// ==============================================================
//	This file is part of Glest Shared Library (www.glest.org)
//
//	Copyright (C) 2001-2010 Martiño Figueroa and others
//
//	You can redistribute this code and/or modify it under
//	the terms of the GNU General Public License as published
//	by the Free Software Foundation; either version 2 of the
//	License, or (at your option) any later version
// ==============================================================

#include "JPGReader.h"
#include "FileReader.h"

#include "types.h"
#include "pixmap.h"
#include <stdexcept>
#include <jpeglib.h>
#include <setjmp.h>

#include "util.h"
#include "leak_dumper.h"

using std::runtime_error;
using std::ios;

/**Used things from CImageLoaderJPG.cpp from Irrlicht*/

namespace Shared{ namespace Graphics{

// =====================================================
//	Methods used for JPG-Decompression
// =====================================================


//Methods used by jpeglib
static void init_source(j_decompress_ptr cinfo) {
	//It already is initialized
}
static boolean fill_input_buffer (j_decompress_ptr cinfo) {
	//it is already filled
	return true;
}
static void skip_input_data (j_decompress_ptr cinfo, long num_bytes) {
	if (num_bytes > 0) {
		jpeg_source_mgr* This = cinfo->src;
		This->bytes_in_buffer-= num_bytes;
		This->next_input_byte+= num_bytes;
	}
}
static void term_source (j_decompress_ptr cinfo) {
}

// =====================================================
//	class JPGReader
// =====================================================

/**Return an array containing the used extensions,
  * initialized*/
//static inline const string* getExtensions() {
	//static const string extensions[] = {"jpg", "jpeg", ""};
static inline std::vector<string> getExtensions() {
	static std::vector<string> extensions;
	if(extensions.empty() == true) {
		extensions.push_back("jpg");
		extensions.push_back("jpeg");
	}

	return extensions;
}

JPGReader::JPGReader(): FileReader<Pixmap2D>(getExtensions()) {}

Pixmap2D* JPGReader::read(ifstream& is, const string& path, Pixmap2D* ret) const {
	assert(GlobalStaticFlags::getIsNonGraphicalModeEnabled() == false);
	//Read file
	is.seekg(0, ios::end);
	size_t length = is.tellg();
	if (length < 8) {
		return NULL;
	}
	is.seekg(0, ios::beg);
	uint8 *buffer = new uint8[length];
	is.read((char*)buffer, (std::streamsize)length);
	//Check buffer (weak jpeg check)
	//if (buffer[0] != 0x46 || buffer[1] != 0xA0) {
	// Proper header check found from: http://www.fastgraph.com/help/jpeg_header_format.html
	if (buffer[0] != 0xFF || buffer[1] != 0xD8) {
	    std::cout << "0 = [" << std::hex << (int)buffer[0] << "] 1 = [" << std::hex << (int)buffer[1] << "]" << std::endl;
		delete[] buffer;
		return NULL;
	}

	struct jpeg_decompress_struct cinfo;
	struct jpeg_error_mgr jerr;

	JSAMPROW row_pointer[1];
	row_pointer[0] = NULL;
	cinfo.err = jpeg_std_error( &jerr ); //Standard error handler
	jpeg_create_decompress( &cinfo ); //Create decompressing structure
	struct jpeg_source_mgr source;

	jmp_buf error_buffer; //Used for saving/restoring context
	// Set up data pointer
	source.bytes_in_buffer = length;
	source.next_input_byte = (JOCTET*)buffer;
	cinfo.src = &source;

	if (setjmp(error_buffer)) { //Longjump was called --> an exception was thrown
		delete[] buffer;
		jpeg_destroy_decompress(&cinfo);
		if (row_pointer[0] != NULL) {
			delete[] row_pointer[0];
		}
		return NULL;
	}

	source.init_source = init_source;
	source.fill_input_buffer = fill_input_buffer;
	source.resync_to_restart = jpeg_resync_to_restart;
	source.skip_input_data = skip_input_data;
	source.term_source = term_source;

