active_user)
    GetLocalState()->SetString(kLastActiveUser, std::string());
}

User* UserManagerBase::RemoveRegularOrSupervisedUserFromList(
    const AccountId& account_id) {
  ListPrefUpdate prefs_users_update(GetLocalState(), kRegularUsers);
  prefs_users_update->Clear();
  User* user = nullptr;
  for (UserList::iterator it = users_.begin(); it != users_.end();) {
    if ((*it)->GetAccountId() == account_id) {
      user = *it;
      it = users_.erase(it);
    } else {
      if ((*it)->HasGaiaAccount() || (*it)->IsSupervised()) {
        const std::string user_email = (*it)->GetAccountId().GetUserEmail();
        prefs_users_update->AppendString(user_email);
      }
      ++it;
    }
  }
  OnUserRemoved(account_id);
  return user;
}

void UserManagerBase::NotifyActiveUserChanged(const User* active_user) {
  DCHECK(task_runner_->RunsTasksOnCurrentThread());
  for (auto& observer : session_state_observer_list_)
    observer.ActiveUserChanged(active_user);
}

void UserManagerBase::NotifyUserAddedToSession(const User* added_user,
                                               bool user_switch_pending) {
  DCHECK(task_runner_->RunsTasksOnCurrentThread());
  for (auto& observer : session_state_observer_list_)
    observer.UserAddedToSession(added_user);
}

void UserManagerBase::NotifyActiveUserHashChanged(const std::string& hash) {
  DCHECK(task_runner_->RunsTasksOnCurrentThread());
  for (auto& observer : session_state_observer_list_)
    observer.ActiveUserHashChanged(hash);
}

void UserManagerBase::ChangeUserChildStatus(User* user, bool is_child) {
  DCHECK(task_runner_->RunsTasksOnCurrentThread());
  if (user->IsSupervised() == is_child)
    return;
  user->SetIsChild(is_child);
  SaveUserType(user->GetAccountId(), is_child
                                         ? user_manager::USER_TYPE_CHILD
                                         : user_manager::USER_TYPE_REGULAR);
  for (auto& observer : session_state_observer_list_)
    observer.UserChangedChildStatus(user);
}

void UserManagerBase::Initialize() {
  UserManager::Initialize();
  CallUpdateLoginState();
}

void UserManagerBase::CallUpdateLoginState() {
  UpdateLoginState(active_user_, primary_user_, is_current_user_owner_);
}

void UserManagerBase::SetLRUUser(User* user) {
  GetLocalState()->SetString(kLastActiveUser,
                             user->GetAccountId().GetUserEmail());
  GetLocalState()->CommitPendingWrite();

  UserList::iterator it =
      std::find(lru_logged_in_users_.begin(), lru_logged_in_users_.end(), user);
  if (it != lru_logged_in_users_.end())
    lru_logged_in_users_.erase(it);
  lru_logged_in_users_.insert(lru_logged_in_users_.begin(), user);
}

void UserManagerBase::SendGaiaUserLoginMetrics(const AccountId& account_id) {
  // If this isn't the first time Chrome was run after the system booted,
  // assume that Chrome was restarted because a previous session ended.
  if (IsFirstExecAfterBoot())
    return;

  const std::string last_email =
      GetLocalState()->GetString(kLastLoggedInGaiaUser);
  const base::TimeDelta time_to_login =
      base::TimeTicks::Now() - manager_creation_time_;
  if (!last_email.empty() &&
      account_id != AccountId::FromUserEmail(last_email) &&
      time_to_login.InSeconds() <= kLogoutToLoginDelayMaxSec) {
    UMA_HISTOGRAM_CUSTOM_COUNTS("UserManager.LogoutToLoginDelay",
                                time_to_login.InSeconds(), 1,
                                kLogoutToLoginDelayMaxSec, 50);
  }
}

void UserManagerBase::UpdateUserAccountLocale(const AccountId& account_id,
                                              const std::string& locale) {
  std::unique_ptr<std::string> resolved_locale(new std::string());
  if (!locale.empty() && locale != GetApplicationLocale()) {
    // base::Passed will nullptr out |resolved_locale|, so cache the underlying
    // ptr.
    std::string* raw_resolved_locale = resolved_locale.get();
    ScheduleResolveLocale(locale,
                          base::Bind(&UserManagerBase::DoUpdateAccountLocale,
                                     weak_factory_.GetWeakPtr(), account_id,
                                     base::Passed(&resolved_locale)),
                          raw_resolved_locale);
  } else {
    resolved_locale.reset(new std::string(locale));
    DoUpdateAccountLocale(account_id, std::move(resolved_locale));
  }
}

void UserManagerBase::DoUpdateAccountLocale(
    const AccountId& account_id,
    std::unique_ptr<std::string> resolved_locale) {
  User* user = FindUserAndModify(account_id);
  if (user && resolved_locale)
    user->SetAccountLocale(*resolved_locale);
}

void UserManagerBase::DeleteUser(User* user) {
  const bool is_active_user = (user == active_user_);
  delete user;
  if (is_active_user)
    active_user_ = nullptr;
}

}  // namespace user_manager