#include <cstdlib>
#include <sstream>
#include <osg/io_utils>
#include <osg/ArgumentParser>
#include <osg/Geode>
#include <osgViewer/Viewer>
#include <osgViewer/ViewerEventHandlers>
#include <osgGA/StateSetManipulator>

void textInfo(osgText::Text* text)
{
    const osgText::Text::TextureGlyphQuadMap& tgqm = text->getTextureGlyphQuadMap();

    const osgText::Text::TextureGlyphQuadMap::const_iterator tgqmi = tgqm.begin();

    const osgText::Text::GlyphQuads& gq = tgqmi->second;

    osgText::String& s = text->getText();

    for(unsigned int i = 0; i < s.size(); i++)
    {
        osg::Vec2 ul = (*gq.getCoords())[0 + (i * 4)]; // upperLeft
        osg::Vec2 ll = (*gq.getCoords())[1 + (i * 4)]; // lowerLeft
        osg::Vec2 lr = (*gq.getCoords())[2 + (i * 4)]; // lowerRight
        osg::Vec2 ur = (*gq.getCoords())[3 + (i * 4)]; // upperRight

        osg::notify(osg::NOTICE)
            << "'" << static_cast<char>(s[i]) << "':"
            << " width(" << lr.x() - ll.x() << ")"
            << " height(" << ul.y() - ll.y() << ")" << std::endl << "\t"
            << "ul(" << ul << "), "
            << "ll(" << ll << "), "
            << "lr(" << lr << "), "
            << "ur(" << ur << ")"
            << std::endl
        ;
    }
}

osg::Camera* createOrthoCamera(double width, double height)
{
    osg::Camera* camera = new osg::Camera();

    camera->getOrCreateStateSet()->setMode(
        GL_LIGHTING,
        osg::StateAttribute::PROTECTED | osg::StateAttribute::OFF
    );

    osg::Matrix m = osg::Matrix::ortho2D(0.0f, width, 0.0f, height);

    camera->setProjectionMatrix(m);
    camera->setReferenceFrame(osg::Transform::ABSOLUTE_RF);
    camera->setViewMatrix(osg::Matrix::identity());
    camera->setClearMask(GL_DEPTH_BUFFER_BIT);
    camera->setRenderOrder(osg::Camera::POST_RENDER);

    return camera;
}

osgText::Text* createLabel(const std::string& l, const char* f, unsigned int size)
{
    static osg::Vec3 pos(10.0f, 10.0f, 0.0f);

    osgText::Text* label = new osgText::Text();
    osg::ref_ptr<osgText::Font> font  = osgText::readRefFontFile(f);

    label->setFont(font);
    label->setCharacterSize(size);
    label->setFontResolution(size, size);
    label->setColor(osg::Vec4(1.0f, 1.0f, 1.0f, 1.0f));
    label->setPosition(pos);
    label->setAlignment(osgText::Text::LEFT_BOTTOM);

    // It seems to be important we do this last to get best results?
    label->setText(l);

    textInfo(label);

    pos.y() += size + 10.0f;

    return label;
}

typedef std::list<unsigned int> Sizes;

int main(int argc, char** argv)
{
    osgViewer::Viewer   viewer;
    osg::ArgumentParser args(&argc, argv);

    // Make sure we have the minimum args...
    if(argc <= 2)
    {
        osg::notify(osg::FATAL) << "usage: " << args[0] << " fontfile size1 [size2 ...]" << std::endl;

        return 1;
    }


    viewer.addEventHandler( new osgGA::StateSetManipulator(viewer.getCamera()->getOrCreateStateSet()) );
    viewer.addEventHandler(new osgViewer::StatsHandler());
    viewer.addEventHandler(new osgViewer::WindowSizeHandler());

    osg::Group*  group  = new osg::Group();
    osg::Camera* camera = createOrthoCamera(1280.0f, 1024.0f);

    // Create the list of desired sizes.
    Sizes sizes;

    for(int i = 2; i < argc; i++)
    {
        if(!args.isNumber(i)) continue;

        sizes.push_back(std::atoi(args[i]));
    }

    osg::Geode* geode = new osg::Geode();

    // Add all of our osgText drawables.
    for(Sizes::const_iterator i = sizes.begin(); i != sizes.end(); i++)
    {
        std::stringstream ss;

        ss << *i << " 1234567890 abcdefghijklmnopqrstuvwxyz ABCDEFGHIJKLMNOPQRSTUVWXYZ";

        geode->addDrawable(createLabel(ss.str(), args[1], *i));
    }

    camera->addChild(geode);

    group->addChild(camera);

    viewer.setSceneData(group);

    return viewer.run();
}