/* -*-c++-*- OpenSceneGraph - Copyright (C) 1998-2003 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.
*/

#include <osgText/Font>
#include <osgText/Text>

#include <osg/State>
#include <osg/Notify>
#include <osgDB/ReadFile>
#include <osgDB/FileUtils>
#include <osg/GLU>

using namespace osgText;
using namespace std;

std::string findFontFile(const std::string& str)
{
    // try looking in OSGFILEPATH etc first for fonts.
    std::string filename = osgDB::findDataFile(str);
    if (!filename.empty()) return std::string(filename);


    static osgDB::FilePathList s_FontFilePath;
    static bool initialized = false;
    if (!initialized)
    {
        initialized = true;
    #if defined(WIN32)
        osgDB::Registry::convertStringPathIntoFilePathList(
            ".;C:/winnt/fonts;C:/windows/fonts",
            s_FontFilePath);

        char *ptr;
        if ((ptr = getenv( "windir" )))
        {
            s_FontFilePath.push_back(ptr);
        }
    #else
        osgDB::Registry::convertStringPathIntoFilePathList(
            ".:/usr/share/fonts/ttf:/usr/share/fonts/ttf/western:/usr/share/fonts/ttf/decoratives",
            s_FontFilePath);
    #endif
    }

    filename = osgDB::findFileInPath(str,s_FontFilePath);
    if (!filename.empty()) return filename;

    osg::notify(osg::WARN)<<"Warning: font file \""<<str<<"\" not found."<<std::endl;    
    return std::string();
}

osgText::Font* osgText::readFontFile(const std::string& filename)
{
    std::string foundFile = findFontFile(filename);
    if (foundFile.empty()) return 0;

    osg::Object* object = osgDB::readObjectFile(foundFile,true);

    // if the object is a font then return it.
    osgText::Font* font = dynamic_cast<osgText::Font*>(object);
    if (font) return font;

    // otherwise if the object has zero references then delete it by doing another unref().
    if (object && object->referenceCount()==0) object->unref();
    return 0;
}


Font::Font(FontImplementation* implementation):
    _width(16),
    _height(16),
    _margin(2),
    _textureWidthHint(256),
    _textureHeightHint(256),
    _minFilterHint(osg::Texture::LINEAR_MIPMAP_LINEAR),
    _magFilterHint(osg::Texture::LINEAR)
{
    setImplementation(implementation);
}

Font::~Font()
{
    if (_implementation.valid()) _implementation->_facade = 0;
}

void Font::setImplementation(FontImplementation* implementation)
{
    if (_implementation.valid()) _implementation->_facade = 0;
    _implementation = implementation;
    if (_implementation.valid()) _implementation->_facade = this;
}

Font::FontImplementation* Font::getImplementation()
{
    return _implementation.get();
}

const Font::FontImplementation* Font::getImplementation() const
{
    return _implementation.get();
}

std::string Font::getFileName() const
{
    if (_implementation.valid()) return _implementation->getFileName();
    return "";
}

void Font::setSize(unsigned int width, unsigned int height)
{
    if (_implementation.valid()) _implementation->setSize(width, height);
}

unsigned int Font::getWidth()
{
    return _width;
}

unsigned int Font::getHeight()
{
    return _height;
}

void Font::setGlyphImageMargin(unsigned int margin)
{
    _margin = margin;
}

unsigned int Font::getGlyphImageMargin() const
{
    return _margin;
}

void Font::setTextureSizeHint(unsigned int width,unsigned int height)
{
    _textureWidthHint = width;
    _textureHeightHint = height;
}

unsigned int Font::getTextureWidthHint() const
{
    return _textureWidthHint;
}

unsigned int Font::getTextureHeightHint() const
{
    return _textureHeightHint;
}    


void Font::setMinFilterHint(osg::Texture::FilterMode mode)
{
    _minFilterHint = mode;
}

osg::Texture::FilterMode Font::getMinFilterHint() const
{
    return _minFilterHint;
}

/** Set the magnification texture filter to use when creating the texture to store the glyph images when rendering.
  * Note, this doesn't affect already created Texture Glhph's.*/
void Font::setMagFilterHint(osg::Texture::FilterMode mode)
{
    _magFilterHint = mode;
}

osg::Texture::FilterMode Font::getMagFilterHint() const
{
    return _magFilterHint;
}


