// Aseprite UI Library
// Copyright (C) 2018-2025  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_WIDGET_H_INCLUDED
#define UI_WIDGET_H_INCLUDED
#pragma once

#include "gfx/border.h"
#include "gfx/color.h"
#include "gfx/point.h"
#include "gfx/rect.h"
#include "gfx/region.h"
#include "gfx/size.h"
#include "obs/signal.h"
#include "text/font.h"
#include "text/text_blob.h"
#include "ui/base.h"
#include "ui/component.h"
#include "ui/graphics.h"
#include "ui/widget_type.h"
#include "ui/widgets_list.h"

#include <string>

#define ASSERT_VALID_WIDGET(widget) ASSERT((widget) != nullptr)

namespace ui {

class Display;
class InitThemeEvent;
class KeyMessage;
class LoadLayoutEvent;
class Manager;
class Message;
class MouseMessage;
class PaintEvent;
class ResizeEvent;
class SaveLayoutEvent;
class SizeHintEvent;
class Style;
class Theme;
class Window;
class DragEvent;

class Widget : public Component {
public:
  // ===============================================================
  // CTOR & DTOR
  // ===============================================================

  Widget(WidgetType type = kGenericWidget);
  virtual ~Widget();

  // Safe way to delete a widget when it is not in the manager message
  // queue anymore.
  void deferDelete();

  // Main properties.

  WidgetType type() const { return m_type; }
  void setType(WidgetType type) { m_type = type; } // TODO remove this function

  const std::string& id() const { return m_id; }
  void setId(const char* id) { m_id = id; }

  int flags() const { return m_flags; }
  bool hasFlags(int flags) const { return ((m_flags & flags) == flags); }
  void enableFlags(int flags) { m_flags |= flags; }
  void disableFlags(int flags) { m_flags &= ~flags; }

  int align() const { return (m_flags & ALIGN_MASK); }
  void setAlign(int align) { m_flags = ((m_flags & PROPERTIES_MASK) | (align & ALIGN_MASK)); }

  // Text property.

  bool hasText() const { return hasFlags(HAS_TEXT); }

  const std::string& text() const { return m_text; }
  int textInt() const;
  double textDouble() const;
  void setText(const std::string& text);
  void setTextf(const char* text, ...);
  void setTextQuiet(const std::string& text);

  text::TextBlobRef textBlob() const;
  int textWidth() const;
  int textHeight() const;

  gfx::Size textSize() const { return gfx::Size(textWidth(), textHeight()); }

  // ===============================================================
  // COMMON PROPERTIES
  // ===============================================================

  // True if this widget and all its ancestors are visible.
  bool isVisible() const;
  void setVisible(bool state);

  // True if this widget can receive user input (is not disabled).
  bool isEnabled() const;
  void setEnabled(bool state);

  // True if this widget is selected (pushed in case of a button, or
  // checked in the case of a check-box).
  bool isSelected() const;
  void setSelected(bool state);

  // True if this widget wants more space when it's inside a Box
  // parent.
  bool isExpansive() const;
  void setExpansive(bool state);

  // True if this is a decorative widget created by the current
  // theme. Decorative widgets are arranged by the theme instead that
  // the parent's widget.
  bool isDecorative() const;
  void setDecorative(bool state);

  // True if this widget can receive the keyboard focus.
  bool isFocusStop() const;
  void setFocusStop(bool state);

  // True if this widget wants the focus by default when it's shown by
  // first time (e.g. when its parent window is opened).
  void setFocusMagnet(bool state);
  bool isFocusMagnet() const;

  // ===============================================================
  // LOOK & FEEL
  // ===============================================================

  const text::FontRef& font() const;
  void setFont(const text::FontRef& font);

  // Gets the background color of the widget.
  gfx::Color bgColor() const
  {
    if (gfx::geta(m_bgColor) == 0 && m_parent)
      return m_parent->bgColor();
    return m_bgColor;
  }

  // Sets the background color of the widget
  void setBgColor(gfx::Color color);

  Theme* theme() const { return m_theme; }
  Style* style() const { return m_style; }
  void setTheme(Theme* theme);
  virtual void setStyle(Style* style);
  void initTheme();

