/*************************************************************************/
/*  texture_loader_dds.cpp                                               */
/*************************************************************************/
/*                       This file is part of:                           */
/*                           GODOT ENGINE                                */
/*                    http://www.godotengine.org                         */
/*************************************************************************/
/* Copyright (c) 2007-2017 Juan Linietsky, Ariel Manzur.                 */
/*                                                                       */
/* Permission is hereby granted, free of charge, to any person obtaining */
/* a copy of this software and associated documentation files (the       */
/* "Software"), to deal in the Software without restriction, including   */
/* without limitation the rights to use, copy, modify, merge, publish,   */
/* distribute, sublicense, and/or sell copies of the Software, and to    */
/* permit persons to whom the Software is furnished to do so, subject to */
/* the following conditions:                                             */
/*                                                                       */
/* The above copyright notice and this permission notice shall be        */
/* included in all copies or substantial portions of the Software.       */
/*                                                                       */
/* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,       */
/* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF    */
/* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.*/
/* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY  */
/* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,  */
/* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE     */
/* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.                */
/*************************************************************************/
#include "texture_loader_dds.h"
#include "os/file_access.h"


enum {
	DDS_MAGIC=0x20534444,
	DDSD_CAPS=0x00000001,
	DDSD_PIXELFORMAT=0x00001000,
	DDSD_PITCH=0x00000008,
	DDSD_LINEARSIZE=0x00080000,
	DDSD_MIPMAPCOUNT=0x00020000,
	DDPF_FOURCC=0x00000004,
	DDPF_ALPHAPIXELS=0x00000001,
	DDPF_INDEXED=0x00000020,
	DDPF_RGB=0x00000040,
};

enum DDSFormat {

	DDS_DXT1,
	DDS_DXT3,
	DDS_DXT5,
	DDS_ATI1,
	DDS_ATI2,
	DDS_BGRA8,
	DDS_BGR8,
	DDS_RGBA8, //flipped in dds
	DDS_RGB8, //flipped in dds
	DDS_BGR5A1,
	DDS_BGR565,
	DDS_BGR10A2,
	DDS_INDEXED,
	DDS_LUMINANCE,
	DDS_LUMINANCE_ALPHA,
	DDS_MAX
};

struct DDSFormatInfo {
	const char *name;
	bool compressed;
	bool palette;
	uint32_t divisor;
	uint32_t block_size;
	Image::Format format;
};


static const DDSFormatInfo dds_format_info[DDS_MAX]={
	{"DXT1",true,false,4,8,Image::FORMAT_BC1},
	{"DXT3",true,false,4,16,Image::FORMAT_BC2},
	{"DXT5",true,false,4,16,Image::FORMAT_BC3},
	{"ATI1",true,false,4,8,Image::FORMAT_BC4},
	{"ATI2",true,false,4,16,Image::FORMAT_BC5},
	{"BGRA8",false,false,1,4,Image::FORMAT_RGBA},
	{"BGR8",false,false,1,3,Image::FORMAT_RGB},
	{"RGBA8",false,false,1,4,Image::FORMAT_RGBA},
	{"RGB8",false,false,1,3,Image::FORMAT_RGB},
	{"BGR5A1",false,false,1,2,Image::FORMAT_RGBA},
	{"BGR565",false,false,1,2,Image::FORMAT_RGB},
	{"BGR10A2",false,false,1,4,Image::FORMAT_RGBA},
	{"INDEXED",false,true,1,1,Image::FORMAT_INDEXED},
	{"GRAYSCALE",false,false,1,1,Image::FORMAT_GRAYSCALE},
	{"GRAYSCALE_ALPHA",false,false,1,2,Image::FORMAT_GRAYSCALE_ALPHA}
};


RES ResourceFormatDDS::load(const String &p_path, const String& p_original_path, Error *r_error) {

	if (r_error)
		*r_error=ERR_CANT_OPEN;

	Error err;
	FileAccess *f = FileAccess::open(p_path,FileAccess::READ,&err);
	if (!f)
		return RES();

