/*
   render/textures.cc
   This file is part of the Osirion project and is distributed under
   the terms of the GNU General Public License version 2
*/

#include <string.h>

#include "render/render.h"
#include "render/gl.h"
#include "render/image.h"
#include "render/textures.h"
#include "render/state.h"

#include "sys/sys.h"
#include "core/application.h"

#include <GL/glu.h>

namespace render
{

std::map<std::string, size_t> Textures::registry;
GLuint Textures::textures[MAXTEXTURES];
GLuint Textures::textures_cubemap_id;
math::Vector2f Textures::texture_size[MAXTEXTURES];
std::string textures_cubemapname;

void Textures::init()
{
	con_print << "^BLoading textures..." << std::endl;

	glGenTextures(1, &textures_cubemap_id);
	
	if (registry.size()) {
		clear();
	} else {
		memset(textures, 0, sizeof(textures));
	}

	// "no texture" bitmap
	load("textures/common/notex");

	// gui font
	if (!load("bitmaps/fonts/gui", false)) {
		con_error << "Essential file bitmaps/fonts/gui missing" << std::endl;
		core::application()->shutdown();
	}

	// crosshairs
	load("bitmaps/pointers/pointer");
	load("bitmaps/pointers/aim");
	load("bitmaps/pointers/center");
	load("bitmaps/pointers/control");
	load("bitmaps/pointers/target");

	model::Material::set_imageloader_func(Textures::image_loader);
}

void Textures::shutdown()
{
	model::Material::set_imageloader_func(0);
	clear();
}

void Textures::list()
{
	for (iterator it = registry.begin(); it != registry.end(); it++) {
		con_print << "  " << (*it).first << " " << (*it).second << std::endl;
	}
	con_print << registry.size() << " loaded textures" << std::endl;
}

void Textures::clear()
{
	for (size_t i = 0; i < MAXTEXTURES; i++) {
		if (textures[i]) {
			glDeleteTextures(1, &textures[i]);
		}
		texture_size[i].clear();
	}

	registry.clear();
	memset(textures, 0, sizeof(textures));
	
	// clear cubemap
	glDeleteTextures(1, &textures_cubemap_id);
	textures_cubemap_id = 0;
	textures_cubemapname.clear();
}

void Textures::unload(const std::string &name)
{
	iterator it = registry.find(name);
	if (it != registry.end()) {
		con_debug << "  unloading " << (*it).first << std::endl;
		size_t id = (*it).second;
		// do not unload texture id 0, 'unkown texture'
		if (id && textures[id]) {
			glDeleteTextures(1, &textures[id]);
			textures[id] = 0;
			texture_size[id].clear();
		}
		registry.erase(it);
	}
}

void Textures::unload(const size_t id)
{
	// find in map
	for (iterator it = registry.begin(); it != registry.end(); it++) {
		if ((*it).second == id) {
			con_debug << "  unloading " << (*it).first << std::endl;
			size_t id = (*it).second;
			// do not unload texture id 0, 'unkown texture'
			if (id && textures[id]) {
				glDeleteTextures(1, &textures[id]);
				textures[id] = 0;
			}
			registry.erase(it);
			break;
		}
	}
}

void Textures::load_cubemap(const std::string & name)
{
	if (textures_cubemapname.compare(name) == 0) {
		// cubemap is already loaded
		return;
	}
	
	textures_cubemapname.assign(name);

	const GLenum cube_map[6] = {
		GL_TEXTURE_CUBE_MAP_POSITIVE_X,
		GL_TEXTURE_CUBE_MAP_NEGATIVE_X,
		GL_TEXTURE_CUBE_MAP_POSITIVE_Y,
		GL_TEXTURE_CUBE_MAP_NEGATIVE_Y,
		GL_TEXTURE_CUBE_MAP_POSITIVE_Z,
		GL_TEXTURE_CUBE_MAP_NEGATIVE_Z
		
	};
	
	Image *cube_texture[6] = {
		Image::load(name + "_front"),
		Image::load(name + "_back"),
		Image::load(name + "_left"),
		Image::load(name + "_right"),
		Image::load(name + "_up"),
		Image::load(name + "_down")

