// Copyright 2017 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 "ash/shelf/login_shelf_view.h"

#include <memory>
#include <utility>

#include "ash/focus_cycler.h"
#include "ash/lock_screen_action/lock_screen_action_background_controller.h"
#include "ash/lock_screen_action/lock_screen_action_background_state.h"
#include "ash/login/login_screen_controller.h"
#include "ash/login/ui/lock_screen.h"
#include "ash/public/cpp/ash_constants.h"
#include "ash/public/cpp/login_constants.h"
#include "ash/public/interfaces/kiosk_app_info.mojom.h"
#include "ash/resources/vector_icons/vector_icons.h"
#include "ash/root_window_controller.h"
#include "ash/session/session_controller.h"
#include "ash/session/session_observer.h"
#include "ash/shelf/shelf.h"
#include "ash/shelf/shelf_constants.h"
#include "ash/shelf/shelf_widget.h"
#include "ash/shell.h"
#include "ash/shutdown_controller.h"
#include "ash/strings/grit/ash_strings.h"
#include "ash/system/status_area_widget.h"
#include "ash/system/status_area_widget_delegate.h"
#include "ash/system/tray/system_tray_notifier.h"
#include "ash/system/tray/tray_popup_utils.h"
#include "ash/tray_action/tray_action.h"
#include "ash/wm/lock_state_controller.h"
#include "base/metrics/user_metrics.h"
#include "chromeos/strings/grit/chromeos_strings.h"
#include "skia/ext/image_operations.h"
#include "ui/accessibility/ax_node_data.h"
#include "ui/base/l10n/l10n_util.h"
#include "ui/base/models/menu_model.h"
#include "ui/base/models/simple_menu_model.h"
#include "ui/gfx/canvas.h"
#include "ui/gfx/color_palette.h"
#include "ui/gfx/geometry/rect.h"
#include "ui/gfx/geometry/size.h"
#include "ui/gfx/image/image_skia_operations.h"
#include "ui/gfx/paint_vector_icon.h"
#include "ui/gfx/vector_icon_types.h"
#include "ui/views/accessibility/ax_aura_obj_cache.h"
#include "ui/views/animation/ink_drop_impl.h"
#include "ui/views/animation/ink_drop_mask.h"
#include "ui/views/controls/button/label_button.h"
#include "ui/views/controls/button/menu_button.h"
#include "ui/views/controls/button/menu_button_listener.h"
#include "ui/views/controls/menu/menu_runner.h"
#include "ui/views/controls/menu/menu_types.h"
#include "ui/views/focus/focus_search.h"
#include "ui/views/layout/box_layout.h"
#include "ui/views/view_properties.h"
#include "ui/views/widget/widget.h"

using session_manager::SessionState;

namespace ash {
namespace {

LoginMetricsRecorder::ShelfButtonClickTarget GetUserClickTarget(int button_id) {
  switch (button_id) {
    case LoginShelfView::kShutdown:
      return LoginMetricsRecorder::ShelfButtonClickTarget::kShutDownButton;
    case LoginShelfView::kRestart:
      return LoginMetricsRecorder::ShelfButtonClickTarget::kRestartButton;
    case LoginShelfView::kSignOut:
      return LoginMetricsRecorder::ShelfButtonClickTarget::kSignOutButton;
    case LoginShelfView::kCloseNote:
      return LoginMetricsRecorder::ShelfButtonClickTarget::kCloseNoteButton;
    case LoginShelfView::kBrowseAsGuest:
      return LoginMetricsRecorder::ShelfButtonClickTarget::kBrowseAsGuestButton;
    case LoginShelfView::kAddUser:
      return LoginMetricsRecorder::ShelfButtonClickTarget::kAddUserButton;
    case LoginShelfView::kCancel:
      return LoginMetricsRecorder::ShelfButtonClickTarget::kCancelButton;
    case LoginShelfView::kParentAccess:
      return LoginMetricsRecorder::ShelfButtonClickTarget::kParentAccessButton;
  }
  return LoginMetricsRecorder::ShelfButtonClickTarget::kTargetCount;
}

