/* -*-c++-*- OpenSceneGraph - Copyright (C) 1998-2006 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.
*/


#ifndef OSGVIEWER_Keystone
#define OSGVIEWER_Keystone 1

#include <osg/Geometry>
#include <osg/Geode>
#include <osg/DisplaySettings>

#include <osgGA/GUIEventHandler>
#include <osgViewer/Export>

namespace osgViewer
{

class OSGVIEWER_EXPORT Keystone : public osg::Object
{
public:
    Keystone();

    Keystone(const Keystone& rhs, const osg::CopyOp& copop=osg::CopyOp::SHALLOW_COPY);

    META_Object(osgViewer, Keystone)

    void reset();

    Keystone& operator = (const Keystone& rhs);

    void setKeystoneEditingEnabled(bool flag) { keystoneEditingEnabled = flag; }
    bool getKeystoneEditingEnabled() const { return keystoneEditingEnabled; }

    void setGridColor(const osg::Vec4& color) { gridColour = color; }
    osg::Vec4& getGridColor() { return gridColour; }
    const osg::Vec4& getGridColor() const { return gridColour; }

    void setBottomLeft(const osg::Vec2d& v) { bottom_left = v; }
    osg::Vec2d& getBottomLeft() { return bottom_left; }
    const osg::Vec2d& getBottomLeft() const { return bottom_left; }

    void setBottomRight(const osg::Vec2d& v) { bottom_right = v; }
    osg::Vec2d& getBottomRight() { return bottom_right; }
    const osg::Vec2d& getBottomRight() const { return bottom_right; }

    void setTopLeft(const osg::Vec2d& v) { top_left = v; }
    osg::Vec2d& getTopLeft() { return top_left; }
    const osg::Vec2d& getTopLeft() const { return top_left; }

    void setTopRight(const osg::Vec2d& v) { top_right = v; }
    osg::Vec2d& getTopRight() { return top_right; }
    const osg::Vec2d& getTopRight() const { return top_right; }



    void compute3DPositions(osg::DisplaySettings* ds, osg::Vec3& tl, osg::Vec3& tr, osg::Vec3& br, osg::Vec3& bl) const;

    osg::Geode* createKeystoneDistortionMesh();

    osg::Node* createGrid();

    /** Write the file specified by the "filename" user value field. Return true if file successfully written. */
    bool writeToFile();

    /** Convenience function that loads and assigns any keystone files specified in the DisplaySettings::KeystoneFileNames list, return true if Keystone's assigned to DisplaySettings.*/
    static bool loadKeystoneFiles(osg::DisplaySettings* ds);


protected:

    bool        keystoneEditingEnabled;

    osg::Vec4   gridColour;

    osg::Vec2d  bottom_left;
    osg::Vec2d  bottom_right;
    osg::Vec2d  top_left;
    osg::Vec2d  top_right;


protected:

    virtual ~Keystone() {}


};

class OSGVIEWER_EXPORT KeystoneHandler : public osgGA::GUIEventHandler
{
public:

    KeystoneHandler(Keystone* keystone);

    ~KeystoneHandler() {}

    bool handle(const osgGA::GUIEventAdapter& ea, osgGA::GUIActionAdapter& aa, osg::Object* obj, osg::NodeVisitor* nv);

    void setKeystoneEditingEnabled(bool enabled) { if (_currentControlPoints.valid()) _currentControlPoints->setKeystoneEditingEnabled(enabled); }
    bool getKeystoneEditingEnabled() const { return _currentControlPoints.valid() ? _currentControlPoints->getKeystoneEditingEnabled() : false; }

    enum Region
    {
        NONE_SELECTED,
        TOP_LEFT,
        TOP,
        TOP_RIGHT,
        RIGHT,
        BOTTOM_RIGHT,
        BOTTOM,
        BOTTOM_LEFT,
        LEFT,
        CENTER
    };

    osg::Vec2d incrementScale(const osgGA::GUIEventAdapter& ea) const;
    Region computeRegion(const osgGA::GUIEventAdapter& ea) const;
    void move(Region region, const osg::Vec2d& delta);

protected:


    osg::ref_ptr<Keystone>              _keystone;

    osg::Vec2d                          _defaultIncrement;
    osg::Vec2d                          _ctrlIncrement;
    osg::Vec2d                          _shiftIncrement;
    osg::Vec2d                          _keyIncrement;

    osg::Vec2d                          _startPosition;
    osg::ref_ptr<Keystone>              _startControlPoints;

    Region                              _selectedRegion;
    osg::ref_ptr<Keystone>              _currentControlPoints;

};

}

#endif