	};
	
	// load six skybox images and apply the necessary transformations
	
	if (cube_texture[0]) {
		Image *image = cube_texture[0];
		
		if (image->width() != image->height()) {
			con_warn << "  " << name << "_front: non-square sky texture!" << std::endl;
		} else {
			unsigned char pixel_data[image->channels()];
			
			for (size_t y = 0; y < image->height(); y++) {
				for (size_t x = y +1; x < image->width(); x++) {
					void *src = image->pixel(x, y);
					void *dst = image->pixel(y, x);
					memcpy(pixel_data, dst, image->channels());
					memcpy(dst, src, image->channels());
					memcpy(src, pixel_data, image->channels());
				}
				
			}
		}
	}
	
	if (cube_texture[1]) {
		Image *image = cube_texture[1];
		
		if (image->width() != image->height()) {
			con_warn << "  " << name << "_back: non-square sky texture!" << std::endl;
		} else {
			unsigned char pixel_data[image->channels()];
			
			for (size_t y = 0; y < image->height(); y++) {
				for (size_t x = y +1; x < image->width(); x++) {
					void *src = image->pixel(image->width() - x - 1, y);
					void *dst = image->pixel(image->height() - y - 1, x);
					memcpy(pixel_data, dst, image->channels());
					memcpy(dst, src, image->channels());
					memcpy(src, pixel_data, image->channels());
				}
				
			}
		}
	}
		
	if (cube_texture[2]) {
		cube_texture[2]->flip_vertical();
	}
	
	if (cube_texture[3]) {
		cube_texture[3]->flip_horizontal();
	}
	
	if (cube_texture[4]) {
		Image *image = cube_texture[4];
		
		if (image->width() != image->height()) {
			con_warn << "  " << name << "_back: non-square sky texture!" << std::endl;
		} else {
			unsigned char pixel_data[image->channels()];
			
			for (size_t y = 0; y < image->height(); y++) {
				for (size_t x = y +1; x < image->width(); x++) {
					void *src = image->pixel(x, y);
					void *dst = image->pixel(y, x);
					memcpy(pixel_data, dst, image->channels());
					memcpy(dst, src, image->channels());
					memcpy(src, pixel_data, image->channels());
				}
				
			}
		}
	}
	
	if (cube_texture[5]) {
		Image *image = cube_texture[5];
		
		if (image->width() != image->height()) {
			con_warn << "  " << name << "_down: non-square sky texture!" << std::endl;
		} else {
			unsigned char pixel_data[image->channels()];
			
			for (size_t y = 0; y < image->height(); y++) {
				for (size_t x = y +1; x < image->width(); x++) {
					void *src = image->pixel(x, y);
					void *dst = image->pixel(y, x);
					memcpy(pixel_data, dst, image->channels());
					memcpy(dst, src, image->channels());
					memcpy(src, pixel_data, image->channels());
				}
				
			}
		}
	}
		
	glBindTexture(GL_TEXTURE_CUBE_MAP, textures_cubemap_id);
	
	gl::texparameter(GL_TEXTURE_CUBE_MAP, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
	gl::texparameter(GL_TEXTURE_CUBE_MAP, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
	
	gl::texparameter(GL_TEXTURE_CUBE_MAP, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
	gl::texparameter(GL_TEXTURE_CUBE_MAP, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
	gl::texparameter(GL_TEXTURE_CUBE_MAP, GL_TEXTURE_WRAP_R, GL_CLAMP_TO_EDGE);
	
	gl::texparameter(GL_TEXTURE_CUBE_MAP, GL_TEXTURE_MAX_LEVEL, 0);
	
	for (size_t i = 0; i < 6; i++) {
		if (cube_texture[i]) {
			int texture_format;
			int texture_internalformat;
		
			if (cube_texture[i]->channels() == 4) {
				texture_format = GL_RGBA;
				texture_internalformat = GL_RGBA8;
			} else {
				texture_format = GL_RGB;
				texture_internalformat = GL_RGB8;
			}	
			glTexImage2D(cube_map[i], 0,
				texture_internalformat, cube_texture[i]->width(), cube_texture[i]->height(), 0,
				texture_format, GL_UNSIGNED_BYTE, cube_texture[i]->ptr());

			delete cube_texture[i];
		}
	}
}

size_t Textures::load(const char *name, const bool filter)
{
	if (name)
		return load(std::string(name), filter);
	else
		return 0;
}

size_t Textures::load(const std::string &name, const bool filter)
{
	// check if it is already loaded
	iterator it = registry.find(name);
	if (it != registry.end())
		return (*it).second;

