/* OpenSceneGraph example, osgvertexattributes.
*
*  Permission is hereby granted, free of charge, to any person obtaining a copy
*  of this software and associated documentation files (the "Software"), to deal
*  in the Software without restriction, including without limitation the rights
*  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
*  copies of the Software, and to permit persons to whom the Software is
*  furnished to do so, subject to the following conditions:
*
*  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
*  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
*  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
*  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
*  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
*  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
*  THE SOFTWARE.
*/

#include <osgUtil/ShaderGen>
#include <osgDB/ReadFile>
#include <osgDB/WriteFile>
#include <osgViewer/Viewer>
#include <osgViewer/ViewerEventHandlers>
#include <osgGA/TrackballManipulator>

class ConvertToVertexAttibArrays : public osg::NodeVisitor
{
    public:

        typedef std::pair<unsigned int, std::string> AttributeAlias;

        ConvertToVertexAttibArrays():
            osg::NodeVisitor(osg::NodeVisitor::TRAVERSE_ALL_CHILDREN)
        {
            _manualVertexAliasing = false;

            // mappings taken from http://www.opengl.org/registry/specs/NV/vertex_program.txt
            _vertexAlias = AttributeAlias(0, "osg_Vertex");
            _normalAlias = AttributeAlias(2, "osg_Normal");
            _colorAlias = AttributeAlias(3, "osg_Color");
            _secondaryColorAlias = AttributeAlias(4, "osg_SecondaryColor");
            _fogCoordAlias = AttributeAlias(5, "osg_FogCoord");
            _texCoordAlias[0] = AttributeAlias(8, "osg_MultiTexCoord0");
            _texCoordAlias[1] = AttributeAlias(9, "osg_MultiTexCoord1");
            _texCoordAlias[2] = AttributeAlias(10, "osg_MultiTexCoord2");
            _texCoordAlias[3] = AttributeAlias(11, "osg_MultiTexCoord3");
            _texCoordAlias[4] = AttributeAlias(12, "osg_MultiTexCoord4");
            _texCoordAlias[5] = AttributeAlias(13, "osg_MultiTexCoord5");
            _texCoordAlias[6] = AttributeAlias(14, "osg_MultiTexCoord6");
            _texCoordAlias[7] = AttributeAlias(15, "osg_MultiTexCoord7");
        }

        void bindAttribute(osg::Program& program, const AttributeAlias& alias)
        {
                program.addBindAttribLocation(alias.second, alias.first);
        }

        void replaceAndBindAttrib(osg::Program& program, std::string& source, const std::string& originalStr, const AttributeAlias& alias, const std::string& declarationPrefix)
        {
            if (replace(source, originalStr, alias.second))
            {
                source.insert(0, declarationPrefix + alias.second + std::string(";\n"));
                if (_manualVertexAliasing) bindAttribute(program, alias);
            }
        }

        void replaceBuiltInUniform(std::string& source, const std::string& originalStr, const std::string& newStr, const std::string& declarationPrefix)
        {
            if (replace(source, originalStr, newStr))
            {
                source.insert(0, declarationPrefix + newStr + std::string(";\n"));
            }
        }

        void convertVertexShader(osg::Program& program, osg::Shader& shader)
        {
            std::string source = shader.getShaderSource();

            // replace ftransform as it only works with built-ins
            replace(source, "ftransform()", "gl_ModelViewProjectionMatrix * gl_Vertex");

#if 1
            replaceAndBindAttrib(program, source, "gl_Normal", _normalAlias, "attribute vec3 ");
            replaceAndBindAttrib(program, source, "gl_Vertex", _vertexAlias, "attribute vec4 ");
            replaceAndBindAttrib(program, source, "gl_Color", _colorAlias, "attribute vec4 ");
            replaceAndBindAttrib(program, source, "gl_SecondaryColor", _secondaryColorAlias, "attribute vec4 ");
            replaceAndBindAttrib(program, source, "gl_FogCoord", _fogCoordAlias, "attribute float ");

            replaceAndBindAttrib(program, source, "gl_MultiTexCoord0", _texCoordAlias[0], "attribute vec4 ");
            replaceAndBindAttrib(program, source, "gl_MultiTexCoord1", _texCoordAlias[1], "attribute vec4 ");
            replaceAndBindAttrib(program, source, "gl_MultiTexCoord2", _texCoordAlias[2], "attribute vec4 ");
            replaceAndBindAttrib(program, source, "gl_MultiTexCoord3", _texCoordAlias[3], "attribute vec4 ");
            replaceAndBindAttrib(program, source, "gl_MultiTexCoord4", _texCoordAlias[4], "attribute vec4 ");
            replaceAndBindAttrib(program, source, "gl_MultiTexCoord5", _texCoordAlias[5], "attribute vec4 ");
            replaceAndBindAttrib(program, source, "gl_MultiTexCoord6", _texCoordAlias[6], "attribute vec4 ");
            replaceAndBindAttrib(program, source, "gl_MultiTexCoord7", _texCoordAlias[7], "attribute vec4 ");
#endif

