// ==============================================================
//	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 "PNGReader.h"

#include "data_types.h"
#include "pixmap.h"
#include <stdexcept>
#include <png.h>
#include <setjmp.h>
#include "util.h"
#include "leak_dumper.h"

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

namespace Shared {
	namespace Graphics {

		// =====================================================
		//	Callbacks for PNG-decompression
		// =====================================================

		static void user_read_data(png_structp read_ptr, png_bytep data, png_size_t length) {
			ifstream& is = *((ifstream*) png_get_io_ptr(read_ptr));
			is.read((char*) data, (std::streamsize)length);
			static bool bigEndianSystem = Shared::PlatformByteOrder::isBigEndian();
			if (bigEndianSystem == true) {
				Shared::PlatformByteOrder::fromEndianTypeArray<png_byte>(data, length);
			}

			if (!is.good()) {
				png_error(read_ptr, "Could not read from png-file");
			}
		}

		//static void user_write_data(png_structp png_ptr, png_bytep data, png_size_t length) {}

		//static void user_flush_data(png_structp png_ptr) {}

		/**Get Extension array, initialised*/
		//static inline const string* getExtensionsPng() {
		static inline std::vector<string> getExtensionsPng() {
			//static const string extensions[] = {"png", ""};
			static std::vector<string> extensions;
			if (extensions.empty() == true) {
				extensions.push_back("png");
			}
			return extensions;
		}

		// =====================================================
		//	class PNGReader
		// =====================================================

		PNGReader::PNGReader() : FileReader<Pixmap2D>(getExtensionsPng()) {
		}

		Pixmap2D* PNGReader::read(ifstream& is, const string& path, Pixmap2D* ret) const {
			if (GlobalStaticFlags::getIsNonGraphicalModeEnabled() == true) {
				throw megaglest_runtime_error("Loading graphics in headless server mode not allowed!");
			}

			//Read file
			is.seekg(0, ios::end);
			//size_t length = is.tellg();
			is.seekg(0, ios::beg);
			uint8 *buffer = new uint8[8];
			is.read((char*) buffer, 8);
			static bool bigEndianSystem = Shared::PlatformByteOrder::isBigEndian();
			if (bigEndianSystem == true) {
				Shared::PlatformByteOrder::fromEndianTypeArray<uint8>(buffer, 8);
			}

			if (png_sig_cmp(buffer, 0, 8) != 0) {
				delete[] buffer;
				//This is not a PNG file - could be used for fast checking whether file is supported or not
				throw megaglest_runtime_error(path + " is not a png", true);
			}

			png_structp png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING, NULL, NULL, NULL);
			if (!png_ptr) {
				delete[] buffer;
				throw megaglest_runtime_error(path + " is a corrupt(1) png", true);
			}
			png_infop info_ptr = png_create_info_struct(png_ptr);
			if (!info_ptr) {
				png_destroy_read_struct(&png_ptr, (png_infopp) NULL, (png_infopp) NULL);
				delete[] buffer;
				throw megaglest_runtime_error(path + " is a corrupt(2) png", true);
			}
			if (setjmp(png_jmpbuf(png_ptr))) {
				png_destroy_read_struct(&png_ptr, &info_ptr, (png_infopp) NULL);
				delete[] buffer;
				//Error during init_io
				throw megaglest_runtime_error(path + " is a corrupt(3) png", true);
			}
			png_set_read_fn(png_ptr, &is, user_read_data);
			png_set_sig_bytes(png_ptr, 8);
			png_read_info(png_ptr, info_ptr);

			int width = png_get_image_width(png_ptr, info_ptr);

			int height = png_get_image_height(png_ptr, info_ptr);
			int color_type = png_get_color_type(png_ptr, info_ptr);
			//int bit_depth = info_ptr->bit_depth;