Font::Glyph* Font::getGlyph(unsigned int charcode)
{
    SizeGlyphMap::iterator itr = _sizeGlyphMap.find(SizePair(_width,_height));
    if (itr!=_sizeGlyphMap.end())
    {
        GlyphMap& glyphmap = itr->second;    
        GlyphMap::iterator gitr = glyphmap.find(charcode);
        if (gitr!=glyphmap.end()) return gitr->second.get();
    }

    if (_implementation.valid()) return _implementation->getGlyph(charcode);
    else return 0;
}

osg::Vec2 Font::getKerning(unsigned int leftcharcode,unsigned int rightcharcode)
{
    if (_implementation.valid()) return _implementation->getKerning(leftcharcode,rightcharcode);
    else return osg::Vec2(0.0f,0.0f);
}

bool Font::hasVertical() const
{
    if (_implementation.valid()) return _implementation->hasVertical();
    else return false;
}



void Font::addGlyph(unsigned int width, unsigned int height, unsigned int charcode, Glyph* glyph)
{

    //cout << "charcode "<<(char)charcode<<"  "<<&_glyphTextureList<<endl;

    _sizeGlyphMap[SizePair(width,height)][charcode]=glyph;
    
    
    int posX=0,posY=0;
    
    GlyphTexture* glyphTexture = 0;
    for(GlyphTextureList::iterator itr=_glyphTextureList.begin();
        itr!=_glyphTextureList.end() && !glyphTexture;
        ++itr)
    {
        if ((*itr)->getSpaceForGlyph(glyph,posX,posY)) glyphTexture = itr->get();
    }
    
    if (glyphTexture)
    {
        //cout << "    found space for texture "<<glyphTexture<<" posX="<<posX<<" posY="<<posY<<endl;
    }
    
    if (!glyphTexture)
    {
        
        osg::StateSet* stateset = new osg::StateSet;
        _stateSetList.push_back(stateset);

        glyphTexture = new GlyphTexture;
        
        //std::cout<<"    Creating new GlyphTexture "<<glyphTexture<<"& StateSet "<<stateset<<std::endl;

        static int numberOfTexturesAllocated = 0;
        ++numberOfTexturesAllocated;
        //std::cout << "    " << this<< "  numberOfTexturesAllocated "<<numberOfTexturesAllocated<<std::endl;

        // reserve enough space for the glyphs.
        glyphTexture->setGlyphImageMargin(_margin);
        glyphTexture->setTextureSize(_textureWidthHint,_textureHeightHint);
        glyphTexture->setFilter(osg::Texture::MIN_FILTER,_minFilterHint);
        glyphTexture->setFilter(osg::Texture::MAG_FILTER,_magFilterHint);
        glyphTexture->setMaxAnisotropy(8);
        
        _glyphTextureList.push_back(glyphTexture);
        
        glyphTexture->setStateSet(stateset);
        stateset->setMode(GL_BLEND,osg::StateAttribute::ON);
        stateset->setTextureAttributeAndModes(0,glyphTexture,osg::StateAttribute::ON);
        stateset->setRenderingHint(osg::StateSet::TRANSPARENT_BIN);

        if (!glyphTexture->getSpaceForGlyph(glyph,posX,posY))
        {
            osg::notify(osg::WARN)<<"Warning: unable to allocate texture big enough for glyph"<<std::endl;
            return;
        }

    }    
    
    // add the glyph into the texture.
    glyphTexture->addGlyph(glyph,posX,posY);
    
}


Font::GlyphTexture::GlyphTexture():
    _stateset(0),
    _margin(2),
    _usedY(0),
    _partUsedX(0),
    _partUsedY(0)
{
}

Font::GlyphTexture::~GlyphTexture() 
{
}

// return -1 if *this < *rhs, 0 if *this==*rhs, 1 if *this>*rhs.
int Font::GlyphTexture::compare(const osg::StateAttribute& rhs) const
{
    if (this<&rhs) return -1;
    else if (this>&rhs) return 1;
    return 0;
}


bool Font::GlyphTexture::getSpaceForGlyph(Glyph* glyph, int& posX, int& posY)
{
        
    int width = glyph->s()+2*_margin;
    int height = glyph->t()+2*_margin;

    // first check box (_partUsedX,_usedY) to (width,height)
    if (width <= (getTextureWidth()-_partUsedX) &&
        height <= (getTextureHeight()-_usedY))
    {
        // can fit in existing row.