#if 1
            // replace built in uniform
            replaceBuiltInUniform(source, "gl_ModelViewMatrix", "osg_ModeViewMatrix", "uniform mat4 ");
            replaceBuiltInUniform(source, "gl_ModelViewProjectionMatrix", "osg_ModelViewProjectionMatrix", "uniform mat4 ");
            replaceBuiltInUniform(source, "gl_ProjectionMatrix", "osg_ProjectionMatrix", "uniform mat4 ");
#endif
            shader.setShaderSource(source);
        }

        void convertFragmentShader(osg::Program& program, osg::Shader& shader)
        {
        }

        virtual void reset()
        {
            _visited.clear();
        }

        void apply(osg::Node& node)
        {
            if (_visited.count(&node)!=0) return;
            _visited.insert(&node);

            if (node.getStateSet()) apply(*(node.getStateSet()));
            traverse(node);
        }

        void apply(osg::Geode& geode)
        {
            if (_visited.count(&geode)!=0) return;
            _visited.insert(&geode);

            if (geode.getStateSet()) apply(*(geode.getStateSet()));

            for(unsigned int i=0; i<geode.getNumDrawables(); ++i)
            {
                if (geode.getDrawable(i)->getStateSet()) apply(*(geode.getDrawable(i)->getStateSet()));

                osg::Geometry* geom = geode.getDrawable(i)->asGeometry();
                if (geom) apply(*geom);
            }
        }

        bool replace(std::string& str, const std::string& original_phrase, const std::string& new_phrase)
        {
            bool replacedStr = false;
            std::string::size_type pos = 0;
            while((pos=str.find(original_phrase, pos))!=std::string::npos)
            {
                std::string::size_type endOfPhrasePos = pos+original_phrase.size();
                if (endOfPhrasePos<str.size())
                {
                    char c = str[endOfPhrasePos];
                    if ((c>='0' && c<='9') ||
                        (c>='a' && c<='z') ||
                        (c>='A' && c<='Z'))
                    {
                        pos = endOfPhrasePos;
                        continue;
                    }
                }

                replacedStr = true;
                str.replace(pos, original_phrase.size(), new_phrase);
            }
            return replacedStr;
        }

        void apply(osg::Program& program, osg::Shader& shader)
        {
             if (_visited.count(&shader)!=0) return;
            _visited.insert(&shader);

            osg::notify(osg::NOTICE)<<"Shader "<<shader.getTypename()<<" ----before-----------"<<std::endl;
            osg::notify(osg::NOTICE)<<shader.getShaderSource()<<std::endl;

            if (shader.getType()==osg::Shader::VERTEX) convertVertexShader(program, shader);
            else if (shader.getType()==osg::Shader::FRAGMENT) convertFragmentShader(program, shader);

            osg::notify(osg::NOTICE)<<"--after-----------"<<std::endl;
            osg::notify(osg::NOTICE)<<shader.getShaderSource()<<std::endl;
            osg::notify(osg::NOTICE)<<"---------------------"<<std::endl;
        }

        void apply(osg::StateSet& stateset)
        {
             if (_visited.count(&stateset)!=0) return;
            _visited.insert(&stateset);

            return;

            osg::notify(osg::NOTICE)<<"Found stateset "<<&stateset<<std::endl;
            osg::Program* program = dynamic_cast<osg::Program*>(stateset.getAttribute(osg::StateAttribute::PROGRAM));
            if (program)
            {
                osg::notify(osg::NOTICE)<<"   Found Program "<<program<<std::endl;
                for(unsigned int i=0; i<program->getNumShaders(); ++i)
                {
                    apply(*program, *(program->getShader(i)));
                }

            }
       }

        void apply(osg::Geometry& geom)
        {
            geom.setUseDisplayList(false);

            if (!_manualVertexAliasing) return;

            osg::notify(osg::NOTICE)<<"Found geometry "<<&geom<<std::endl;
            if (geom.getVertexArray())
            {
                setVertexAttrib(geom, _vertexAlias, geom.getVertexArray(), false, osg::Array::BIND_PER_VERTEX);
                geom.setVertexArray(0);
            }

            if (geom.getNormalArray())
            {
                setVertexAttrib(geom, _normalAlias, geom.getNormalArray(), true);
                geom.setNormalArray(0);
            }