			//We want RGB, 24 bit
			if (color_type == PNG_COLOR_TYPE_PALETTE ||
				(color_type == PNG_COLOR_TYPE_GRAY && png_get_bit_depth(png_ptr, info_ptr) < 8) ||
				(png_get_valid(png_ptr, info_ptr, PNG_INFO_tRNS))) {
				png_set_expand(png_ptr);
			}

			if (color_type == PNG_COLOR_TYPE_GRAY) {
				png_set_gray_to_rgb(png_ptr);
			}

			//int number_of_passes = png_set_interlace_handling(png_ptr);
			png_set_interlace_handling(png_ptr);
			png_read_update_info(png_ptr, info_ptr);
			png_bytep* row_pointers = new png_bytep[height];

			if (setjmp(png_jmpbuf(png_ptr))) {
				delete[] row_pointers;
				delete[] buffer;
				//error during read_image
				throw megaglest_runtime_error(path + " is a corrupt(4) png", true);
			}
			for (int y = 0; y < height; ++y) {
				row_pointers[y] = new png_byte[png_get_rowbytes(png_ptr, info_ptr)];
			}
			png_read_image(png_ptr, row_pointers);
			size_t fileComponents = png_get_rowbytes(png_ptr, info_ptr) / width;
			size_t picComponents = (ret->getComponents() == -1) ? fileComponents : ret->getComponents();
			//std::cout << "PNG-Components: Pic: " << picComponents << " old: " << (ret->getComponents()) << " File: " << fileComponents << std::endl;
			//picComponents = 4;
			//Copy image
			ret->init(width, height, (int) picComponents);
			uint8* pixels = ret->getPixels();
			const size_t rowbytes = png_get_rowbytes(png_ptr, info_ptr);
			size_t location = 0;
			for (int y = height - 1; y >= 0; --y) { //you have to somehow invert the lines
				if (picComponents == fileComponents) {
					memcpy(pixels + location, row_pointers[y], rowbytes);
				} else {
					int r, g, b, a, l;
					for (size_t xPic = 0, xFile = 0; xFile < rowbytes; xPic += picComponents, xFile += fileComponents) {
						switch (fileComponents) {
							case 3:
								r = row_pointers[y][xFile];
								g = row_pointers[y][xFile + 1];
								b = row_pointers[y][xFile + 2];
								l = (r + g + b + 2) / 3;
								a = 255;
								break;
							case 4:
								r = row_pointers[y][xFile];
								g = row_pointers[y][xFile + 1];
								b = row_pointers[y][xFile + 2];
								l = (r + g + b + 2) / 3;
								a = row_pointers[y][xFile + 3];
								break;
							default:
								// Possible Error
							case 1:
								r = g = b = l = row_pointers[y][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 (unsigned int i = 0; i < picComponents; ++i) {
									pixels[location + xPic + i] = l;
								}
								break;
								// Possible Error
						}
					}
				}
				location += picComponents * width;
			}

			for (int y = 0; y < height; ++y) {
				delete[] row_pointers[y];
			}
			delete[] row_pointers;

			png_destroy_read_struct(&png_ptr, &info_ptr, (png_infopp) NULL);

			delete[] buffer;

			return ret;
		}



		PNGReader3D::PNGReader3D() : FileReader<Pixmap3D>(getExtensionsPng()) {
		}

		Pixmap3D* PNGReader3D::read(ifstream& is, const string& path, Pixmap3D* ret) const {
			//Read file
			is.seekg(0, ios::end);
			//size_t length = is.tellg();
			is.seekg(0, ios::beg);
			uint8 *buffer = new uint8[8];
			is.read((char*) buffer, 8);
			static bool bigEndianSystem = Shared::PlatformByteOrder::isBigEndian();
			if (bigEndianSystem == true) {
				Shared::PlatformByteOrder::fromEndianTypeArray<uint8>(buffer, 8);
			}

			if (png_sig_cmp(buffer, 0, 8) != 0) {
				delete[] buffer;
				//This is not a PNG file - could be used for fast checking whether file is supported or not
				throw megaglest_runtime_error(path + " is not a png(2)", true);
			}

			png_structp png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING, NULL, NULL, NULL);
			if (!png_ptr) {
				delete[] buffer;
				throw megaglest_runtime_error(path + " is a corrupt(5) png", true);
			}
			png_infop info_ptr = png_create_info_struct(png_ptr);
			if (!info_ptr) {
				png_destroy_read_struct(&png_ptr, (png_infopp) NULL, (png_infopp) NULL);
				delete[] buffer;
				throw megaglest_runtime_error(path + " is a corrupt(6) png", true);
			}
			if (setjmp(png_jmpbuf(png_ptr))) {
				png_destroy_read_struct(&png_ptr, &info_ptr, (png_infopp) NULL);
				delete[] buffer;
				//Error during init_io
				throw megaglest_runtime_error(path + " is a corrupt(7) png", true);
			}
			png_set_read_fn(png_ptr, &is, user_read_data);
			png_set_sig_bytes(png_ptr, 8);
			png_read_info(png_ptr, info_ptr);