// The margins of the button contents.
constexpr int kButtonMarginTopDp = 18;
constexpr int kButtonMarginLeftDp = 18;
constexpr int kButtonMarginBottomDp = 18;
constexpr int kButtonMarginRightDp = 16;

// The margins of the button background.
constexpr gfx::Insets kButtonBackgroundMargin(8, 8, 8, 0);

// Spacing between the button image and label.
constexpr int kImageLabelSpacingDp = 10;

// The border radius of the button background.
constexpr int kButtonRoundedBorderRadiusDp = 20;

// The color of the button background.
constexpr SkColor kButtonBackgroundColor =
    SkColorSetA(gfx::kGoogleGrey100, 0x19);

// The color of the button text.
constexpr SkColor kButtonTextColor = gfx::kGoogleGrey100;

// The color of the button icon.
constexpr SkColor kButtonIconColor = SkColorSetRGB(0xEB, 0xEA, 0xED);

std::unique_ptr<SkPath> GetButtonHighlightPath(views::View* view) {
  auto path = std::make_unique<SkPath>();

  gfx::Rect rect(view->GetLocalBounds());
  rect.Inset(kButtonBackgroundMargin);

  path->addRoundRect(gfx::RectToSkRect(rect), kButtonRoundedBorderRadiusDp,
                     kButtonRoundedBorderRadiusDp);
  return path;
}

void SetButtonHighlightPath(views::View* view) {
  view->SetProperty(views::kHighlightPathKey,
                    GetButtonHighlightPath(view).release());
}

class LoginShelfButton : public views::LabelButton,
                         public ash::SessionObserver {
 public:
  LoginShelfButton(views::ButtonListener* listener,
                   const base::string16& text,
                   const gfx::VectorIcon& icon)
      : LabelButton(listener, text), icon_(icon) {
    SetAccessibleName(text);
    SetImage(views::Button::STATE_NORMAL,
             gfx::CreateVectorIcon(icon, kButtonIconColor));
    SetImage(views::Button::STATE_DISABLED,
             gfx::CreateVectorIcon(
                 icon, SkColorSetA(kButtonIconColor,
                                   login_constants::kButtonDisabledAlpha)));
    SetFocusBehavior(FocusBehavior::ALWAYS);
    SetInstallFocusRingOnFocus(true);
    focus_ring()->SetColor(kFocusBorderColor);
    SetFocusPainter(nullptr);
    SetInkDropMode(InkDropMode::ON);
    set_has_ink_drop_action_on_click(true);
    set_ink_drop_base_color(kShelfInkDropBaseColor);
    set_ink_drop_visible_opacity(kShelfInkDropVisibleOpacity);

    // Layer rendering is required when the shelf background is visible, which
    // happens when the wallpaper is not blurred.
    SetPaintToLayer();
    layer()->SetFillsBoundsOpaquely(false);

    SetTextSubpixelRenderingEnabled(false);

    SetImageLabelSpacing(kImageLabelSpacingDp);
    SetTextColor(views::Button::STATE_NORMAL, kButtonTextColor);
    SetTextColor(views::Button::STATE_HOVERED, kButtonTextColor);
    SetTextColor(views::Button::STATE_PRESSED, kButtonTextColor);
    SetTextColor(
        views::Button::STATE_DISABLED,
        SkColorSetA(kButtonTextColor, login_constants::kButtonDisabledAlpha));
    label()->SetFontList(views::Label::GetDefaultFontList().Derive(
        1, gfx::Font::FontStyle::NORMAL, gfx::Font::Weight::NORMAL));
  }

  ~LoginShelfButton() override = default;