        // record the position in which the texture will be stored.
        posX = _partUsedX+_margin;
        posY = _usedY+_margin;        

        // move used markers on.
        _partUsedX += width;
        if (_usedY+height>_partUsedY) _partUsedY = _usedY+height;
        
        return true;
    }
    
    // start an new row.
    if (width <= getTextureWidth() &&
        height <= (getTextureHeight()-_partUsedY))
    {
        // can fit next row.
        _partUsedX = 0;
        _usedY = _partUsedY;

        posX = _partUsedX+_margin;
        posY = _usedY+_margin;        

        // move used markers on.
        _partUsedX += width;
        if (_usedY+height>_partUsedY) _partUsedY = _usedY+height;
        
        return true;
    }

    // doesn't fit into glyph.
    return false;
}

void Font::GlyphTexture::addGlyph(Glyph* glyph, int posX, int posY)
{

    _glyphs.push_back(glyph);
    for(unsigned int i=0;i<_glyphsToSubload.size();++i)
    {
        _glyphsToSubload[i].push_back(glyph);
    }

    // set up the details of where to place glyph's image in the texture.
    glyph->setTexture(this);
    glyph->setTexturePosition(posX,posY);
    glyph->setMinTexCoord(osg::Vec2((float)(posX+_margin-1)/(float)(getTextureWidth()-1),(float)(posY+_margin-1)/(float)(getTextureHeight()-1)));
    glyph->setMaxTexCoord(osg::Vec2((float)(posX+glyph->s()-_margin)/(float)(getTextureWidth()-1),(float)(posY+glyph->t()-_margin)/(float)(getTextureHeight()-1)));
}

void Font::GlyphTexture::apply(osg::State& state) const
{
    // get the contextID (user defined ID of 0 upwards) for the 
    // current OpenGL context.
    const unsigned int contextID = state.getContextID();

    if (contextID>=_glyphsToSubload.size())
    {
        // graphics context is beyond the number of glyphsToSubloads, so
        // we must now copy the glyph list across, this is a potential
        // threading issue though is multiple applies are happening the
        // same time on this object - to avoid this condition number of
        // graphics contexts should be set before create text.
        for(unsigned int i=_glyphsToSubload.size();i<=contextID;++i)
        {
            GlyphPtrList& glyphPtrs = _glyphsToSubload[i];
            for(GlyphRefList::const_iterator itr=_glyphs.begin();
                itr!=_glyphs.end();
                ++itr)
            {
                glyphPtrs.push_back(itr->get());
            }
        }
    }


    const Extensions* extensions = getExtensions(contextID,true);
    bool generateMipMapSupported = extensions->isGenerateMipMapSupported();

    // get the globj for the current contextID.
    GLuint& handle = getTextureObject(contextID);

    bool generateMipMapOn = false;

    if (handle == 0)
    {
        // being bound for the first time, need to allocate the texture
        glGenTextures( 1L, (GLuint *)&handle );
        glBindTexture( GL_TEXTURE_2D, handle );

        applyTexParameters(GL_TEXTURE_2D,state);

        
        // need to look at generate mip map extension if mip mapping required.
        switch(_min_filter)
        {
        case NEAREST_MIPMAP_NEAREST:
        case NEAREST_MIPMAP_LINEAR:
        case LINEAR_MIPMAP_NEAREST:
        case LINEAR_MIPMAP_LINEAR:
            if (generateMipMapSupported)
            {
                glTexParameteri(GL_TEXTURE_2D, GL_GENERATE_MIPMAP_SGIS,GL_TRUE);
                generateMipMapOn = true;
            }
            else glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, LINEAR);
            break;
        default:
            // not mip mapping so no problems.
            break;
        }
               
        // allocate the texture memory.
        glTexImage2D( GL_TEXTURE_2D, 0, GL_LUMINANCE_ALPHA,
                getTextureWidth(), getTextureHeight(), 0,
                GL_LUMINANCE_ALPHA,
                GL_UNSIGNED_BYTE,
                0 );
                
    
    }
    else
    {
        // reuse texture by binding.
        glBindTexture( GL_TEXTURE_2D, handle );
        if (getTextureParameterDirty(contextID))
        {
            applyTexParameters(GL_TEXTURE_2D,state);
        }
        bool generateMipMapOn = false;

        // need to look at generate mip map extension if mip mapping required.
        switch(_min_filter)
        {
        case NEAREST_MIPMAP_NEAREST:
        case NEAREST_MIPMAP_LINEAR:
        case LINEAR_MIPMAP_NEAREST:
        case LINEAR_MIPMAP_LINEAR:
            if (generateMipMapSupported)
            {
                glTexParameteri(GL_TEXTURE_2D, GL_GENERATE_MIPMAP_SGIS,GL_TRUE);
                generateMipMapOn = true;
            }
            else glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, LINEAR);
            break;
        default:
            // not mip mapping so no problems.
            break;
        }

