/*******************************************************
      Lightwave Object Loader for OSG

  Copyright (C) 2004 Marco Jez <marco.jez@poste.it>
  OpenSceneGraph is (C) 2004 Robert Osfield
********************************************************/

#include "Converter.h"
#include "Tessellator.h"

#include <osg/Notify>
#include <osg/Geode>
#include <osg/Geometry>
#include <osg/CullFace>
#include <osg/LightModel>

#include <osgDB/FileUtils>

#include "lwo2parser.h"

#include <fstream>

using namespace lwosg;

namespace
{

	struct GeometryBin {
		osg::ref_ptr<osg::DrawElementsUInt> deui_points;
		osg::ref_ptr<osg::DrawElementsUInt> deui_lines;
		osg::ref_ptr<osg::DrawElementsUInt> deui_triangles;

		GeometryBin()
		:	deui_points(new osg::DrawElementsUInt(GL_POINTS)),
			deui_lines(new osg::DrawElementsUInt(GL_LINES)),
			deui_triangles(new osg::DrawElementsUInt(GL_TRIANGLES))
		{}
	};

}

Converter::Converter()
:	root_(new osg::Group)
{
}

Converter::Converter(const Options &options)
:	root_(new osg::Group),
	options_(options)
{
}

osg::Group *Converter::convert(Object &obj)
{
	if (root_->getNumChildren() > 0) {
		root_->removeChild(0, root_->getNumChildren());
	}

	osg::notify(osg::INFO) << "INFO: lwosg::Converter: flattening per-polygon vertex maps\n";
	for (Object::Layer_map::iterator i=obj.layers().begin(); i!=obj.layers().end(); ++i) {
		for (Layer::Unit_list::iterator j=i->second.units().begin(); j!=i->second.units().end(); ++j) {
			j->flatten_maps();
		}
	}

	osg::notify(osg::INFO) << "INFO: lwosg::Converter: creating scene graph\n";
	build_scene_graph(obj);

	return root_.get();
}

void Converter::build_scene_graph(Object &obj)
{
	// generate layer structure
	typedef std::map<int, osg::ref_ptr<osg::Group> > Layer_group_map;
	Layer_group_map lymap;

	osg::notify(osg::DEBUG_INFO) << "DEBUG INFO: lwosg::Converter: creating layer structure\n";

	// create a flat layer structure, no parenting since it's handled in scene files
	for (Object::Layer_map::const_iterator i=obj.layers().begin(); i!=obj.layers().end(); ++i) {
		const Layer &layer = i->second;
		osg::ref_ptr<osg::Group> new_group = new osg::Group;
		lymap[layer.number()] = new_group.get();
		if (layer.get_layer_chunk()) {
			new_group->setName(layer.get_layer_chunk()->name);
			if (layer.get_layer_chunk()->flags & 1) {
				new_group->setNodeMask(0);
			}
		} else {
			new_group->setName("Default_layer");
		}
		root_->addChild(new_group.get());
	}

	for (Object::Layer_map::iterator li=obj.layers().begin(); li!=obj.layers().end(); ++li) {
		Layer &layer = li->second;

		osg::Group *layer_group = lymap[layer.number()].get();

		osg::notify(osg::DEBUG_INFO) << "DEBUG INFO: lwosg::Converter: processing layer '" << layer_group->getName() << "'\n";

		for (Layer::Unit_list::iterator j=layer.units().begin(); j!=layer.units().end(); ++j) {

			osg::notify(osg::DEBUG_INFO) << "DEBUG INFO: lwosg::Converter: \tcreating primitives\n";

			int tess_success = 0;
			int tess_fail = 0;

			typedef std::map<const Surface *, GeometryBin> GeometryBin_map;
			GeometryBin_map bins;

			typedef std::map<const Surface *, Unit::Index_list> Remapping_map;
			Remapping_map remappings;

			// compute remapping map for default surface
			j->compute_vertex_remapping(0, remappings[0]);

			// compute remapping maps for other surfaces			
			for (Object::Surface_map::const_iterator h=obj.surfaces().begin(); h!=obj.surfaces().end(); ++h) {
				j->compute_vertex_remapping(&h->second, remappings[&h->second]);
			}

			// create primitive sets, taking into account remapping maps
			for (unsigned k=0; k<j->polygons().size(); ++k) {
				const Polygon &poly = j->polygons()[k];
				GeometryBin &bin = bins[poly.get_surface()];
				const Unit::Index_list &remapping = remappings[poly.get_surface()];

				if (poly.indices().size() == 1) {
					bin.deui_points->push_back(remapping[poly.indices()[0]]);
				}
				if (poly.indices().size() == 2) {
					bin.deui_lines->push_back(remapping[poly.indices()[0]]);
					bin.deui_lines->push_back(remapping[poly.indices()[1]]);
				}
				if (poly.indices().size() == 3) {
					bin.deui_triangles->push_back(remapping[poly.indices()[0]]);
					bin.deui_triangles->push_back(remapping[poly.indices()[1]]);
					bin.deui_triangles->push_back(remapping[poly.indices()[2]]);
				}
				if (poly.indices().size() >= 4) {
					Tessellator tess;
					if (tess.tessellate(poly, j->points(), bin.deui_triangles.get(), &remapping)) {
						++tess_success;
					} else {
						++tess_fail;
					}
				}
			}

			if (tess_success > 0) {
				osg::notify(osg::DEBUG_INFO) << "DEBUG INFO: lwosg::Converter:   " << tess_success << " polygons have been tessellated correctly\n";
			}

			if (tess_fail > 0) {
				osg::notify(osg::WARN) << "Warning: lwosg::Converter:   could not tessellate " << tess_fail << " polygons correctly. This is probably due to self-intersecting polygons being used, try to Triple them in Lightwave and restart the conversion" << std::endl;
			}

