$#include "UI.h"

/// %UI subsystem. Manages the graphical user interface.
class UI : public Object
{

public:
    /// Set cursor UI element.
    void SetCursor(Cursor* cursor);
    /// Set focused UI element.
    void SetFocusElement(UIElement* element);
    /// Set modal element. Until all the modal elements are dismissed, all the inputs and events are only sent to them. Return true when successful.
    /// Only the modal element can clear its modal status or when it is being destructed.
    /// UI subystem auto-removes modal element when an ESC key is pressed, however if this is not desirable, setting a user-defined variable "NoAutoRemove" in the modal element would prevent this.
    /// In that case, the modal element will only have its modal flag reset and reparented back to its original parent.
    bool SetModalElement(UIElement* modalElement, bool enable);
    /// Clear the UI (excluding the cursor.)
    void Clear();
    /// Update the UI logic. Called by HandlePostUpdate().
    void Update(float timeStep);
    /// Update the UI for rendering. Called by HandleRenderUpdate().
    void RenderUpdate();
    /// Render the UI.
    void Render();
    /// Debug draw a UI element.
    void DebugDraw(UIElement* element);
    /// Save a UI layout to an XML file. Return true if successful.
    bool SaveLayout(Serializer& dest, UIElement* element);
    /// Set clipboard text.
    void SetClipBoardText(const String& text);
    /// Set mouse wheel handling flag.
    void SetNonFocusedMouseWheel(bool nonFocusedMouseWheel);

    /// Return root UI element.
    UIElement* GetRoot() const { return rootElement_; }
    /// Return root modal element.
    UIElement* GetRootModalElement() const { return rootModalElement_; }
    /// Return cursor.
    Cursor* GetCursor() const { return cursor_; }
    /// Return UI element at screen coordinates.
    UIElement* GetElementAt(const IntVector2& position, bool enabledOnly = true);
    /// Return UI element at screen coordinates.
    UIElement* GetElementAt(int x, int y, bool enabledOnly = true);
    /// Return focused element.
    UIElement* GetFocusElement() const { return focusElement_; }
    /// Return topmost enabled root-level non-modal element.
    UIElement* GetFrontElement() const;
    /// Return cursor position.
    IntVector2 GetCursorPosition() const;
    /// Return clipboard text.
    const String& GetClipBoardText() const { return clipBoard_; }
    /// Return mouse wheel handling flag.
    bool IsNonFocusedMouseWheel() const { return nonFocusedMouseWheel_; }
    /// Return true when UI has modal element(s).
    bool HasModalElement() const;
};