  // views::LabelButton:
  gfx::Insets GetInsets() const override {
    return gfx::Insets(kButtonMarginTopDp, kButtonMarginLeftDp,
                       kButtonMarginBottomDp, kButtonMarginRightDp);
  }

  void OnBoundsChanged(const gfx::Rect& previous_bounds) override {
    SetButtonHighlightPath(this);
    LabelButton::OnBoundsChanged(previous_bounds);
  }

  void PaintButtonContents(gfx::Canvas* canvas) override {
    cc::PaintFlags flags;
    flags.setAntiAlias(true);
    flags.setColor(kButtonBackgroundColor);
    flags.setStyle(cc::PaintFlags::kFill_Style);
    canvas->DrawPath(*GetButtonHighlightPath(this), flags);
  }

  std::unique_ptr<views::InkDrop> CreateInkDrop() override {
    auto ink_drop = std::make_unique<views::InkDropImpl>(this, size());
    ink_drop->SetShowHighlightOnHover(false);
    ink_drop->SetShowHighlightOnFocus(false);
    return ink_drop;
  }

  // ash::SessionObserver:
  void OnSessionStateChanged(session_manager::SessionState state) override {
    if (state == session_manager::SessionState::OOBE) {
      SetTextColor(views::Button::STATE_NORMAL, gfx::kGoogleGrey600);
      SetTextColor(views::Button::STATE_HOVERED, gfx::kGoogleGrey600);
      SetTextColor(views::Button::STATE_PRESSED, gfx::kGoogleGrey600);
      SetImage(views::Button::STATE_NORMAL,
               gfx::CreateVectorIcon(icon_, gfx::kGoogleGrey600));
    } else {
      SetTextColor(views::Button::STATE_NORMAL, kButtonTextColor);
      SetTextColor(views::Button::STATE_HOVERED, kButtonTextColor);
      SetTextColor(views::Button::STATE_PRESSED, kButtonTextColor);
      SetImage(views::Button::STATE_NORMAL,
               gfx::CreateVectorIcon(icon_, kButtonTextColor));
    }
  }

 private:
  ash::ScopedSessionObserver observer_{this};
  const gfx::VectorIcon& icon_;

  DISALLOW_COPY_AND_ASSIGN(LoginShelfButton);
};

}  // namespace

class KioskAppsButton : public views::MenuButton,
                        public views::MenuButtonListener,
                        public ui::SimpleMenuModel,
                        public ui::SimpleMenuModel::Delegate {
 public:
  KioskAppsButton(const base::string16& text, const gfx::ImageSkia& image)
      : MenuButton(text, this), ui::SimpleMenuModel(this) {
    SetFocusBehavior(FocusBehavior::ALWAYS);
    SetInstallFocusRingOnFocus(true);
    focus_ring()->SetColor(kFocusBorderColor);
    SetFocusPainter(nullptr);
    SetInkDropMode(InkDropMode::ON);
    set_has_ink_drop_action_on_click(true);
    set_ink_drop_base_color(kShelfInkDropBaseColor);
    set_ink_drop_visible_opacity(kShelfInkDropVisibleOpacity);

    // Layer rendering is required when the shelf background is visible, which
    // happens when the wallpaper is not blurred.
    SetPaintToLayer();
    layer()->SetFillsBoundsOpaquely(false);

    SetTextSubpixelRenderingEnabled(false);

    SetImage(views::Button::STATE_NORMAL, image);
    SetImageLabelSpacing(kImageLabelSpacingDp);
    SetTextColor(views::Button::STATE_NORMAL, kButtonTextColor);
    SetTextColor(views::Button::STATE_HOVERED, kButtonTextColor);
    SetTextColor(views::Button::STATE_PRESSED, kButtonTextColor);
    label()->SetFontList(views::Label::GetDefaultFontList().Derive(
        1, gfx::Font::FontStyle::NORMAL, gfx::Font::Weight::NORMAL));
  }

