// Copyright 2013 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef CHROME_BROWSER_UI_VIEWS_FRAME_DBUS_APPMENU_H_
#define CHROME_BROWSER_UI_VIEWS_FRAME_DBUS_APPMENU_H_

#include <map>
#include <string>

#include "base/containers/flat_set.h"
#include "base/containers/span.h"
#include "base/memory/raw_ptr.h"
#include "base/memory/weak_ptr.h"
#include "base/scoped_observation.h"
#include "chrome/browser/command_observer.h"
#include "chrome/browser/profiles/avatar_menu.h"
#include "chrome/browser/profiles/avatar_menu_observer.h"
#include "chrome/browser/ui/browser_window/public/browser_collection_observer.h"
#include "components/dbus/menu/menu.h"
#include "components/history/core/browser/history_types.h"
#include "components/history/core/browser/top_sites.h"
#include "components/history/core/browser/top_sites_observer.h"
#include "components/prefs/pref_change_registrar.h"
#include "components/sessions/core/tab_restore_service.h"
#include "components/sessions/core/tab_restore_service_observer.h"
#include "ui/aura/window_tree_host.h"
#include "ui/menus/simple_menu_model.h"

namespace ui {
class Accelerator;
class PlatformWindow;
}  // namespace ui

class GlobalBrowserCollection;
class BrowserView;
struct DbusAppmenuCommand;
class Profile;
class BrowserWindowInterface;

// Controls the Mac style menu bar on Linux desktop environments.
//
// Unity had a MacOS-like menu bar at the top of the screen that changed
// depending on the active window.  Unity has been discontinued but the menu
// survived and is usually referred to as DBus AppMenu.  There is support for it
// in KDE Plasma in form of a widget that can be inserted into a panel.
class DbusAppmenu : public AvatarMenuObserver,
                    public BrowserCollectionObserver,
                    public CommandObserver,
                    public history::TopSitesObserver,
                    public sessions::TabRestoreServiceObserver,
                    public ui::SimpleMenuModel::Delegate {
 public:
  DbusAppmenu(BrowserView* browser_view,
              ui::PlatformWindow* platform_window,
              uint32_t browser_frame_id);

  DbusAppmenu(const DbusAppmenu&) = delete;
  DbusAppmenu& operator=(const DbusAppmenu&) = delete;

  ~DbusAppmenu() override;

  void Initialize(DbusMenu::InitializedCallback callback);

  // Creates the object path for DbusemenuServer which is attached to |window|.
  std::string GetPath() const;

  uint32_t browser_frame_id() const { return browser_frame_id_; }
  ui::PlatformWindow* platform_window() const { return platform_window_; }

 private:
  struct HistoryItem;

  // Creates a whole menu defined with |commands| and titled with the string
  // |string_id|. Then appends it to |root_menu_|.
  ui::SimpleMenuModel* BuildStaticMenu(
      int string_id,
      base::span<const DbusAppmenuCommand> commands);

  // Creates a HistoryItem from the data in |entry|.
  std::unique_ptr<HistoryItem> HistoryItemForTab(
      const sessions::tab_restore::Tab& entry);

  // Creates a menu item form |item| and inserts it in |menu| at |index|.
  void AddHistoryItemToMenu(std::unique_ptr<HistoryItem> item,
                            ui::SimpleMenuModel* menu,
                            int index);

  // Creates a menu item with the given |id| and |title| and inserts it in the
  // history_menu_ at |index|. The creates a submenu with some standard items
  // and an item for each tab in |tabs|.
  void AddEntryToHistoryMenu(
      SessionID id,
      std::u16string title,
      int index,
      const std::vector<std::unique_ptr<sessions::tab_restore::Tab>>& tabs,
      int restore_string_id);

  // Sends a message off to History for data.
  void GetTopSitesData();

  // Callback to receive data requested from GetTopSitesData().
  void OnTopSitesReceived(const history::MostVisitedURLList& visited_list);

  // Updates the visibility of the bookmark bar on pref changes.
  void OnBookmarkBarVisibilityChanged();

  void RebuildProfilesMenu();

  // This will remove all menu items in |history_menu_| starting from the item
  // with command |header_command_id| up to the item with command
  // MENU_SEPARATOR, non-inclusive.  Returns the index of the separator.
  int ClearHistoryMenuSection(int header_command_id);