            if (geom.getColorArray())
            {
                setVertexAttrib(geom, _colorAlias, geom.getColorArray(), false);
                geom.setColorArray(0);
            }

            if (geom.getSecondaryColorArray())
            {
                setVertexAttrib(geom, _secondaryColorAlias, geom.getSecondaryColorArray(), false);
                geom.setSecondaryColorArray(0);
            }

            if (geom.getFogCoordArray())
            {
                // should we normalize the FogCoord array? Don't think so...
                setVertexAttrib(geom, _fogCoordAlias, geom.getFogCoordArray(), false);
                geom.setFogCoordArray(0);
            }

            unsigned int maxNumTexCoords = geom.getNumTexCoordArrays();
            if (maxNumTexCoords>8)
            {
                osg::notify(osg::NOTICE)<<"Warning: Ignoring "<<maxNumTexCoords-8<<" texture coordinate arrays, only 8 are currently supported in vertex attribute conversion code."<<std::endl;
                maxNumTexCoords = 8;
            }
            for(unsigned int i=0; i<maxNumTexCoords; ++i)
            {
                if (geom.getTexCoordArray(i))
                {
                    setVertexAttrib(geom, _texCoordAlias[i], geom.getTexCoordArray(i), false, osg::Array::BIND_PER_VERTEX);
                    geom.setTexCoordArray(i,0);
                }
                else
                {
                    osg::notify(osg::NOTICE)<<"Found empty TexCoordArray("<<i<<")"<<std::endl;
                }
            }
        }

        void setVertexAttrib(osg::Geometry& geom, const AttributeAlias& alias, osg::Array* array, bool normalize, osg::Array::Binding binding = osg::Array::BIND_UNDEFINED)
        {
            unsigned int index = alias.first;
            const std::string& name = alias.second;
            array->setName(name);
            if (binding!=osg::Array::BIND_UNDEFINED) array->setBinding(binding);
            array->setNormalize(normalize);
            geom.setVertexAttribArray(index, array);

            osg::notify(osg::NOTICE)<<"   vertex attrib("<<name<<", index="<<index<<", normalize="<<normalize<<" binding="<<binding<<")"<<std::endl;
        }


        typedef std::set<osg::Object*> Visited;
        Visited         _visited;

        bool           _manualVertexAliasing;
        AttributeAlias _vertexAlias;
        AttributeAlias _normalAlias;
        AttributeAlias _colorAlias;
        AttributeAlias _secondaryColorAlias;
        AttributeAlias _fogCoordAlias;
        AttributeAlias _texCoordAlias[8];
};

osg::Node* createSimpleTestModel()
{
    osg::Group* group = new osg::Group;

    osg::Geode* geode = new osg::Geode;
    group->addChild(geode);

    osg::Geometry* geometry = new osg::Geometry;
    geode->addDrawable(geometry);

    osg::Vec3Array* vertices = new osg::Vec3Array;
    vertices->push_back(osg::Vec3(0.0,0.0,0.0));
    vertices->push_back(osg::Vec3(0.0,0.0,1.0));
    vertices->push_back(osg::Vec3(1.0,0.0,0.0));
    vertices->push_back(osg::Vec3(1.0,0.0,1.0));
    geometry->setVertexArray(vertices);

    geometry->addPrimitiveSet(new osg::DrawArrays(GL_TRIANGLE_STRIP, 0, 4));

    char vertexShaderSource[] =
       "void main(void)\n"
       "{\n"
       "    gl_Position = gl_ModelViewProjectionMatrix * gl_Vertex;\n"
       "}\n";

    char fragmentShaderSource[] =
        "void main(void)\n"
        "{\n"
        "    gl_FragColor = vec4(1.0,1.0,0.0,1.0); \n"
        "}\n";

    osg::Program* program = new osg::Program;
    program->addShader(new osg::Shader(osg::Shader::VERTEX, vertexShaderSource));
    program->addShader(new osg::Shader(osg::Shader::FRAGMENT, fragmentShaderSource));

    geometry->getOrCreateStateSet()->setAttribute(program);

    return group;
}

osg::Node* createSimpleTextureTestModel()
{
    osg::Group* group = new osg::Group;

    osg::Geode* geode = new osg::Geode;
    group->addChild(geode);

    osg::Geometry* geometry = new osg::Geometry;
    geode->addDrawable(geometry);

    osg::Vec3Array* vertices = new osg::Vec3Array;
    vertices->push_back(osg::Vec3(0.0,0.0,0.0));
    vertices->push_back(osg::Vec3(0.0,0.0,1.0));
    vertices->push_back(osg::Vec3(1.0,0.0,0.0));
    vertices->push_back(osg::Vec3(1.0,0.0,1.0));
    geometry->setVertexArray(vertices);