  // Replace the existing items list with a new list of kiosk app menu items.
  void SetApps(std::vector<mojom::KioskAppInfoPtr> kiosk_apps) {
    kiosk_apps_ = std::move(kiosk_apps);
    Clear();
    const gfx::Size kAppIconSize(16, 16);
    for (size_t i = 0; i < kiosk_apps_.size(); ++i) {
      gfx::ImageSkia icon = gfx::ImageSkiaOperations::CreateResizedImage(
          kiosk_apps_[i]->icon, skia::ImageOperations::RESIZE_GOOD,
          kAppIconSize);
      AddItemWithIcon(i, kiosk_apps_[i]->name, icon);
    }
  }

  bool HasApps() const { return !kiosk_apps_.empty(); }

  // views::MenuButton:
  gfx::Insets GetInsets() const override {
    return gfx::Insets(kButtonMarginTopDp, kButtonMarginLeftDp,
                       kButtonMarginBottomDp, kButtonMarginRightDp);
  }

  void OnBoundsChanged(const gfx::Rect& previous_bounds) override {
    SetButtonHighlightPath(this);
    LabelButton::OnBoundsChanged(previous_bounds);
  }

  void PaintButtonContents(gfx::Canvas* canvas) override {
    cc::PaintFlags flags;
    flags.setAntiAlias(true);
    flags.setColor(kButtonBackgroundColor);
    flags.setStyle(cc::PaintFlags::kFill_Style);
    canvas->DrawPath(*GetButtonHighlightPath(this), flags);
  }

  void SetVisible(bool visible) override {
    MenuButton::SetVisible(visible);
    if (visible)
      is_launch_enabled_ = true;
  }

  std::unique_ptr<views::InkDrop> CreateInkDrop() override {
    auto ink_drop = std::make_unique<views::InkDropImpl>(this, size());
    ink_drop->SetShowHighlightOnHover(false);
    ink_drop->SetShowHighlightOnFocus(false);
    return ink_drop;
  }

  // views::MenuButtonListener:
  void OnMenuButtonClicked(MenuButton* source,
                           const gfx::Point& point,
                           const ui::Event* event) override {
    if (!is_launch_enabled_)
      return;
    menu_runner_.reset(
        new views::MenuRunner(this, views::MenuRunner::HAS_MNEMONICS));

    gfx::Point origin(point);
    origin.set_x(point.x() - source->width());
    origin.set_y(point.y() - source->height());
    menu_runner_->RunMenuAt(source->GetWidget()->GetTopLevelWidget(), this,
                            gfx::Rect(origin, gfx::Size()),
                            views::MENU_ANCHOR_TOPLEFT, ui::MENU_SOURCE_NONE);
  }

  // ui::SimpleMenuModel:
  void ExecuteCommand(int command_id, int event_flags) override {
    DCHECK(command_id >= 0 &&
           base::checked_cast<size_t>(command_id) < kiosk_apps_.size());
    // Once an app is clicked on, don't allow any additional clicks until
    // the state is reset (when login screen reappears).
    is_launch_enabled_ = false;

    const mojom::KioskAppInfoPtr& kiosk_app = kiosk_apps_[command_id];

    switch (kiosk_app->identifier->which()) {
      case mojom::KioskAppIdentifier::Tag::ACCOUNT_ID:
        Shell::Get()->login_screen_controller()->LaunchArcKioskApp(
            kiosk_app->identifier->get_account_id());
        return;
      case mojom::KioskAppIdentifier::Tag::APP_ID:
        Shell::Get()->login_screen_controller()->LaunchKioskApp(
            kiosk_app->identifier->get_app_id());
        return;
      default:
        NOTREACHED();
    }
  }

  bool IsCommandIdChecked(int command_id) const override { return false; }

  bool IsCommandIdEnabled(int command_id) const override { return true; }

 private:
  std::unique_ptr<views::MenuRunner> menu_runner_;
  std::vector<mojom::KioskAppInfoPtr> kiosk_apps_;
  bool is_launch_enabled_ = true;

  DISALLOW_COPY_AND_ASSIGN(KioskAppsButton);
};

