// Aseprite UI Library
// Copyright (C) 2020-2022  Igara Studio S.A.
// Copyright (C) 2001-2018  David Capello
//
// This file is released under the terms of the MIT license.
// Read LICENSE.txt for more information.

#ifndef UI_MENU_H_INCLUDED
#define UI_MENU_H_INCLUDED
#pragma once

#include "obs/signal.h"
#include "ui/register_message.h"
#include "ui/separator.h"
#include "ui/widget.h"
#include "ui/window.h"

#include <memory>

namespace ui {

  class MenuBoxWindow;
  class MenuItem;
  class Timer;
  struct MenuBaseData;

  class Menu : public Widget {
  public:
    Menu();
    ~Menu();

    void showPopup(const gfx::Point& pos,
                   Display* parentDisplay);
    Widget* findItemById(const char* id) const;

    // Returns the MenuItem that has as submenu this menu.
    MenuItem* getOwnerMenuItem() {
      return m_menuitem;
    }

    obs::signal<void()> OpenPopup;

  protected:
    virtual void onPaint(PaintEvent& ev) override;
    virtual void onResize(ResizeEvent& ev) override;
    virtual void onSizeHint(SizeHintEvent& ev) override;
    virtual void onOpenPopup();

  private:
    void setOwnerMenuItem(MenuItem* ownerMenuItem) {
      m_menuitem = ownerMenuItem;
    }

    void closeAll();

    MenuItem* getHighlightedItem();
    void highlightItem(MenuItem* menuitem, bool click, bool open_submenu, bool select_first_child);
    void unhighlightItem();

    MenuItem* m_menuitem;         // From where the menu was open

    friend class MenuBox;
    friend class MenuItem;
  };

  class MenuBox : public Widget {
  public:
    MenuBox(WidgetType type = kMenuBoxWidget);
    ~MenuBox();

    Menu* getMenu();
    void setMenu(Menu* menu);

    MenuBaseData* getBase() {
      return m_base.get();
    }

    // Closes all menu-boxes and goes back to the normal state of the
    // menu-bar.
    void cancelMenuLoop();

  protected:
    virtual bool onProcessMessage(Message* msg) override;
    virtual void onResize(ResizeEvent& ev) override;
    virtual void onSizeHint(SizeHintEvent& ev) override;
    MenuBaseData* createBase();

  private:
    void closePopup();
    void startFilteringMouseDown();
    void stopFilteringMouseDown();

    std::unique_ptr<MenuBaseData> m_base;

    friend class Menu;
    friend class MenuItem;
  };

  class MenuBar : public MenuBox {
  public:
    enum class ProcessTopLevelShortcuts { kNo, kYes };

    MenuBar(ProcessTopLevelShortcuts processShortcuts);

    bool processTopLevelShortcuts() const {
      return m_processTopLevelShortcuts;
    }

    static bool expandOnMouseover();
    static void setExpandOnMouseover(bool state);

  private:
    // True if we should open top-level menus with Alt+mnemonic (this
    // flag is not used by Aseprite), top-level menus are opened with
    // the ShowMenu command now.
    bool m_processTopLevelShortcuts;
    static bool m_expandOnMouseover;
  };

  class MenuItem : public Widget {
  public:
    MenuItem(const std::string& text);
    ~MenuItem();

    Menu* getSubmenu();
    void setSubmenu(Menu* submenu);

    // Open the submenu of this menu item (the menu item should be
    // positioned in a correct position on the screen).
    void openSubmenu();

    bool isHighlighted() const;
    void setHighlighted(bool state);

    // Returns true if the MenuItem has a submenu.
    bool hasSubmenu() const;

    // Returns true if the submenu is opened.
    bool hasSubmenuOpened() const {
      return (m_submenu_menubox != nullptr);
    }

    // Returns the menu-box where the sub-menu has been opened, or
    // just nullptr if the sub-menu is closed.
    MenuBox* getSubmenuContainer() const {
      return m_submenu_menubox;
    }

    void executeClick();
    void validateItem();

    // Fired when the menu item is clicked.
    obs::signal<void()> Click;

  protected:
    bool onProcessMessage(Message* msg) override;
    void onInitTheme(InitThemeEvent& ev) override;
    void onPaint(PaintEvent& ev) override;
    void onSizeHint(SizeHintEvent& ev) override;
    virtual void onClick();
    virtual void onValidate();

    bool inBar() const;

  private:
    void openSubmenu(bool select_first);
    void closeSubmenu(bool last_of_close_chain);
    void startTimer();
    void stopTimer();

    bool m_highlighted;           // Is it highlighted?
    Menu* m_submenu;              // The sub-menu
    MenuBox* m_submenu_menubox;   // The opened menubox for this menu-item
    std::unique_ptr<Timer> m_submenu_timer; // Timer to open the submenu

    friend class Menu;
    friend class MenuBox;
    friend class MenuBoxWindow;
  };

  class MenuSeparator : public Separator {
  public:
    MenuSeparator() : Separator("", HORIZONTAL) {
    }
  };

  class MenuBoxWindow : public Window {
  public:
    MenuBoxWindow(MenuItem* menuitem = nullptr);
    ~MenuBoxWindow();
    MenuBox* menubox() { return &m_menubox; }
  protected:
    bool onProcessMessage(Message* msg) override;
  private:
    MenuBox m_menubox;
    MenuItem* m_menuitem;
  };

  extern RegisterMessage kOpenMenuItemMessage;
  extern RegisterMessage kCloseMenuItemMessage;
  extern RegisterMessage kClosePopupMessage;
  extern RegisterMessage kExecuteMenuItemMessage;

} // namespace ui

#endif