			int width = png_get_image_width(png_ptr, info_ptr);
			int height = png_get_image_height(png_ptr, info_ptr);
			int color_type = png_get_color_type(png_ptr, info_ptr);
			//int bit_depth = info_ptr->bit_depth;

			//We want RGB, 24 bit
			if (color_type == PNG_COLOR_TYPE_PALETTE ||
				(color_type == PNG_COLOR_TYPE_GRAY && png_get_bit_depth(png_ptr, info_ptr) < 8) ||
				(png_get_valid(png_ptr, info_ptr, PNG_INFO_tRNS))) {
				png_set_expand(png_ptr);
			}

			if (color_type == PNG_COLOR_TYPE_GRAY) {
				png_set_gray_to_rgb(png_ptr);
			}

			//int number_of_passes = png_set_interlace_handling(png_ptr);
			png_set_interlace_handling(png_ptr);
			png_read_update_info(png_ptr, info_ptr);
			png_bytep* row_pointers = new png_bytep[height];

			if (setjmp(png_jmpbuf(png_ptr))) {
				delete[] row_pointers;
				delete[] buffer;
				//error during read_image
				throw megaglest_runtime_error(path + " is a corrupt(8) png", true);
			}
			for (int y = 0; y < height; ++y) {
				row_pointers[y] = new png_byte[png_get_rowbytes(png_ptr, info_ptr)];
			}
			png_read_image(png_ptr, row_pointers);
			size_t fileComponents = png_get_rowbytes(png_ptr, info_ptr) / width;
			size_t picComponents = (ret->getComponents() == -1) ? fileComponents : ret->getComponents();
			const int d = ret->getD();
			const int slice = ret->getSlice();
			if (ret->getPixels() == NULL) {
				ret->init(width, height, d, (int) picComponents);
			}

			//std::cout << "PNG-Components: Pic: " << picComponents << " old: " << (ret->getComponents()) << " File: " << fileComponents << std::endl;
			//picComponents = 4;
			//Copy image
			//printf("pixmap3d loading path [%s] w = %d h = %d d = %d comp = %d\n",path.c_str(),width,height,ret->getD(),picComponents);
			uint8* pixels = ret->getPixels();
			if (slice > 0) {
				pixels = &pixels[slice*width*height*picComponents];
			}

			const size_t rowbytes = png_get_rowbytes(png_ptr, info_ptr);
			size_t location = 0;
			for (int y = height - 1; y >= 0; --y) { //you have to somehow invert the lines
				if (picComponents == fileComponents) {
					memcpy(pixels + location, row_pointers[y], rowbytes);
				} else {
					int r, g, b, a, l;
					for (size_t xPic = 0, xFile = 0; xFile < rowbytes; xPic += picComponents, xFile += fileComponents) {
						switch (fileComponents) {
							case 3:
								r = row_pointers[y][xFile];
								g = row_pointers[y][xFile + 1];
								b = row_pointers[y][xFile + 2];
								l = (r + g + b + 2) / 3;
								a = 255;
								break;
							case 4:
								r = row_pointers[y][xFile];
								g = row_pointers[y][xFile + 1];
								b = row_pointers[y][xFile + 2];
								l = (r + g + b + 2) / 3;
								a = row_pointers[y][xFile + 3];
								break;
							default:
								// Possible Error
							case 1:
								r = g = b = l = row_pointers[y][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 (unsigned int i = 0; i < picComponents; ++i) {
									pixels[location + xPic + i] = l;
								}
								break;
								// Possible Error
						}
					}
				}
				location += picComponents * width;
			}

			for (int y = 0; y < height; ++y) {
				delete[] row_pointers[y];
			}
			delete[] row_pointers;

			png_destroy_read_struct(&png_ptr, &info_ptr, (png_infopp) NULL);

			delete[] buffer;

			return ret;
		}


	}
} //end namespace