LoginShelfView::LoginShelfView(
    LockScreenActionBackgroundController* lock_screen_action_background)
    : lock_screen_action_background_(lock_screen_action_background),
      tray_action_observer_(this),
      lock_screen_action_background_observer_(this),
      shutdown_controller_observer_(this),
      login_screen_controller_observer_(this) {
  // We reuse the focusable state on this view as a signal that focus should
  // switch to the lock screen or status area. This view should otherwise not
  // be focusable.
  SetFocusBehavior(FocusBehavior::ALWAYS);
  SetLayoutManager(
      std::make_unique<views::BoxLayout>(views::BoxLayout::kHorizontal));

  auto add_button = [this](ButtonId id, int text_resource_id,
                           const gfx::VectorIcon& icon) {
    const base::string16 text = l10n_util::GetStringUTF16(text_resource_id);
    LoginShelfButton* button = new LoginShelfButton(this, text, icon);
    button->set_id(id);
    AddChildView(button);
  };
  add_button(kShutdown, IDS_ASH_SHELF_SHUTDOWN_BUTTON,
             kShelfShutdownButtonIcon);
  kiosk_apps_button_ = new KioskAppsButton(
      l10n_util::GetStringUTF16(IDS_ASH_SHELF_APPS_BUTTON),
      CreateVectorIcon(kShelfAppsButtonIcon, kButtonIconColor));
  kiosk_apps_button_->set_id(kApps);
  AddChildView(kiosk_apps_button_);
  add_button(kRestart, IDS_ASH_SHELF_RESTART_BUTTON, kShelfShutdownButtonIcon);
  add_button(kSignOut, IDS_ASH_SHELF_SIGN_OUT_BUTTON, kShelfSignOutButtonIcon);
  add_button(kCloseNote, IDS_ASH_SHELF_UNLOCK_BUTTON, kShelfUnlockButtonIcon);
  add_button(kCancel, IDS_ASH_SHELF_CANCEL_BUTTON, kShelfCancelButtonIcon);
  add_button(kBrowseAsGuest, IDS_ASH_BROWSE_AS_GUEST_BUTTON,
             kShelfBrowseAsGuestButtonIcon);
  add_button(kAddUser, IDS_ASH_ADD_USER_BUTTON, kShelfAddPersonButtonIcon);
  add_button(kParentAccess, IDS_ASH_PARENT_ACCESS_BUTTON,
             kParentAccessLockIcon);

  // Adds observers for states that affect the visiblity of different buttons.
  tray_action_observer_.Add(Shell::Get()->tray_action());
  shutdown_controller_observer_.Add(Shell::Get()->shutdown_controller());
  lock_screen_action_background_observer_.Add(lock_screen_action_background);
  login_screen_controller_observer_.Add(
      Shell::Get()->login_screen_controller());
  UpdateUi();
}

LoginShelfView::~LoginShelfView() = default;

void LoginShelfView::UpdateAfterSessionStateChange(SessionState state) {
  UpdateUi();
}

const char* LoginShelfView::GetClassName() const {
  return "LoginShelfView";
}

void LoginShelfView::OnFocus() {
  LOG(WARNING) << "LoginShelfView was focused, but this should never happen. "
                  "Forwarded focus to shelf widget with an unknown direction.";
  Shell::Get()->focus_cycler()->FocusWidget(
      Shelf::ForWindow(GetWidget()->GetNativeWindow())->shelf_widget());
}

void LoginShelfView::AboutToRequestFocusFromTabTraversal(bool reverse) {
  if (reverse) {
    // Focus should leave the system tray.
    Shell::Get()->system_tray_notifier()->NotifyFocusOut(reverse);

    // If the dialog is hidden, let views handle the focus automatically.
    // Otherwise, forward a focus request to the OOBE dialog.
    if (dialog_state_ != mojom::OobeDialogState::HIDDEN &&
        dialog_state_ != mojom::OobeDialogState::NONE) {
      Shell::Get()->login_screen_controller()->FocusOobeDialog();
    }
  } else {
    // Focus goes to status area.
    Shelf::ForWindow(GetWidget()->GetNativeWindow())
        ->GetStatusAreaWidget()
        ->status_area_widget_delegate()
        ->set_default_last_focusable_child(reverse);
    Shell::Get()->focus_cycler()->FocusWidget(
        Shelf::ForWindow(GetWidget()->GetNativeWindow())
            ->GetStatusAreaWidget());
  }
}

void LoginShelfView::GetAccessibleNodeData(ui::AXNodeData* node_data) {
  if (LockScreen::HasInstance()) {
    int previous_id = views::AXAuraObjCache::GetInstance()->GetID(
        LockScreen::Get()->widget());
    node_data->AddIntAttribute(ax::mojom::IntAttribute::kPreviousFocusId,
                               previous_id);
  }