  // Start listening for enabled state changes for |command|.
  void RegisterCommandObserver(int command);

  // Returns a command ID for use in menus.  The command will not conflict with
  // Chrome commands or reserved commands.
  int NextCommandId();

  // AvatarMenuObserver:
  void OnAvatarMenuChanged(AvatarMenu* avatar_menu) override;

  // BrowserCollectionObserver:
  void OnBrowserActivated(BrowserWindowInterface* browser) override;

  // CommandObserver:
  void EnabledStateChangedForCommand(int id, bool enabled) override;

  // history::TopSitesObserver:
  void TopSitesLoaded(history::TopSites* top_sites) override;
  void TopSitesChanged(history::TopSites* top_sites,
                       ChangeReason change_reason) override;

  // TabRestoreServiceObserver:
  void TabRestoreServiceChanged(sessions::TabRestoreService* service) override;
  void TabRestoreServiceDestroyed(
      sessions::TabRestoreService* service) override;

  // ui::SimpleMenuModel::Delegate:
  bool IsCommandIdChecked(int command_id) const override;
  bool IsCommandIdEnabled(int command_id) const override;
  void ExecuteCommand(int command_id, int event_flags) override;
  void OnMenuWillShow(ui::SimpleMenuModel* source) override;
  bool GetAcceleratorForCommandId(int command_id,
                                  ui::Accelerator* accelerator) const override;

  // State for the browser window we're tracking.
  const raw_ptr<BrowserWindowInterface> browser_;
  raw_ptr<Profile> profile_;
  raw_ptr<BrowserView> browser_view_;
  raw_ptr<ui::PlatformWindow> platform_window_;
  // XID of the browser's frame window that owns this menu.  Deliberately stored
  // as plain int (and not as x11::Window) because it is never used for any
  // calls to the X server, but it is always used for building string paths and
  // messages, for which it is converted to int (see GetPath() and calls to our
  // browser_frame_id() in DbusAppmenuRegistrar).
  const uint32_t browser_frame_id_;

  // Has Initialize() been called?
  bool initialized_ = false;

  // Menu models.  Menus don't own their children, so we must own them.
  // |toplevel_menus_| are children of |root_menu_|.
  // |recently_closed_window_menus_| are children of |history_menu_|.
  // |history_menu_| and |profiles_menu_| are owned by |toplevel_menus_|.
  std::unique_ptr<ui::SimpleMenuModel> root_menu_;
  std::vector<std::unique_ptr<ui::SimpleMenuModel>> toplevel_menus_;
  std::vector<std::unique_ptr<ui::SimpleMenuModel>>
      recently_closed_window_menus_;
  raw_ptr<ui::SimpleMenuModel> history_menu_ = nullptr;
  raw_ptr<ui::SimpleMenuModel> profiles_menu_ = nullptr;

  // The DBus menu service.
  // Should be destroyed prior to ui::MenuModels because DBusMenu::MenuItem
  // holds a raw_ptr to a ui::ModelModel.
  std::unique_ptr<DbusMenu> menu_service_;

  // Tracks value of the kShowBookmarkBar preference.
  PrefChangeRegistrar pref_change_registrar_;

  scoped_refptr<history::TopSites> top_sites_;

  raw_ptr<sessions::TabRestoreService> tab_restore_service_;  // weak

  std::unique_ptr<AvatarMenu> avatar_menu_;

  base::ScopedObservation<history::TopSites, history::TopSitesObserver>
      scoped_observation_{this};

  // Maps from history item command ID to HistoryItem data.
  std::map<int, std::unique_ptr<HistoryItem>> history_items_;

  // Maps from profile item command ID to an index into |avatar_menu_|, at the
  // time the menu was created.
  std::map<int, int> profile_commands_;
  int active_profile_index_ = -1;

  base::flat_set<int> observed_commands_;

  int last_command_id_;

  base::ScopedObservation<GlobalBrowserCollection, BrowserCollectionObserver>
      browser_collection_observation_{this};

  // For callbacks may be run after destruction.
  base::WeakPtrFactory<DbusAppmenu> weak_ptr_factory_{this};
};

#endif  // CHROME_BROWSER_UI_VIEWS_FRAME_DBUS_APPMENU_H_