  // ===============================================================
  // PARENTS & CHILDREN
  // ===============================================================

  Window* window() const;
  Widget* parent() const { return m_parent; }
  int parentIndex() const { return m_parentIndex; }
  Manager* manager() const;
  Display* display() const;

  // Returns a list of children.
  const WidgetsList& children() const { return m_children; }
  bool hasChildren() const { return !m_children.empty(); }

  Widget* at(int index) { return m_children[index]; }
  int getChildIndex(Widget* child);

  // Returns the first/last child or nullptr if it doesn't exist.
  Widget* firstChild() { return (hasChildren() ? m_children.front() : nullptr); }
  Widget* lastChild() { return (hasChildren() ? m_children.back() : nullptr); }

  // Returns the next or previous siblings.
  Widget* nextSibling();
  Widget* previousSibling();

  Widget* pick(const gfx::Point& pt, const bool checkParentsVisibility = true) const;
  virtual Widget* pickFromScreenPos(const gfx::Point& screenPos) const;

  bool hasChild(Widget* child);
  bool hasAncestor(Widget* ancestor);
  Widget* findChild(const char* id) const;

  // Returns a widget in the same window that is located "sibling".
  Widget* findSibling(const char* id) const;

  // Finds a child with the specified ID and dynamic-casts it to type
  // T.
  template<class T>
  T* findChildT(const char* id) const
  {
    return dynamic_cast<T*>(findChild(id));
  }

  template<class T>
  T* findFirstChildByType() const
  {
    for (auto child : m_children) {
      if (T* specificChild = dynamic_cast<T*>(child))
        return specificChild;
    }
    return nullptr;
  }

  void addChild(Widget* child);
  void removeChild(Widget* child);
  void removeAllChildren();
  void replaceChild(Widget* oldChild, Widget* newChild);
  void insertChild(int index, Widget* child);
  void moveChildTo(Widget* thisChild, Widget* toThisPosition);

  // ===============================================================
  // LAYOUT & CONSTRAINT
  // ===============================================================

  void layout();
  void loadLayout();
  void saveLayout();

  void setDecorativeWidgetBounds();

  // ===============================================================
  // POSITION & GEOMETRY
  // ===============================================================

  gfx::Rect bounds() const { return m_bounds; }
  gfx::Point origin() const { return m_bounds.origin(); }
  gfx::Size size() const { return m_bounds.size(); }

  gfx::Rect clientBounds() const { return gfx::Rect(0, 0, m_bounds.w, m_bounds.h); }

  gfx::Rect childrenBounds() const;
  gfx::Rect clientChildrenBounds() const;

  // Bounds of this widget or window on native screen/desktop coordinates.
  gfx::Rect boundsOnScreen() const;

  // Sets the bounds of the widget generating a onResize() event.
  void setBounds(const gfx::Rect& rc);

  // Sets the bounds of the widget without generating any kind of
  // event. This member function must be used if you override
  // onResize() and want to change the size of the widget without
  // generating recursive onResize() events.
  void setBoundsQuietly(const gfx::Rect& rc);
  void offsetWidgets(int dx, int dy);

  const gfx::Size& minSize() const { return m_minSize; }
  const gfx::Size& maxSize() const { return m_maxSize; }
  void setMinSize(const gfx::Size& sz);
  void setMaxSize(const gfx::Size& sz);
  void setMinMaxSize(const gfx::Size& minSz, const gfx::Size& maxSz);
  void resetMinSize();
  void resetMaxSize();

  const gfx::Border& border() const { return m_border; }
  void setBorder(const gfx::Border& border);

  int childSpacing() const { return m_childSpacing; }
  void setChildSpacing(int childSpacing);

  void noBorderNoChildSpacing();