	/* reading the image header which contains image information */
	if (jpeg_read_header( &cinfo, TRUE ) != JPEG_HEADER_OK) {
		delete[] buffer;
		jpeg_destroy_decompress(&cinfo);
		return NULL;
	}


	/*std::cout << "JPEG FILE Information: " << std::endl;
	std::cout << "Image width and height: " << cinfo.image_width <<" pixels and " << cinfo.image_height <<" pixels." << std::endl;

	std::cout << "Color components per fixel: " << cinfo.num_components << std::endl;
	std::cout << "Color space: " << cinfo.jpeg_color_space << std::endl;*/
	int picComponents = (ret->getComponents() == -1)?cinfo.num_components:ret->getComponents();
	//std::cout << "JPG-Components: Pic: " << picComponents << " old: " << (ret->getComponents()) << " File: " << cinfo.num_components << std::endl;
	//picComponents = 4;
	//TODO: Irrlicht has some special CMYK-handling - maybe needed too?
	/* Start decompression jpeg here */
	jpeg_start_decompress( &cinfo );
	ret->init(cinfo.image_width, cinfo.image_height, picComponents);
	uint8* pixels = ret->getPixels();
	//std::cout << "output width and height: " << cinfo.output_width <<" pixels and " << cinfo.output_height <<" pixels." << std::endl;
	/* now actually read the jpeg into the raw buffer */
	row_pointer[0] = new unsigned char[cinfo.output_width*cinfo.num_components];
	size_t location = 0; //Current pixel
	/* read one scan line at a time */
	/* Again you need to invert the lines unfortunately*/
	while( cinfo.output_scanline < cinfo.output_height )
	{
		jpeg_read_scanlines( &cinfo, row_pointer, 1 );
		location = (cinfo.output_height - cinfo.output_scanline)*cinfo.output_width*picComponents;
		if (picComponents == cinfo.num_components) {
			memcpy(pixels+location,row_pointer[0],cinfo.output_width*cinfo.num_components);
		} else {
			int r,g,b,a,l;
			for (unsigned int xPic = 0, xFile = 0; xPic < cinfo.output_width*picComponents; xPic+= picComponents, xFile+= cinfo.num_components) {
				switch(cinfo.num_components) {
					case 3:
						r = row_pointer[0][xFile];
						g = row_pointer[0][xFile+1];
						b = row_pointer[0][xFile+2];
						l = (r+g+b+2)/3;
						a = 255;
						break;
					case 4:
						r = row_pointer[0][xFile];
						g = row_pointer[0][xFile+1];
						b = row_pointer[0][xFile+2];
						l = (r+g+b+2)/3;
						a = row_pointer[0][xFile+3];
						break;
					default:
						//TODO: Error
					case 1:
						r = g = b = l = row_pointer[0][xFile];
						a = 255;
						break;
				}
				switch (picComponents) {
					case 1:
						pixels[location+xPic] = l;
						break;
					case 4:
						pixels[location+xPic+3] = a; //Next case
					case 3:
						pixels[location+xPic] = r;
						pixels[location+xPic+1] = g;
						pixels[location+xPic+2] = b;
						break;
					default:
						//just so at least something works
						for (int i = 0; i < picComponents; ++i) {
							pixels[location+xPic+i] = l;
						}
						//TODO: Error
				}
			}
		}
	}
	/*for(int i = 0; i < cinfo.image_width*cinfo.image_height*picComponents; ++i) {
		if (i%39 == 0) std::cout << std::endl;
		int first = pixels[i]/16;
		if (first < 10)
			std:: cout << first;
		else
			std::cout << (char)('A'+(first-10));
		first = pixels[i]%16;
		if (first < 10)
			std:: cout << first;
		else
			std::cout << (char)('A'+(first-10));
		std::cout << " ";		
	}*/
	/* wrap up decompression, destroy objects, free pointers and close open files */
	jpeg_finish_decompress( &cinfo );
	jpeg_destroy_decompress( &cinfo );
	delete[] row_pointer[0];

	delete[] buffer;

	return ret;
}

}} //end namespace