	// find first available texture
	size_t id = 0;
	while ((id < MAXTEXTURES) && (textures[id])) {
		id++;
	}
	if (id == MAXTEXTURES) {
		con_error << "Texture limit " << MAXTEXTURES << " exceeded!" << std::endl;
		registry[name] = 0;
		return 0;
	}

	Image *image = Image::load(name);
	if (!image) {
		// add to the registry with id 0 (texture not found)
		registry[name] = 0;
		return 0;
	}

	glGenTextures(1, &textures[id]);
	glBindTexture(GL_TEXTURE_2D, textures[id]);

	int texture_format;
	int texture_internalformat;

	if (filter) {
		// scaling functions
		gl::texparameter(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_LINEAR);
		gl::texparameter(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
		// 4 levels of mipmaps
		gl::texparameter(GL_TEXTURE_2D, GL_TEXTURE_MAX_LEVEL, 4);

		if (r_mipmap->value()) {
			// hardware generated mipmaps (requires OpenGL 1.4)
			glTexParameteri(GL_TEXTURE_2D, GL_GENERATE_MIPMAP, GL_TRUE);
		}

		// enable texture wrapping
		gl::texparameter(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
		gl::texparameter(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
	} else {
		// scaling functions
		gl::texparameter(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
		gl::texparameter(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
		// no mipmaps, base level only
		gl::texparameter(GL_TEXTURE_2D, GL_TEXTURE_MAX_LEVEL, 0);
		
		gl::texparameter(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
		gl::texparameter(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
	}
	//gl::texenv(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE);

	if (image->channels() == 4) {
		texture_format = GL_RGBA;
		texture_internalformat = GL_RGBA8;
	} else {
		texture_format = GL_RGB;
		texture_internalformat = GL_RGB8;
	}

	if (filter && (r_mipmap->value() <= 0)) {
		gluBuild2DMipmaps(GL_TEXTURE_2D,
				  texture_internalformat, image->width(), image->height(),
				  texture_format, GL_UNSIGNED_BYTE, image->ptr());
	} else {
		glTexImage2D(GL_TEXTURE_2D, 0,
			     texture_internalformat, image->width(), image->height(), 0,
			     texture_format, GL_UNSIGNED_BYTE, image->ptr());
	}

	// add to the registry
	registry[name] = id;
	texture_size[id].assign((float) image->width(), (float) image->height());

	// delete image data
	delete image;

	return id;
}

size_t Textures::find(const std::string &name)
{
	size_t id = 0;
	iterator it = registry.find(name);
	if (it != registry.end())
		id = (*it).second;
	return id;
}

size_t Textures::bind(const char *name, const bool filter)
{
	if (name)
		return bind(std::string(name), filter);
	else
		return 0;
}

size_t Textures::bind(const std::string &name, const bool filter)
{
	size_t id = 0;
	iterator it = registry.find(name);
	if (it != registry.end()) {
		id = (*it).second;
		glBindTexture(GL_TEXTURE_2D, textures[id]);
	} else {
		id = load(name, filter);
	}

	return id;
}

size_t Textures::bind(const size_t texture, const bool filter)
{
	size_t id = texture;
	if (!textures[id])
		id = 0;

	glBindTexture(GL_TEXTURE_2D, textures[id]);
	return id;
}

void Textures::image_loader(model::Layer *layer)
{
	if (layer->texture().size() > 0 ) {
		size_t id = load(layer->texture().c_str());
		layer->set_texture_id(id);
		layer->set_size(texture_size[id]);
	}
}

}