  Shelf* shelf = Shelf::ForWindow(GetWidget()->GetNativeWindow());
  int next_id =
      views::AXAuraObjCache::GetInstance()->GetID(shelf->GetStatusAreaWidget());
  node_data->AddIntAttribute(ax::mojom::IntAttribute::kNextFocusId, next_id);
  node_data->role = ax::mojom::Role::kToolbar;
  node_data->SetName(l10n_util::GetStringUTF8(IDS_ASH_SHELF_ACCESSIBLE_NAME));
}

void LoginShelfView::ButtonPressed(views::Button* sender,
                                   const ui::Event& event) {
  UserMetricsRecorder::RecordUserClickOnShelfButton(
      GetUserClickTarget(sender->id()));
  switch (sender->id()) {
    case kShutdown:
    case kRestart:
      // |ShutdownController| will further distinguish the two cases based on
      // shutdown policy.
      Shell::Get()->lock_state_controller()->RequestShutdown(
          ShutdownReason::LOGIN_SHUT_DOWN_BUTTON);
      break;
    case kSignOut:
      base::RecordAction(base::UserMetricsAction("ScreenLocker_Signout"));
      Shell::Get()->session_controller()->RequestSignOut();
      break;
    case kCloseNote:
      Shell::Get()->tray_action()->CloseLockScreenNote(
          mojom::CloseLockScreenNoteReason::kUnlockButtonPressed);
      break;
    case kCancel:
      // If the Cancel button has focus, clear it. Otherwise the shelf within
      // active session may still be focused.
      GetFocusManager()->ClearFocus();
      Shell::Get()->login_screen_controller()->CancelAddUser();
      break;
    case kBrowseAsGuest:
      Shell::Get()->login_screen_controller()->LoginAsGuest();
      break;
    case kAddUser:
      Shell::Get()->login_screen_controller()->ShowGaiaSignin(
          true /*can_close*/, base::nullopt /*prefilled_account*/);
      break;
    default:
      NOTREACHED();
  }
}

void LoginShelfView::SetKioskApps(
    std::vector<mojom::KioskAppInfoPtr> kiosk_apps) {
  kiosk_apps_button_->SetApps(std::move(kiosk_apps));
  UpdateUi();
}

void LoginShelfView::SetLoginDialogState(mojom::OobeDialogState state) {
  dialog_state_ = state;
  UpdateUi();
}

void LoginShelfView::SetAllowLoginAsGuest(bool allow_guest) {
  allow_guest_ = allow_guest;
  UpdateUi();
}

void LoginShelfView::SetShowParentAccessButton(bool show) {
  show_parent_access_ = show;
  UpdateUi();
}

void LoginShelfView::SetShowGuestButtonInOobe(bool show) {
  allow_guest_in_oobe_ = show;
  UpdateUi();
}

void LoginShelfView::SetAddUserButtonEnabled(bool enable_add_user) {
  GetViewByID(kAddUser)->SetEnabled(enable_add_user);
}

void LoginShelfView::SetShutdownButtonEnabled(bool enable_shutdown_button) {
  GetViewByID(kShutdown)->SetEnabled(enable_shutdown_button);
}

void LoginShelfView::OnLockScreenNoteStateChanged(
    mojom::TrayActionState state) {
  UpdateUi();
}

void LoginShelfView::OnLockScreenActionBackgroundStateChanged(
    LockScreenActionBackgroundState state) {
  UpdateUi();
}

void LoginShelfView::OnShutdownPolicyChanged(bool reboot_on_shutdown) {
  UpdateUi();
}

void LoginShelfView::OnOobeDialogStateChanged(mojom::OobeDialogState state) {
  SetLoginDialogState(state);
}

void LoginShelfView::OnUsersChanged(
    const std::vector<mojom::LoginUserInfoPtr>& users) {
  login_screen_has_users_ = !users.empty();
  UpdateUi();
}

