/* -*-c++-*- OpenSceneGraph - Copyright (C) 1998-2008 Robert Osfield
 *
 * This library is open source and may be redistributed and/or modified under
 * the terms of the OpenSceneGraph Public License (OSGPL) version 0.0 or
 * (at your option) any later version.  The full license is in LICENSE file
 * included with this distribution, and on the openscenegraph.org website.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * OpenSceneGraph Public License for more details.
*/

// Code by: Jeremy Moles (cubicool) 2007-2008

#ifndef OSGWIDGET_WINDOW_MANAGER
#define OSGWIDGET_WINDOW_MANAGER

#include <osg/Switch>
#include <osg/Uniform>
#include <osg/Drawable>
#include <osgGA/GUIEventAdapter>
#include <osgUtil/LineSegmentIntersector>
#include <osgViewer/View>
#include <osgWidget/ScriptEngine>
#include <osgWidget/StyleManager>
#include <osgWidget/Window>

namespace osgWidget {

// TODO: It should be possible to use something other than osgWidget/ViewerEventHandlers
// to handle all of these events. In fact, I need to create an SDL example showing this.

// A private typedef that we use for pickAtXY() below.
typedef osgUtil::LineSegmentIntersector::Intersections Intersections;

// A WindowManager performs pointer interaction with the topmost (highest Z) Widget,
// and performs keyboard input on the currently focused Window->Widget.
class OSGWIDGET_EXPORT WindowManager: public osg::Switch, public UIObjectParent<Window> {
    public:
        enum WmFlags {
            WM_USE_LUA        = 0x00000001,
            WM_USE_PYTHON     = 0x00000002,
            WM_USE_RENDERBINS = 0x00000004,
            WM_PICK_DEBUG     = 0x00000008
        };

        enum PointerDirection {
            PD_NONE  = 0x00000000,
            PD_LEFT  = 0x00000001,
            PD_RIGHT = 0x00000002,
            PD_UP    = 0x00000004,
            PD_DOWN  = 0x00000008
        };

        enum PointerFocusMode {
            PFM_FOCUS   = 0x00000000,
            PFM_UNFOCUS = 0x00000001,
            PFM_SLOPPY  = 0x00000002
        };

    public:
        META_Object(osgWidget, WindowManager);

        WindowManager(
            osgViewer::View* = 0,
            point_type       = 0.0f,
            point_type       = 0.0f,
            unsigned int     = 0,
            unsigned int     = 0
        );

        WindowManager(const WindowManager&, const osg::CopyOp&);

        virtual ~WindowManager();

        // A static method that will set both the _widget and _window data of an Event
        // reference from a passed-in Interface.
        static void setEventFromInterface(Event&, EventInterface*);

        // A static template method that will iterate over a container and return a
        // properly formed EventInterface*.
        template<typename T>
        static EventInterface* getFirstEventInterface(T&, Event&);

        bool pickAtXY         (float, float, WidgetList&);
        bool setFocused       (Window*);
        void setPointerXY     (float, float);
        void setStyleManager  (StyleManager*);
        void resizeAllWindows (bool = true);

        XYCoord windowXY (double, double) const;
        XYCoord localXY  (double, double) const;

        // Methods all called by the ViewerEventHandlers::MouseHandler object, or
        // by some customer caller of your own. Examples of this to come...
        bool pointerMove (float, float);
        bool pointerDrag (float, float);
        bool mouseScroll (float, float);

        osg::Camera* createParentOrthoCamera();

        unsigned int getNodeMask() const {
            return _nodeMask;
        }

        point_type getWidth() const {
            return _width;
        }

        point_type getHeight() const {
            return _height;
        }

        bool isUsingLua() const {
            return (_flags & WM_USE_LUA) != 0;
        }

        bool isUsingPython() const {
            return (_flags & WM_USE_PYTHON) != 0;
        }

        bool isUsingRenderBins() const {
            return (_flags & WM_USE_RENDERBINS) != 0;
        }

        int getMouseKeysDown() const {
            int flag = 0;

            flag |= _leftDown ? osgGA::GUIEventAdapter::LEFT_MOUSE_BUTTON : 0;
            flag |= _middleDown ? osgGA::GUIEventAdapter::MIDDLE_MOUSE_BUTTON: 0;
            flag |= _rightDown ? osgGA::GUIEventAdapter::RIGHT_MOUSE_BUTTON : 0;

            return flag;
        }

        ScriptEngine* getLuaEngine() {
            return _lua.get();
        }

        const ScriptEngine* getLuaEngine() const {
            return _lua.get();
        }

        ScriptEngine* getPythonEngine() {
            return _python.get();
        }

        const ScriptEngine* getPythonEngine() const {
            return _python.get();
        }

        StyleManager* getStyleManager() {
            return _styleManager.get();
        }

        const StyleManager* getStyleManager() const {
            return _styleManager.get();
        }

        PointerDirection getPointerVerticalDirection() const {
            return _lastVertical;
        }

        PointerDirection getPointerHorizontalDirection() const {
            return _lastHorizontal;
        }