	FileAccessRef fref(f);
	if (r_error)
		*r_error=ERR_FILE_CORRUPT;

	ERR_EXPLAIN("Unable to open DDS texture file: "+p_path);
	ERR_FAIL_COND_V(err!=OK,RES());

	uint32_t magic = f->get_32();
	uint32_t hsize = f->get_32();
	uint32_t flags = f->get_32();
	uint32_t width = f->get_32();
	uint32_t height = f->get_32();
	uint32_t pitch = f->get_32();
	uint32_t depth = f->get_32();
	uint32_t mipmaps = f->get_32();

	//skip 11
	for(int i=0;i<11;i++)
		f->get_32();

	//validate

	if (magic!=DDS_MAGIC || hsize!=124 || !(flags&DDSD_PIXELFORMAT) || !(flags&DDSD_CAPS)) {

		ERR_EXPLAIN("Invalid or Unsupported DDS texture file: "+p_path);
		ERR_FAIL_V(RES());
	}


	uint32_t format_size = f->get_32();
	uint32_t format_flags = f->get_32();
	uint32_t format_fourcc = f->get_32();
	uint32_t format_rgb_bits = f->get_32();
	uint32_t format_red_mask = f->get_32();
	uint32_t format_green_mask = f->get_32();
	uint32_t format_blue_mask = f->get_32();
	uint32_t format_alpha_mask = f->get_32();

	uint32_t caps_1 = f->get_32();
	uint32_t caps_2 = f->get_32();
	uint32_t caps_ddsx = f->get_32();

	//reserved skip
	f->get_32();
	f->get_32();

	/*print_line("DDS width: "+itos(width));
	print_line("DDS height: "+itos(height));
	print_line("DDS mipmaps: "+itos(mipmaps));*/

	//printf("fourcc: %x fflags: %x, rgbbits: %x, fsize: %x\n",format_fourcc,format_flags,format_rgb_bits,format_size);
	//printf("rmask: %x gmask: %x, bmask: %x, amask: %x\n",format_red_mask,format_green_mask,format_blue_mask,format_alpha_mask);

	//must avoid this later
	while(f->get_pos()<128)
		f->get_8();


	DDSFormat dds_format;

	if (format_flags&DDPF_FOURCC && format_fourcc==0x31545844) { //'1TXD'

		dds_format=DDS_DXT1;
	} else if (format_flags&DDPF_FOURCC && format_fourcc==0x33545844) { //'3TXD'

		dds_format=DDS_DXT3;

	} else if (format_flags&DDPF_FOURCC && format_fourcc==0x35545844) { //'5TXD'

		dds_format=DDS_DXT5;
	} else if (format_flags&DDPF_FOURCC && format_fourcc==0x31495441) { //'1ITA'

		dds_format=DDS_ATI1;
	} else if (format_flags&DDPF_FOURCC && format_fourcc==0x32495441) { //'2ITA'

		dds_format=DDS_ATI2;

	} else if (format_flags&DDPF_RGB && format_flags&DDPF_ALPHAPIXELS && format_rgb_bits==32 && format_red_mask==0xff0000 && format_green_mask==0xff00 && format_blue_mask==0xff && format_alpha_mask==0xff000000) {

		dds_format=DDS_BGRA8;
	} else if (format_flags&DDPF_RGB && !(format_flags&DDPF_ALPHAPIXELS ) && format_rgb_bits==24 && format_red_mask==0xff0000 && format_green_mask==0xff00 && format_blue_mask==0xff) {

		dds_format=DDS_BGR8;
	} else if (format_flags&DDPF_RGB && format_flags&DDPF_ALPHAPIXELS && format_rgb_bits==32 && format_red_mask==0xff && format_green_mask==0xff00 && format_blue_mask==0xff0000 && format_alpha_mask==0xff000000) {

		dds_format=DDS_RGBA8;
	} else if (format_flags&DDPF_RGB && !(format_flags&DDPF_ALPHAPIXELS ) && format_rgb_bits==24 && format_red_mask==0xff && format_green_mask==0xff00 && format_blue_mask==0xff0000) {

		dds_format=DDS_RGB8;