  // Flags for getDrawableRegion()
  enum DrawableRegionFlags {
    kCutTopWindows = 1, // Cut areas where are windows on top.
    kUseChildArea = 2,  // Use areas where are children.
    kCutTopWindowsAndUseChildArea = kCutTopWindows | kUseChildArea,
  };

  void getRegion(gfx::Region& region);
  void getDrawableRegion(gfx::Region& region, DrawableRegionFlags flags);

  gfx::Point toClient(const gfx::Point& pt) const { return pt - m_bounds.origin(); }
  gfx::Rect toClient(const gfx::Rect& rc) const
  {
    return gfx::Rect(rc).offset(-m_bounds.x, -m_bounds.y);
  }

  void getTextIconInfo(gfx::Rect* box,
                       gfx::Rect* text = nullptr,
                       gfx::Rect* icon = nullptr,
                       int icon_align = 0,
                       int icon_w = 0,
                       int icon_h = 0);

  // Y-axis location where the text baseline should be located in the
  // middle of the widget.
  float textBaseline() const;

  // ===============================================================
  // REFRESH ISSUES
  // ===============================================================

  bool isDoubleBuffered() const;
  void setDoubleBuffered(bool doubleBuffered);

  bool isTransparent() const;
  void setTransparent(bool transparent);

  void invalidate();
  void invalidateRect(const gfx::Rect& rect);
  void invalidateRegion(const gfx::Region& region);

  // Returns the region to generate PaintMessages. It's cleared
  // after flushRedraw() is called.
  const gfx::Region& getUpdateRegion() const { return m_updateRegion; }

  // Generates paint messages for the current update region.
  void flushRedraw();

  // Wakes up the system's events queue to process the currently enqueued UI
  // messages.
  void flushMessages() const;

  GraphicsPtr getGraphics(const gfx::Rect& clip);

  // ===============================================================
  // GUI MANAGER
  // ===============================================================

  bool sendMessage(Message* msg);
  void closeWindow();

  void broadcastMouseMessage(const gfx::Point& screenPos, WidgetsList& targets);

  // ===============================================================
  // SIZE & POSITION
  // ===============================================================

  gfx::Size sizeHint();
  gfx::Size sizeHint(const gfx::Size& fitIn);
  void setSizeHint(const gfx::Size& fixedSize);
  void setSizeHint(int fixedWidth, int fixedHeight);
  void resetSizeHint();

  // ===============================================================
  // MOUSE, FOCUS & KEYBOARD
  // ===============================================================

  void requestFocus();
  void releaseFocus();

  // Captures the mouse to continue receiving its messages until we
  // release the capture. Useful for widgets with painting-like
  // capabilities, where we want to keep track of the mouse until the
  // user releases the mouse button, or drag-and-drop behaviors.
  void captureMouse();
  void releaseMouse();

  // True when the widget has the keyboard focus (only widgets with
  // FOCUS_STOP flag will receive the HAS_FOCUS flag/receive the
  // focus when the user press the tab key to navigate widgets).
  bool hasFocus() const { return hasFlags(HAS_FOCUS); }

  // True when the widget has the mouse above. If the mouse leaves
  // the widget, the widget will lose the HAS_MOUSE flag. If some
  // widget captures the mouse, no other widget will have this flag,
  // so in this case there are just two options:
  //
  // 1) The widget with the capture (hasCapture()) will has the
  //    mouse flag too.
  // 2) Or no other widget will have the mouse flag until the widget
  //    releases the capture (releaseCapture())
  bool hasMouse() const { return hasFlags(HAS_MOUSE); }

  // True when the widget has captured the mouse, e.g. generally
  // when the user press a mouse button above a clickeable widget
  // (e.g. ui::Button), the widget will capture the mouse
  // temporarily until the mouse button is released. If a widget
  // captures the mouse, it will receive all mouse events until it
  // release (even if the mouse moves outside the widget).
  bool hasCapture() const { return hasFlags(HAS_CAPTURE); }

  // Returns the mouse position relative to the top-left corner of
  // the ui::Display's client area/content rect.
  gfx::Point mousePosInDisplay() const;

  // Returns the mouse position relative to the top-left cornder of
  // the widget bounds.
  gfx::Point mousePosInClientBounds() const { return toClient(mousePosInDisplay()); }

  // Offers the capture to widgets of the given type. Returns true if
  // the capture was passed to other widget.
  bool offerCapture(MouseMessage* mouseMsg, WidgetType widgetType);