        PointerFocusMode getPointerFocusMode() const {
            return _focusMode;
        }

        int getPointerDirectionVector() const {
            return _lastVertical | _lastHorizontal;
        }

        bool isPointerMovingUp() const {
            return _lastVertical == PD_UP;
        }

        bool isPointerMovingDown() const {
            return _lastVertical == PD_DOWN;
        }

        bool isPointerMovingLeft() const {
            return _lastHorizontal == PD_LEFT;
        }

        bool isPointerMovingRight() const {
            return _lastHorizontal == PD_RIGHT;
        }

        bool isPointerMovingVertically() const {
            return _lastVertical != PD_NONE;
        }

        bool isPointerMovingHorizontally() const {
            return _lastHorizontal != PD_NONE;
        }

        bool isLeftMouseButtonDown() const {
            return _leftDown;
        }

        bool isMiddleMouseButtonDown() const {
            return _middleDown;
        }

        bool isRightMouseButtonDown() const {
            return _rightDown;
        }

        bool isMouseScrollingUp() const {
            return _scrolling == osgGA::GUIEventAdapter::SCROLL_UP;
        }

        bool isMouseScrollingDown() const {
            return _scrolling == osgGA::GUIEventAdapter::SCROLL_DOWN;
        }

        bool setFocusedByName(const std::string& name) {
            return setFocused(getByName(name));
        }

        void setScrollingMotion(osgGA::GUIEventAdapter::ScrollingMotion sm) {
            _scrolling = sm;
        }

        void setPointerFocusMode(PointerFocusMode pfm) {
            _focusMode = pfm;
        }

        void setWidth(point_type w) {
            _width = w;
        }

        void setHeight(point_type h) {
            _height = h;
        }

        void setSize(point_type w, point_type h) {
            _width  = w;
            _height = h;
        }

        void setWindowSize(point_type w, point_type h) {
            _windowWidth  = w;
            _windowHeight = h;
        }

        // Wrappers around the real calls. These only pertains to mouse buttons,
        // particularly 3-button mice, although there are other more generic
        // "pointer" API methods.
        bool mousePushedLeft(float x, float y) {
            return _handleMousePushed(x, y, _leftDown);
        }

        bool mousePushedMiddle(float x, float y) {
            return _handleMousePushed(x, y, _middleDown);
        }

        bool mousePushedRight(float x, float y) {
            return _handleMousePushed(x, y, _rightDown);
        }

        bool mouseReleasedLeft(float x, float y) {
            return _handleMouseReleased(x, y, _leftDown);
        }

        bool mouseReleasedMiddle(float x, float y) {
            return _handleMouseReleased(x, y, _middleDown);
        }

        bool mouseReleasedRight(float x, float y) {
            return _handleMouseReleased(x, y, _rightDown);
        }

        // Keyboards wrappers, as above; takes the key and key's mask code, which
        // can be compared to osgGA::GUIEventAdapter::{KeySymbol,KeyModMask}.
        bool keyDown (int, int);
        bool keyUp   (int, int);
        
        osgViewer::View* getView() { return _view; }
        const osgViewer::View* getView() const { return _view; }

    private:
        // A functor used to sort the Windows by their Z component in descending order.
        struct WindowZCompare: public std::binary_function<ptr_type, ptr_type, bool> {
            bool operator()(const ptr_type& x, const ptr_type& y) {
                return x.get()->getZ() > y.get()->getZ();
            }
        };

        // A functor used to sort the Windows by their BinNum component in descending order.
        struct WindowBinNumberCompare: public std::binary_function<ptr_type, ptr_type, bool> {
            bool operator()(const ptr_type& x, const ptr_type& y) {
                return
                    x.get()->getOrCreateStateSet()->getBinNumber() >
                    y.get()->getOrCreateStateSet()->getBinNumber()
                ;
            }
        };

        point_type         _width;
        point_type         _height;
        point_type         _windowWidth;
        point_type         _windowHeight;
        unsigned int       _flags;
        unsigned int       _nodeMask;
        osgViewer::View*   _view;
        float              _lastX;
        float              _lastY;
        EventInterface*    _lastEvent;
        EventInterface*    _lastPush;
        PointerDirection   _lastVertical;
        PointerDirection   _lastHorizontal;
        PointerFocusMode   _focusMode;
        bool               _leftDown;
        bool               _middleDown;
        bool               _rightDown;

        osgGA::GUIEventAdapter::ScrollingMotion _scrolling;

        osg::ref_ptr<ScriptEngine> _lua;
        osg::ref_ptr<ScriptEngine> _python;
        osg::ref_ptr<StyleManager> _styleManager;

        osg::observer_ptr<Widget> _widget;
        osg::observer_ptr<Window> _focused;
        osg::observer_ptr<Window> _pickWindow;

        void childInserted (unsigned int);
        void childRemoved  (unsigned int, unsigned int);

        bool _handleMousePushed   (float, float, bool&);
        bool _handleMouseReleased (float, float, bool&);
        bool _handleMouseScrolled (float, float, bool = false);
        void _getPointerXYDiff    (float&, float&);
        void _updatePickWindow    (const WidgetList*, point_type, point_type);

};

// We use a template here because the container could be a list or a vector; or something
// else that supports iteration!
template<typename T>
EventInterface* WindowManager::getFirstEventInterface(T& container, Event& ev) {
    if(!container.size()) return 0;

    // See if we can find a Widget that responds to this event...
    for(typename T::iterator i = container.begin(); i != container.end(); i++) {
        Widget* widget = i->get();

        // If so, set the _widget/_window members and return it.
        if(widget->getEventMask() & ev.type) {
            ev._window = widget->getParent();
            ev._widget = widget;

            return widget;
        }
    }

    // If we can't find a Widget that will accept this event, try and recurse all
    // of the parent Windows and find one that can.
    WindowList windowList;

    Window* parent = container.back()->getParent();

    if(parent) {
        parent->getParentList(windowList);

        // A WindowList from getParentList includes the Window the method was called
        // on, and the entire tree of parentage.
        for(WindowList::iterator i = windowList.begin(); i != windowList.end(); i++) {
            Window* window = i->get();

            if(window->getEventMask() & ev.type) {
                ev._window = window;

                return window;
            }
        }
    }

    return 0;
}

}

#endif