    osg::Vec2Array* texcoords = new osg::Vec2Array;
    texcoords->push_back(osg::Vec2(0.0,0.0));
    texcoords->push_back(osg::Vec2(0.0,1.0));
    texcoords->push_back(osg::Vec2(1.0,0.0));
    texcoords->push_back(osg::Vec2(1.0,1.0));
    geometry->setTexCoordArray(0, texcoords);

    geometry->addPrimitiveSet(new osg::DrawArrays(GL_TRIANGLE_STRIP, 0, 4));

    char vertexShaderSource[] =
       "varying vec2 texCoord;\n"
       "void main(void)\n"
       "{\n"
       "    gl_Position = gl_ModelViewProjectionMatrix * gl_Vertex;\n"
       "    texCoord = gl_MultiTexCoord0.xy;\n"
       "}\n";

    char fragmentShaderSource[] =
        "varying vec2 texCoord;\n"
        "uniform sampler2D baseTexture;\n"
        "void main(void)\n"
        "{\n"
        "    gl_FragColor = texture2D(baseTexture, texCoord); \n"
        "}\n";

    osg::Program* program = new osg::Program;
    program->addShader(new osg::Shader(osg::Shader::VERTEX, vertexShaderSource));
    program->addShader(new osg::Shader(osg::Shader::FRAGMENT, fragmentShaderSource));

    osg::StateSet* stateset = geometry->getOrCreateStateSet();
    stateset->setAttribute(program);

    osg::ref_ptr<osg::Image> image = osgDB::readRefImageFile("Images/lz.rgb");
    osg::Texture2D* texture = new osg::Texture2D(image);
    texture->setFilter(osg::Texture::MIN_FILTER, osg::Texture::LINEAR);
    texture->setFilter(osg::Texture::MAG_FILTER, osg::Texture::LINEAR);
    stateset->setTextureAttribute(0, texture);

    osg::Uniform* baseTextureSampler = new osg::Uniform("baseTexture",0);
    stateset->addUniform(baseTextureSampler);

    return group;
}

int main(int argc, char *argv[])
{
    // use an ArgumentParser object to manage the program arguments.
    osg::ArgumentParser arguments(&argc,argv);

    // construct the viewer.
    osgViewer::Viewer viewer(arguments);

    std::string outputFileName;
    while (arguments.read("-o",outputFileName)) {}

    osg::ref_ptr<osg::Node> loadedModel;

    bool runConvertToVertexAttributes = false;
    if (arguments.read("--simple") || arguments.read("--s"))
    {
        loadedModel = createSimpleTestModel();
    }
    else if (arguments.read("--texture") || arguments.read("-t"))
    {
        loadedModel = createSimpleTextureTestModel();
    }
    else
    {
        bool runShaderGen = true;
        while (arguments.read("--shader-gen")) { runShaderGen = true; }
        while (arguments.read("--no-shader-gen")) { runShaderGen = false; }

        while (arguments.read("--vertex-attrib")) { runConvertToVertexAttributes = true; }
        while (arguments.read("--no-vertex-attrib")) { runConvertToVertexAttributes = false; }

        loadedModel = osgDB::readRefNodeFiles(arguments);
        if (!loadedModel.get())
        {
            osg::notify(osg::NOTICE)<<"No model loaded, please specify a model filename."<<std::endl;
            return 1;
        }

        if (runShaderGen)
        {
            // convert fixed function pipeline to shaders
            osgUtil::ShaderGenVisitor sgv;
            loadedModel->accept(sgv);
        }

        if (runConvertToVertexAttributes)
        {
            // find any conventional vertex, colour, normal and tex coords arrays and convert to vertex attributes
            ConvertToVertexAttibArrays ctvaa;
            loadedModel->accept(ctvaa);
        }
    }

    if (!loadedModel) return 1;

    if (!outputFileName.empty())
    {
        osgDB::writeNodeFile(*loadedModel, outputFileName);
        return 0;
    }

    // add a viewport to the viewer and attach the scene graph.
    viewer.setSceneData(loadedModel);

    viewer.setCameraManipulator(new osgGA::TrackballManipulator());

    // add the stats handler
    viewer.addEventHandler(new osgViewer::StatsHandler);

    viewer.realize();


    if (runConvertToVertexAttributes)
    {
        // switch on the uniforms that track the modelview and projection matrices
        osgViewer::Viewer::Windows windows;
        viewer.getWindows(windows);
        for(osgViewer::Viewer::Windows::iterator itr = windows.begin();
            itr != windows.end();
            ++itr)
        {
            (*itr)->getState()->setUseModelViewAndProjectionUniforms(true);
            (*itr)->getState()->setUseVertexAttributeAliasing(true);
        }
    }

    return viewer.run();
}