/*      _______   __   __   __   ______   __   __   _______   __   __
 *     / _____/\ / /\ / /\ / /\ / ____/\ / /\ / /\ / ___  /\ /  |\/ /\
 *    / /\____\// / // / // / // /\___\// /_// / // /\_/ / // , |/ / /
 *   / / /__   / / // / // / // / /    / ___  / // ___  / // /| ' / /
 *  / /_// /\ / /_// / // / // /_/_   / / // / // /\_/ / // / |  / /
 * /______/ //______/ //_/ //_____/\ /_/ //_/ //_/ //_/ //_/ /|_/ /
 * \______\/ \______\/ \_\/ \_____\/ \_\/ \_\/ \_\/ \_\/ \_\/ \_\/
 *
 * Copyright (c) 2004, 2005, 2006, 2007 Olof Naessén and Per Larsson
 *
 *                                                         Js_./
 * Per Larsson a.k.a finalman                          _RqZ{a<^_aa
 * Olof Naessén a.k.a jansem/yakslem                _asww7!uY`>  )\a//
 *                                                 _Qhm`] _f "'c  1!5m
 * Visit: http://guichan.darkbits.org             )Qk<P ` _: :+' .'  "{[
 *                                               .)j(] .d_/ '-(  P .   S
 * License: (BSD)                                <Td/Z <fP"5(\"??"\a.  .L
 * Redistribution and use in source and          _dV>ws?a-?'      ._/L  #'
 * binary forms, with or without                 )4d[#7r, .   '     )d`)[
 * modification, are permitted provided         _Q-5'5W..j/?'   -?!\)cam'
 * that the following conditions are met:       j<<WP+k/);.        _W=j f
 * 1. Redistributions of source code must       .$%w\/]Q  . ."'  .  mj$
 *    retain the above copyright notice,        ]E.pYY(Q]>.   a     J@\
 *    this list of conditions and the           j(]1u<sE"L,. .   ./^ ]{a
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 * 2. Redistributions in binary form must        )_]X{Z('a_"a7'<a"a,  ]"[
 *    reproduce the above copyright notice,       #}<]m7`Za??4,P-"'7. ).m
 *    this list of conditions and the            ]d2e)Q(<Q(  ?94   b-  LQ/
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 *    documentation and/or other materials      .Z!=J ]e []('-4f _ ) -.)m]'
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 * 3. Neither the name of Guichan nor the      :$we` _! + _/ .        j?
 *    names of its contributors may be used     =3)= _f  (_yQmWW$#(    "
 *    to endorse or promote products derived     -   W,  sQQQQmZQ#Wwa]..
 *    from this software without specific        (js, \[QQW$QWW#?!V"".
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 *                                                 -]n w/ '         [.
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT       )/ )/           !
 * HOLDERS AND CONTRIBUTORS "AS IS" AND ANY         <  (; sac    ,    '
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 * BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF            c <   r
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 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR        _bQf` y`..)a
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 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES               _Pa,)!f/<[]/  ?"
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 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION)                     ^
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
 * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN
 * IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#ifndef GCN_FOCUSHANDLER_HPP
#define GCN_FOCUSHANDLER_HPP

#include <vector>

#include "guisan/event.hpp"
#include "guisan/platform.hpp"

namespace gcn
{
	class Widget;

	/**
	 * Used to keep track of widget focus. You will probably not have
	 * to use the FocusHandler directly to handle focus. Widget has
	 * functions for handling focus which uses a FocusHandler. Use them
	 * instead.
	 *
	 * @see Widget::isFocused
	 * @see Widget::requestFocus
	 * @see Widget::setFocusable
	 * @see Widget::isFocusable
	 * @see FocusListener
	 */
	class GCN_CORE_DECLSPEC FocusHandler
	{
	public:

		/**
		 * Constructor.
		 */
		FocusHandler();

		/**
		 * Destructor.
		 */
		virtual ~FocusHandler()
		= default;;

		/**
		 * Sets focus to a widget. A focus event will also be sent to the widget's
		 * focus listeners.
		 *
		 * @param widget the widget to focus.
		 */
		virtual void requestFocus(Widget* widget);

		/**
		 * Sets modal focus to a widget.
		 *
		 * @param widget the Widget to focus modal.
		 * @throws Exception when another widget already has modal focus.
		 */
		virtual void requestModalFocus(Widget* widget);

		/**
		 * Releases modal focus if the widget has modal focus.
		 * Otherwise nothing will be done.
		 *
		 * @param widget the Widget to release modal focus for.
		 */
		virtual void releaseModalFocus(Widget* widget);

		/**
		 * Sets modal mouse input focus to a widget. Modal mouse input focus means
		 * no other widget then the widget with modal mouse input focus will
		 * receive mouse input..
		 * The widget with modal mouse input focus will also receive mouse input no
		 * matter what the mouse input is or where the mouse input occurs.
		 *
		 * @param widget the widget to focus for modal mouse input focus.
		 * @throws Exception when another widget already has modal mouse input focus.
		 */
		virtual void requestModalMouseInputFocus(Widget* widget);

		/**
		 * Releases modal mouse input focus if the widget has modal mouse input
		 * focus. Otherwise nothing will be done.
		 *
		 * @param widget the widget to release modal mouse input focus for.
		 */
		virtual void releaseModalMouseInputFocus(Widget* widget);

