text: /*
   * Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
   *
   * SPDX-License-Identifier: BSD-2-Clause
   */
  
  #pragma once
  
  #include <LibGUI/Widget.h>
  
  namespace GUI {
  
  class TabWidget : public Widget {
      C_OBJECT(TabWidget)
  public:
      enum TabPosition {
          Top,
          Bottom,
      };
  
      virtual ~TabWidget() override;
  
      TabPosition tab_position() const { return m_tab_position; }
      void set_tab_position(TabPosition);
  
      int active_tab_index() const;
  
      Widget* active_widget() { return m_active_widget.ptr(); }
      const Widget* active_widget() const { return m_active_widget.ptr(); }
      void set_active_widget(Widget*);
      void set_tab_index(int);
  
      int bar_height() const { return m_bar_visible ? 21 : 0; }
  
      int container_padding() const { return m_container_padding; }
      void set_container_padding(int padding) { m_container_padding = padding; }
  
      void add_widget(const StringView&, Widget&);
      void remove_widget(Widget&);
  
      template<class T, class... Args>
      T& add_tab(const StringView& title, Args&&... args)
      {
          auto t = T::construct(forward<Args>(args)...);
          add_widget(title, *t);
          return *t;
      }
  
      void remove_tab(Widget& tab) { remove_widget(tab); }
  
      void set_tab_title(Widget& tab, const StringView& title);
      void set_tab_icon(Widget& tab, const Gfx::Bitmap*);
  
      void activate_next_tab();
      void activate_previous_tab();
  
      void set_text_alignment(Gfx::TextAlignment alignment) { m_text_alignment = alignment; }
      Gfx::TextAlignment text_alignment() const { return m_text_alignment; }
  
      bool uniform_tabs() const { return m_uniform_tabs; }
      void set_uniform_tabs(bool uniform_tabs) { m_uniform_tabs = uniform_tabs; }
      int uniform_tab_width() const;
  
      void set_bar_visible(bool bar_visible);
      bool is_bar_visible() const { return m_bar_visible; };
  
      Function<void(size_t)> on_tab_count_change;
      Function<void(Widget&)> on_change;
      Function<void(Widget&)> on_middle_click;
      Function<void(Widget&, const ContextMenuEvent&)> on_context_menu_request;
  
  protected:
      TabWidget();
  
      virtual void paint_event(PaintEvent&) override;
      virtual void child_event(Core::ChildEvent&) override;
      virtual void resize_event(ResizeEvent&) override;
      virtual void mousedown_event(MouseEvent&) override;
      virtual void mousemove_event(MouseEvent&) override;
      virtual void leave_event(Core::Event&) override;
      virtual void keydown_event(KeyEvent&) override;
      virtual void context_menu_event(ContextMenuEvent&) override;
  
  private:
      Gfx::IntRect child_rect_for_size(const Gfx::IntSize&) const;
      Gfx::IntRect button_rect(int index) const;
      Gfx::IntRect bar_rect() const;
      Gfx::IntRect container_rect() const;
      void update_bar();
      void update_focus_policy();
      int bar_margin() const { return 2; }
  
      RefPtr<Widget> m_active_widget;
  
      struct TabData {
          int width(const Gfx::Font&) const;
          String title;
          RefPtr<Gfx::Bitmap> icon;
          Widget* widget { nullptr };
      };
      Vector<TabData> m_tabs;
      TabPosition m_tab_position { TabPosition::Top };
      int m_hovered_tab_index { -1 };
      int m_container_padding { 2 };
      Gfx::TextAlignment m_text_alignment { Gfx::TextAlignment::Center };
      bool m_uniform_tabs { false };
      bool m_bar_visible { true };
  };
  
  }
  