	} else if (format_flags&DDPF_RGB && format_flags&DDPF_ALPHAPIXELS && format_rgb_bits==16 && format_red_mask==0x00007c00 && format_green_mask==0x000003e0 && format_blue_mask==0x0000001f && format_alpha_mask==0x00008000) {

		dds_format=DDS_BGR5A1;
	} else if (format_flags&DDPF_RGB && format_flags&DDPF_ALPHAPIXELS && format_rgb_bits==32 && format_red_mask==0x3ff00000 && format_green_mask==0xffc00 && format_blue_mask==0x3ff && format_alpha_mask==0xc0000000) {

		dds_format=DDS_BGR10A2;
	} else if (format_flags&DDPF_RGB && !(format_flags&DDPF_ALPHAPIXELS) && format_rgb_bits==16 && format_red_mask==0x0000f800 && format_green_mask==0x000007e0 && format_blue_mask==0x0000001f) {

		dds_format=DDS_BGR565;
	} else if (!(format_flags&DDPF_ALPHAPIXELS) && format_rgb_bits==8 && format_red_mask==0xff && format_green_mask==0xff && format_blue_mask==0xff) {

		dds_format=DDS_LUMINANCE;
	} else if ((format_flags&DDPF_ALPHAPIXELS) && format_rgb_bits==16 && format_red_mask==0xff && format_green_mask==0xff && format_blue_mask==0xff && format_alpha_mask==0xff00) {

		dds_format=DDS_LUMINANCE_ALPHA;
	} else if (format_flags&DDPF_INDEXED && format_rgb_bits==8) {

		dds_format=DDS_BGR565;
	} else {

		printf("unrecognized fourcc %x format_flags: %x - rgbbits %i - red_mask %x green mask %x blue mask %x alpha mask %x\n",format_fourcc,format_flags,format_rgb_bits,format_red_mask,format_green_mask,format_blue_mask,format_alpha_mask);
		ERR_EXPLAIN("Unrecognized or Unsupported color layout in DDS: "+p_path);

		ERR_FAIL_V(RES());

	}

	if (!(flags&DDSD_MIPMAPCOUNT))
		mipmaps=1;

//	print_line("found format: "+String(dds_format_info[dds_format].name));

	DVector<uint8_t> src_data;

	const DDSFormatInfo &info=dds_format_info[dds_format];
	uint32_t w = width;
	uint32_t h = height;


	if (info.compressed) {
		//compressed bc

		uint32_t size = MAX( info.divisor, w )/info.divisor * MAX( info.divisor, h )/info.divisor * info.block_size;
		ERR_FAIL_COND_V( size!=pitch, RES() );
		ERR_FAIL_COND_V( !(flags&DDSD_LINEARSIZE), RES() );

		for(uint32_t i=1;i<mipmaps;i++) {

			w=MAX(1,w>>1);
			h=MAX(1,h>>1);
			uint32_t bsize = MAX( info.divisor, w )/info.divisor * MAX( info.divisor, h )/info.divisor * info.block_size;
			//printf("%i x %i - block: %i\n",w,h,bsize);
			size+= bsize;
		}

		src_data.resize(size);
		DVector<uint8_t>::Write wb = src_data.write();
		f->get_buffer(wb.ptr(),size);
		wb=DVector<uint8_t>::Write();