		/**
		 * Gets the widget with focus.
		 *
		 * @return the Widget with focus. NULL will be returned if
		 *         no Widget has focus.
		 */
		[[nodiscard]] virtual Widget* getFocused() const;

		/**
		 * Gets the widget with modal focus.
		 *
		 * @return the Widget with modal focus. NULL will be returned
		 *         if no Widget has modal focus.
		 */
		[[nodiscard]] virtual Widget* getModalFocused() const;

		/**
		 * Gets the widget with modal mouse input focus.
		 *
		 * @return the widget with modal mouse input focus. NULL will be returned
		 *         if no widget has modal mouse input focus.
		 */
		[[nodiscard]] virtual Widget* getModalMouseInputFocused() const;

		/**
		 * Focuses the next Widget. If no Widget has focus the first
		 * Widget gets focus. The order in which the Widgets are focused
		 * depends on the order you add them to the GUI.
		 */
		virtual void focusNext();

		/**
		 * Focuses the previous Widget. If no Widget has focus the first
		 * Widget gets focus. The order in which the widgets are focused
		 * depends on the order you add them to the GUI.
		 */
		virtual void focusPrevious();

		/**
		 * Checks if a Widget is focused.
		 *
		 * @param widget widget to check if it is focused.
		 * @return true if the widget is focused.
		 */
		virtual bool isFocused(const Widget* widget) const;

		/**
		 * Adds a widget to the FocusHandler.
		 *
		 * @param widget the widget to add.
		 */
		virtual void add(Widget* widget);

		/**
		 * Removes a widget from the FocusHandler.
		 *
		 * @param widget the widget to remove.
		 */
		virtual void remove(Widget* widget);

		/**
		 * Focuses nothing. A focus event will also be sent to the focused widget's
		 * focus listeners if a widget has focus.
		 */
		virtual void focusNone();

		/**
		 * Focuses the next Widget which allows tab in unless current focused
		 * Widget disallows tab out.
		 */
		virtual void tabNext();

		/**
		 * Focuses the previous Widget which allows tab in unless current focused
		 * Widget disallows tab out.
		 */
		virtual void tabPrevious();

		/**
		 * Gets the widget being dragged.
		 * 
		 * @return the widget being dragged.
		 */
		virtual Widget* getDraggedWidget();

		/**
		 * Sets the widget being dragged.
		 * 
		 * @param draggedWidget the widget being dragged.
		 */
		virtual void setDraggedWidget(Widget* draggedWidget);

		/**
		 * Gets the last widget with the mouse.
		 * 
		 * @return the last widget with the mouse.
		 */
		virtual Widget* getLastWidgetWithMouse();

		/**
		 * Sets the last widget with the mouse.
		 *
		 * @param lastWidgetWithMouse the last widget with the mouse.
		 */
		virtual void setLastWidgetWithMouse(Widget* lastWidgetWithMouse);

		/**
		 * Gets the last widget with modal focus.
		 * 
		 * @return the last widget with modal focus.
		 */
		virtual Widget* getLastWidgetWithModalFocus();

		/**
		 * Sets the last widget with modal focus.
		 * 
		 * @param lastWidgetWithModalFocus the last widget with modal focus.
		 */
		virtual void setLastWidgetWithModalFocus(Widget* lastWidgetWithModalFocus);

		/**
		 * Gets the last widget with modal mouse input focus.
		 *
		 * @return the last widget with modal mouse input focus.
		 */
		virtual Widget* getLastWidgetWithModalMouseInputFocus();

		/**
		 * Sets the last widget with modal mouse input focus.
		 *
		 * @param lastWidgetWithModalMouseInputFocus  the last widget with modal mouse input focus.
		 */
		virtual void setLastWidgetWithModalMouseInputFocus(Widget* lastWidgetWithModalMouseInputFocus);

		/**
		 * Gets the last widget pressed.
		 *
		 * @return the last widget pressed. 
		 */
		virtual Widget* getLastWidgetPressed();

		/**
		 * Sets the last widget pressed.
		 *
		 * @param lastWidgetPressed the last widget pressed.
		 */
		virtual void setLastWidgetPressed(Widget* lastWidgetPressed);

	protected:
		/**
		 * Distributes a focus lost event.
		 *
		 * @param focusEvent the event to distribute.
		 * @author Olof Naessén
		 * @since 0.7.0
		 */
		virtual void distributeFocusLostEvent(const Event& focusEvent);

		/**
		 * Distributes a focus gained event.
		 *
		 * @param focusEvent the event to distribute.
		 * @author Olof Naessén
		 * @since 0.7.0
		 */
		virtual void distributeFocusGainedEvent(const Event& focusEvent);

		typedef std::vector<Widget*> WidgetVector;
		typedef WidgetVector::iterator WidgetIterator;
		WidgetVector mWidgets;

		Widget* mFocusedWidget;
		Widget* mModalFocusedWidget;
		Widget* mModalMouseInputFocusedWidget;

		Widget* mDraggedWidget;
		Widget* mLastWidgetWithMouse;
		Widget* mLastWidgetWithModalFocus;
		Widget* mLastWidgetWithModalMouseInputFocus;
		Widget* mLastWidgetPressed;
	};
}

#endif // end GCN_FOCUSHANDLER_HPP