// Aseprite UI Library
// Copyright (C) 2019-2024  Igara Studio S.A.
// Copyright (C) 2001-2017  David Capello
//
// This file is released under the terms of the MIT license.
// Read LICENSE.txt for more information.

#ifndef UI_VIEW_H_INCLUDED
#define UI_VIEW_H_INCLUDED
#pragma once

#include "gfx/point.h"
#include "gfx/size.h"
#include "ui/message.h"
#include "ui/scroll_bar.h"
#include "ui/viewport.h"
#include "ui/widget.h"

#include <optional>

namespace ui {
class ScrollRegionEvent;

class ViewableWidget {
public:
  virtual ~ViewableWidget() {}
  virtual void onScrollRegion(ScrollRegionEvent& ev) = 0;
};

class View : public Widget,
             public ScrollableViewDelegate {
public:
  View();

  bool hasScrollBars();
  ScrollBar* horizontalBar() { return &m_scrollbar_h; }
  ScrollBar* verticalBar() { return &m_scrollbar_v; }

  void attachToView(Widget* viewableWidget);
  Widget* attachedWidget();

  void hideScrollBars();
  void showScrollBars();
  void makeVisibleAllScrollableArea();

  // Returns the maximum viewable size requested by the attached
  // widget in the viewport.
  gfx::Size getScrollableSize() const;
  void setScrollableSize(const gfx::Size& sz, const bool setScrollPos = true);

  // Returns the visible/available size to see the attached widget.
  gfx::Size visibleSize() const override;
  gfx::Point viewScroll() const override;
  void setViewScroll(const gfx::Point& pt) override;

  void updateView(const bool restoreScrollPos = true);

  Viewport* viewport();
  gfx::Rect viewportBounds() const;

  // For viewable widgets
  static View* getView(const Widget* viewableWidget);

  // Scroll the given widget's view with the mouse wheel event.
  // The default multiplier is 3 * textHeight()
  static void scrollByMessage(const Widget* viewableWidget,
                              Message* message,
                              std::optional<int> multiplier = std::nullopt);

protected:
  // Events
  bool onProcessMessage(Message* msg) override;
  void onInitTheme(InitThemeEvent& ev) override;
  void onResize(ResizeEvent& ev) override;
  void onSizeHint(SizeHintEvent& ev) override;

  virtual void onSetViewScroll(const gfx::Point& pt);
  virtual void onScrollRegion(ScrollRegionEvent& ev);
  virtual void onScrollChange();

private:
  void updateAttachedWidgetBounds(const gfx::Point& scrollPos);
  gfx::Point limitScrollPosToViewport(const gfx::Point& pt) const;

  bool m_hasBars;
  Viewport m_viewport;
  ScrollBar m_scrollbar_h;
  ScrollBar m_scrollbar_v;
};

} // namespace ui

#endif