bool LoginShelfView::LockScreenActionBackgroundAnimating() const {
  return lock_screen_action_background_->state() ==
             LockScreenActionBackgroundState::kShowing ||
         lock_screen_action_background_->state() ==
             LockScreenActionBackgroundState::kHiding;
}

void LoginShelfView::UpdateUi() {
  SessionState session_state =
      Shell::Get()->session_controller()->GetSessionState();
  if (session_state == SessionState::ACTIVE) {
    // The entire view was set invisible. The buttons are also set invisible
    // to avoid affecting calculation of the shelf size.
    for (int i = 0; i < child_count(); ++i)
      child_at(i)->SetVisible(false);
    return;
  }
  ++ui_update_count_;
  bool show_reboot = Shell::Get()->shutdown_controller()->reboot_on_shutdown();
  mojom::TrayActionState tray_action_state =
      Shell::Get()->tray_action()->GetLockScreenNoteState();
  bool is_locked = (session_state == SessionState::LOCKED);
  bool is_lock_screen_note_in_foreground =
      (tray_action_state == mojom::TrayActionState::kActive ||
       tray_action_state == mojom::TrayActionState::kLaunching) &&
      !LockScreenActionBackgroundAnimating();

  // The following should be kept in sync with |updateUI_| in md_header_bar.js.
  GetViewByID(kShutdown)->SetVisible(!show_reboot &&
                                     !is_lock_screen_note_in_foreground);
  GetViewByID(kRestart)->SetVisible(show_reboot &&
                                    !is_lock_screen_note_in_foreground);
  GetViewByID(kSignOut)->SetVisible(is_locked &&
                                    !is_lock_screen_note_in_foreground);
  GetViewByID(kCloseNote)
      ->SetVisible(is_locked && is_lock_screen_note_in_foreground);
  GetViewByID(kCancel)->SetVisible(session_state ==
                                   SessionState::LOGIN_SECONDARY);
  GetViewByID(kParentAccess)->SetVisible(is_locked && show_parent_access_);

  bool is_login_primary = (session_state == SessionState::LOGIN_PRIMARY);
  bool dialog_visible = dialog_state_ != mojom::OobeDialogState::HIDDEN;
  bool is_oobe = (session_state == SessionState::OOBE);

  // Show guest button if:
  // 1. It's in login screen or OOBE. Note: In OOBE, the guest button visibility
  // is manually controlled by the WebUI.
  // 2. Guest login is allowed.
  // 3. OOBE UI dialog is not currently showing wrong HWID warning screen or
  // SAML password confirmation screen.
  // 4. OOBE UI dialog is not currently showing gaia signin screen, or if there
  // are no user views available. If there are no user pods (i.e. Gaia is the
  // only signin option), the guest button should be shown if allowed.
  GetViewByID(kBrowseAsGuest)
      ->SetVisible(
          allow_guest_ &&
          dialog_state_ != mojom::OobeDialogState::WRONG_HWID_WARNING &&
          dialog_state_ != mojom::OobeDialogState::SAML_PASSWORD_CONFIRM &&
          dialog_state_ != mojom::OobeDialogState::SYNC_CONSENT &&
          (dialog_state_ != mojom::OobeDialogState::GAIA_SIGNIN ||
           !login_screen_has_users_) &&
          (is_login_primary || (is_oobe && allow_guest_in_oobe_)));

  // Show add user button when it's in login screen and Oobe UI dialog is not
  // visible. The button should not appear if the device is not connected to a
  // network.
  GetViewByID(kAddUser)->SetVisible(!dialog_visible && is_login_primary);
  // Show kiosk apps button if:
  // 1. It's in login screen.
  // 2. There are Kiosk apps available.
  // 3. Oobe UI dialog is not visible or is currently showing gaia signin
  // screen.
  kiosk_apps_button_->SetVisible(
      (!dialog_visible ||
       dialog_state_ == mojom::OobeDialogState::GAIA_SIGNIN) &&
      kiosk_apps_button_->HasApps() && is_login_primary);
  Layout();
}

}  // namespace ash