  // Returns lower-case letter that represet the mnemonic of the widget
  // (the underscored character, i.e. the letter after & symbol).
  int mnemonic() const { return (m_mnemonic & kMnemonicCharMask); }
  bool mnemonicRequiresModifiers() const
  {
    return (m_mnemonic & kMnemonicModifiersMask ? true : false);
  }
  void setMnemonic(const int mnemonic, const bool requireModifiers);

  // Assigns mnemonic from the character preceded by the given
  // escapeChar ('&' by default).
  void processMnemonicFromText(const int escapeChar = '&', const bool requireModifiers = true);

  // Returns true if the mnemonic character is pressed (without modifiers).
  // TODO maybe we can add check for modifiers now that this
  //      information is included in the Widget
  bool isMnemonicPressed(const KeyMessage* keyMsg) const;

  // Returns true if the mnemonic character is pressed with
  // modifiers (Alt or Command key).
  bool isMnemonicPressedWithModifiers(const KeyMessage* msg) const;

  // Signals
  obs::signal<void()> InitTheme;
  obs::signal<void(bool)> EnabledChange;

protected:
  // ===============================================================
  // MESSAGE PROCESSING
  // ===============================================================

  virtual bool onProcessMessage(Message* msg);

  // ===============================================================
  // EVENTS
  // ===============================================================

  virtual void onInvalidateRegion(const gfx::Region& region);
  virtual void onSizeHint(SizeHintEvent& ev);
  virtual void onLoadLayout(LoadLayoutEvent& ev);
  virtual void onSaveLayout(SaveLayoutEvent& ev);
  virtual void onResize(ResizeEvent& ev);
  virtual void onPaint(PaintEvent& ev);
  virtual void onBroadcastMouseMessage(const gfx::Point& screenPos, WidgetsList& targets);
  virtual void onInitTheme(InitThemeEvent& ev);
  virtual void onSetDecorativeWidgetBounds();
  virtual void onVisible(bool visible);
  virtual void onEnable(bool enabled);
  virtual void onSelect(bool selected);
  virtual void onSetFont();
  virtual void onSetText();
  virtual void onSetBgColor();
  virtual int onGetTextInt() const;
  virtual double onGetTextDouble() const;
  virtual text::TextBlobRef onMakeTextBlob() const;
  virtual text::ShaperFeatures onGetTextShaperFeatures() const;
  virtual float onGetTextBaseline() const;

  virtual void onDragEnter(DragEvent& e);
  virtual void onDragLeave(DragEvent& e);
  virtual void onDrag(DragEvent& e);
  virtual void onDrop(DragEvent& e);

private:
  void removeChild(const WidgetsList::iterator& it);
  void paint(Graphics* graphics, const gfx::Region& drawRegion, const bool isBg);
  bool paintEvent(Graphics* graphics, const bool isBg);
  void setDirtyFlag();

  WidgetType m_type; // Widget's type
  std::string m_id;  // Widget's id
  int m_flags;       // Special boolean properties (see flags in ui/base.h)
  Theme* m_theme;    // Widget's theme
  Style* m_style;
  std::string m_text;               // Widget text
  mutable text::FontRef m_font;     // Cached font returned by the theme
  mutable text::TextBlobRef m_blob; // Cached TextBlob
  gfx::Color m_bgColor;             // Background color
  gfx::Rect m_bounds;
  gfx::Region m_updateRegion; // Region to be redrawed.
  WidgetsList m_children;     // Sub-widgets
  Widget* m_parent;           // Who is the parent?
  int m_parentIndex; // Location/index of this widget in the parent's Widget::m_children vector
  gfx::Size* m_sizeHint;

  // Keyboard shortcut to access this widget like Alt+mnemonic.  If
  // kMnemonicModifiersMask bit is zero, it means that the mnemonic
  // can be used without Alt or Command key modifiers (useful for
  // buttons in ui::Alert).
  static constexpr int kMnemonicCharMask = 0xffff;
  static constexpr int kMnemonicModifiersMask = 0x10000;
  int m_mnemonic;

  // Widget size limits
  gfx::Size m_minSize, m_maxSize;

  gfx::Border m_border; // Border separation with the parent
  int m_childSpacing;   // Separation between children
};

WidgetType register_widget_type();

} // namespace ui

#endif