			// create normal array
			osg::ref_ptr<osg::Vec3Array> normals = j->normals()->asVec3Array(j->points()->size());

			for (GeometryBin_map::iterator i=bins.begin(); i!=bins.end(); ++i) {
				const Surface *surface = i->first;
				GeometryBin &bin = i->second;

				const Unit::Index_list &remapping = remappings[surface];

				// clean up points and normals according to remapping map
				osg::notify(osg::DEBUG_INFO) << "DEBUG INFO: lwosg::Converter: \tcleaning up redundant vertices and vertex attributes for surface '" << (surface ? surface->get_name() : std::string("anonymous")) << "'\n";				
				osg::ref_ptr<osg::Vec3Array> new_points = new osg::Vec3Array;
				osg::ref_ptr<osg::Vec3Array> new_normals = new osg::Vec3Array;
				for (unsigned pi=0; pi<j->points()->size(); ++pi) {
					if (remapping[pi] != -1) {
						new_points->push_back((*j->points())[pi]);
						new_normals->push_back((*normals)[pi]);
					}
				}
				
				osg::notify(osg::DEBUG_INFO) << "DEBUG INFO: lwosg::Converter: \tcreating geometry for surface '" << (surface ? surface->get_name() : std::string("anonymous")) << "'\n";

				osg::ref_ptr<osg::Geode> geode = new osg::Geode;

				osg::ref_ptr<osg::Geometry> geo = new osg::Geometry;
				geode->addDrawable(geo.get());

				geo->setVertexArray(new_points.get());
				geo->setNormalArray(new_normals.get());
				geo->setNormalBinding(osg::Geometry::BIND_PER_VERTEX);				

				if (surface) {
					geode->setName(surface->get_name());

					// apply surface parameters and texture/color maps according to remapping map
					osg::ref_ptr<VertexMap_map> rm_texture_maps = j->texture_maps()->remap(remapping);
					osg::ref_ptr<VertexMap_map> rm_rgb_maps = j->rgb_maps()->remap(remapping);
					osg::ref_ptr<VertexMap_map> rm_rgba_maps = j->rgba_maps()->remap(remapping);
					osg::Group *sgrp = surface->apply(geo.get(),
						rm_texture_maps.get(),
						rm_rgb_maps.get(),
						rm_rgba_maps.get(),
						options_.max_tex_units,
						options_.use_osgfx,
						options_.force_arb_compression);
					if (sgrp) {
						sgrp->addChild(geode.get());
						layer_group->addChild(sgrp);
					} else {
						layer_group->addChild(geode.get());
					}
				} else {
					layer_group->addChild(geode.get());
				}

				// add primitive sets to geometry
				if (!bin.deui_points->empty()) geo->addPrimitiveSet(bin.deui_points.get());
				if (!bin.deui_lines->empty()) geo->addPrimitiveSet(bin.deui_lines.get());
				if (!bin.deui_triangles->empty()) geo->addPrimitiveSet(bin.deui_triangles.get());
			}
		}

		osg::ref_ptr<osg::CullFace> cf = new osg::CullFace;
		cf->setMode(osg::CullFace::BACK);
		root_->getOrCreateStateSet()->setAttributeAndModes(cf.get());

		if (options_.apply_light_model) {
			osg::ref_ptr<osg::LightModel> lm = new osg::LightModel;
			lm->setTwoSided(true);
			lm->setColorControl(osg::LightModel::SEPARATE_SPECULAR_COLOR);
			lm->setAmbientIntensity(osg::Vec4(0, 0, 0, 0));
			lm->setLocalViewer(true);
			root_->getOrCreateStateSet()->setAttributeAndModes(lm.get());
		}
	}
}

osg::Group *Converter::convert(const iff::Chunk_list &data)
{
	Object obj(data);
	obj.set_coordinate_system_fixer(options_.csf.get());
	return convert(obj);
}

osg::Group *Converter::convert(const std::string &filename, const osgDB::ReaderWriter::Options* options)
{
	std::string file = osgDB::findDataFile(filename, options);
	if (file.empty()) return 0;

	std::ifstream ifs(file.c_str(), std::ios_base::in | std::ios_base::binary);
	if (!ifs.is_open()) return 0;

	std::vector<char> buffer;
	char c;
	while (ifs.get(c)) buffer.push_back(c);

	lwo2::Parser<std::vector<char>::const_iterator > parser(osg::notify(osg::DEBUG_INFO));

	try
	{
		parser.parse(buffer.begin(), buffer.end());
	}
	catch(lwo2::parser_error &e)
	{
		std::cerr << e.what() << std::endl;
		return 0;
	}

	for (iff::Chunk_list::const_iterator i=parser.chunks().begin(); i!=parser.chunks().end(); ++i) {
		const lwo2::FORM *form = dynamic_cast<const lwo2::FORM *>(*i);
		if (form) {
			Object obj(form->data);
			obj.set_coordinate_system_fixer(options_.csf.get());
			if (!convert(obj)) {
				return 0;
			}
			root_->setName(file);
			return root_.get();
		}
	}


	return 0;
}
