/* -*-c++-*- Copyright (C) 2008 Miguel Escriva Gregori
 *
 * 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 <iostream>
#include <sstream>
#include <osg/Image>
#include <osg/Notify>

#include <osgDB/Registry>
#include <osgDB/FileNameUtils>
#include <osgDB/FileUtils>
#include <osgDB/ImageOptions>

extern "C" {
	#include <librsvg/rsvg.h>
	#include <librsvg/rsvg-cairo.h>
}

class ReaderWriterSVG : public osgDB::ReaderWriter
{
    public:
	ReaderWriterSVG()
	{
		rsvg_init();
	}

	virtual const char* className() const { return "SVG Image Reader"; }
	virtual bool acceptsExtension(const std::string& extension) const
	{
		return osgDB::equalCaseInsensitive(extension,"svg");
	}

	virtual ReadResult readObject(const std::string& file, const osgDB::ReaderWriter::Options* options) const
	{
		return readImage(file, options);
	}

	virtual ReadResult readImage(const std::string& file, const osgDB::ReaderWriter::Options* options) const
	{
		std::string ext = osgDB::getLowerCaseFileExtension(file);
		if (!acceptsExtension(ext)) return ReadResult::FILE_NOT_HANDLED;

		std::string fileName = osgDB::findDataFile( file, options );
		if (fileName.empty()) return ReadResult::FILE_NOT_FOUND;

		RsvgDimensionData dimensionData;
		RsvgHandle* handle = rsvg_handle_new_from_file (file.c_str(), NULL);
		rsvg_handle_get_dimensions( handle, &dimensionData);

		osg::Image *image;
		if (options)
		{
			unsigned int w=0, h=0;
			std::string op = options->getOptionString();			
			size_t i = op.find("x");

			std::stringstream ss1(op.substr(0, i));
			std::stringstream ss2(op.substr(i+1, op.size()));
			ss1 >> w;
			ss1 >> h;
			if (w==0 || h==0){
				image = createImage(handle, dimensionData.width, dimensionData.height);
			}
			else{
				image = createImage(handle, w, h);
			}
		}
		else{
			image = createImage(handle, dimensionData.width, dimensionData.height);
		}
		rsvg_handle_free(handle);
		image->setFileName(file);
		return image;
	}

	osg::Image* createImage(RsvgHandle *handle, unsigned int width, unsigned int height) const
	{
		RsvgDimensionData dimensionData;
		rsvg_handle_get_dimensions( handle, &dimensionData);
		// If image resollution < 128, cairo produces some artifacts.
		// I don't know why, but we check the size...
		if (width < 128) width = 128;
		if (height < 128) height = 128;
		width = osg::Image::computeNearestPowerOfTwo(width);
		height = osg::Image::computeNearestPowerOfTwo(height);
		osg::Image *image = new osg::Image();
		image->allocateImage(width, height, 1, GL_RGBA, GL_UNSIGNED_BYTE);
		image->setPixelFormat(GL_BGRA);

		cairo_surface_t *cairo_surface = cairo_image_surface_create_for_data(image->data(),
					CAIRO_FORMAT_ARGB32, width, height, image->getRowSizeInBytes());
		cairo_t *cr = cairo_create(cairo_surface);
		cairo_scale(cr,((float)width)/dimensionData.width, ((float)height)/dimensionData.height);
		rsvg_handle_render_cairo(handle, cr);
			
		cairo_destroy(cr);
		free(cairo_surface);

		image->flipVertical();
		return image;
	}
	protected:
		virtual ~ReaderWriterSVG()
		{
			rsvg_term();
		}
};

// now register with Registry to instantiate the above
// reader/writer.
REGISTER_OSGPLUGIN(SVG, ReaderWriterSVG)