    }
    

    // now subload the glyphs that are outstanding for this graphics context.
    GlyphPtrList& glyphsWereSubloading = _glyphsToSubload[contextID];

    if (!glyphsWereSubloading.empty())
    {

        for(GlyphPtrList::iterator itr=glyphsWereSubloading.begin();
            itr!=glyphsWereSubloading.end();
            ++itr)
        {
            (*itr)->subload();
        }
        
        // clear the list since we have now subloaded them.
        glyphsWereSubloading.clear();
    }
    else
    {
        //std::cout << "no need to subload "<<std::endl;
    }



    if (generateMipMapOn)
    {
        glTexParameteri(GL_TEXTURE_2D, GL_GENERATE_MIPMAP_SGIS,GL_FALSE);
    }


}

// all the methods in Font::Glyph have been made non inline because VisualStudio6.0 is STUPID, STUPID, STUPID PILE OF JUNK.
Font::Glyph::Glyph() {}
Font::Glyph::~Glyph() {}

unsigned int Font::Glyph::getGlyphCode() const { return _glyphCode; }

// void Font::Glyph::setFont(Font* font) { _font = font; }
// Font* Font::Glyph::getFont() const { return _font; }

void Font::Glyph::setHorizontalBearing(const osg::Vec2& bearing) {  _horizontalBearing=bearing; }
const osg::Vec2& Font::Glyph::getHorizontalBearing() const { return _horizontalBearing; }

void Font::Glyph::setHorizontalAdvance(float advance) { _horizontalAdvance=advance; }
float Font::Glyph::getHorizontalAdvance() const { return _horizontalAdvance; }

void Font::Glyph::setVerticalBearing(const osg::Vec2& bearing) {  _verticalBearing=bearing; }
const osg::Vec2& Font::Glyph::getVerticalBearing() const { return _verticalBearing; }

void Font::Glyph::setVerticalAdvance(float advance) {  _verticalAdvance=advance; }
float Font::Glyph::getVerticalAdvance() const { return _verticalAdvance; }

void Font::Glyph::setTexture(GlyphTexture* texture) { _texture = texture; }
Font::GlyphTexture* Font::Glyph::getTexture() { return _texture; }
const Font::GlyphTexture* Font::Glyph::getTexture() const { return _texture; }

osg::StateSet* Font::Glyph::getStateSet() { return _texture?_texture->getStateSet():0; }
const osg::StateSet* Font::Glyph::getStateSet() const { return _texture?_texture->getStateSet():0; }

void Font::Glyph::setTexturePosition(int posX,int posY) { _texturePosX = posX; _texturePosY = posY; }
int Font::Glyph::getTexturePositionX() const { return _texturePosX; }
int Font::Glyph::getTexturePositionY() const { return _texturePosY; }

void Font::Glyph::setMinTexCoord(const osg::Vec2& coord) { _minTexCoord=coord; }
const osg::Vec2& Font::Glyph::getMinTexCoord() const { return _minTexCoord; }

void Font::Glyph::setMaxTexCoord(const osg::Vec2& coord) { _maxTexCoord=coord; }
const osg::Vec2& Font::Glyph::getMaxTexCoord() const { return _maxTexCoord; }

void Font::Glyph::subload() const
{
    GLenum errorNo = glGetError();
    if (errorNo!=GL_NO_ERROR)
    {
        osg::notify(osg::WARN)<<"before Font::Glyph::subload(): detected OpenGL error '"<<gluErrorString(errorNo)<<std::endl;
    }

    glPixelStorei(GL_UNPACK_ALIGNMENT,getPacking());

    glTexSubImage2D(GL_TEXTURE_2D,0,
                    _texturePosX,_texturePosY,
                    s(),t(),
                    (GLenum)getPixelFormat(),
                    (GLenum)getDataType(),
                    data());
                    
    errorNo = glGetError();
    if (errorNo!=GL_NO_ERROR)
    {

        osg::notify(osg::WARN)<<"after Font::Glyph::subload() : detected OpenGL error '"<<gluErrorString(errorNo)<<"'"<<std::endl;
        std::cout << "\tglTexSubImage2D("<<GL_TEXTURE_2D<<" ,"<<0<<"\t"<<std::endl<<
                     "\t                "<<_texturePosX<<" ,"<<_texturePosY<<std::endl<<
                     "\t                "<<s()<<" ,"<<t()<<std::endl<<hex<<
                     "\t                0x"<<(GLenum)getPixelFormat()<<std::endl<<
                     "\t                0x"<<(GLenum)getDataType()<<std::endl<<
                     "\t                0x"<<(unsigned int)data()<<");"<<dec<<std::endl;
    }                    
}