	} else if (info.palette) {

		//indexed
		ERR_FAIL_COND_V( !(flags&DDSD_PITCH), RES());
		ERR_FAIL_COND_V( format_rgb_bits!=8, RES() );

		uint32_t size = pitch*height;
		ERR_FAIL_COND_V( size != width*height * info.block_size, RES());

		uint8_t pallete[256*4];
		f->get_buffer(pallete,256*4);

		int colsize=3;
		for(int i=0;i<256;i++) {

			if (pallete[i*4+3]<255)
				colsize=4;
		}

		int w = width;
		int h = height;

		for(uint32_t i=1;i<mipmaps;i++) {

			w=(w+1)>>1;
			h=(h+1)>>1;
			size+= w*h*info.block_size;
		}

		src_data.resize(size + 256*colsize );
		DVector<uint8_t>::Write wb = src_data.write();
		f->get_buffer(wb.ptr(),size);

		for(int i=0;i<256;i++) {

			int dst_ofs = size+i*colsize;
			int src_ofs = i*4;
			wb[dst_ofs+0]=pallete[src_ofs+2];
			wb[dst_ofs+1]=pallete[src_ofs+1];
			wb[dst_ofs+2]=pallete[src_ofs+0];
			if (colsize==4)
				wb[dst_ofs+3]=pallete[src_ofs+3];
		}


		wb=DVector<uint8_t>::Write();
	} else {
		//uncompressed generic...

		uint32_t size = width*height*info.block_size;


		for(uint32_t i=1;i<mipmaps;i++) {

			w=(w+1)>>1;
			h=(h+1)>>1;
			size+= w*h*info.block_size;
		}

		if (dds_format==DDS_BGR565)
			size=size*3/2;
		else if (dds_format==DDS_BGR5A1)
			size=size*2;

		src_data.resize(size);
		DVector<uint8_t>::Write wb = src_data.write();
		f->get_buffer(wb.ptr(),size);


		switch(dds_format) {

			case DDS_BGR5A1: {

				// TO RGBA
				int colcount = size/4;

				for(int i=colcount-1;i>=0;i--) {

					int src_ofs = i*2;
					int dst_ofs = i*4;

					uint8_t a=wb[src_ofs+1]&0x80;
					uint8_t b= wb[src_ofs]&0x1F;
					uint8_t g= (wb[src_ofs]>>5) | ((wb[src_ofs+1]&0x3)<<3);
					uint8_t r= (wb[src_ofs+1]>>2)&0x1F;
					wb[dst_ofs+0]=r<<3;
					wb[dst_ofs+1]=g<<3;
					wb[dst_ofs+2]=b<<3;
					wb[dst_ofs+3]=a?255:0;
				}
			} break;
			case DDS_BGR565: {

				int colcount = size/3;

				for(int i=colcount-1;i>=0;i--) {

					int src_ofs = i*2;
					int dst_ofs = i*3;

					uint8_t b= wb[src_ofs]&0x1F;
					uint8_t g= (wb[src_ofs]>>5) | ((wb[src_ofs+1]&0x7)<<3);
					uint8_t r= wb[src_ofs+1]>>3;
					wb[dst_ofs+0]=r<<3;
					wb[dst_ofs+1]=g<<2;
					wb[dst_ofs+2]=b<<3;//b<<3;

				}

			} break;
			case DDS_BGR10A2: {

				// TO RGBA
				int colcount = size/4;

				for(int i=colcount-1;i>=0;i--) {

					int ofs = i*4;

					uint32_t w32 = uint32_t(wb[ofs+0]) | (uint32_t(wb[ofs+1])<<8) | (uint32_t(wb[ofs+2])<<16) | (uint32_t(wb[ofs+3])<<24);

					uint8_t a= (w32&0xc0000000) >> 24;
					uint8_t r= (w32&0x3ff00000) >> 22;
					uint8_t g= (w32&0xffc00) >> 12;
					uint8_t b= (w32&0x3ff) >> 2;


					wb[ofs+0]=r;
					wb[ofs+1]=g;
					wb[ofs+2]=b;
					wb[ofs+3]=a==0xc0 ? 255 : a; //0xc0 should be opaque

				}
			} break;
			case DDS_BGRA8: {

				int colcount = size/4;

				for(int i=0;i<colcount;i++) {

					SWAP( wb[i*4+0],wb[i*4+2] );
				}

			} break;
			case DDS_BGR8: {

				int colcount = size/3;

				for(int i=0;i<colcount;i++) {

					SWAP( wb[i*3+0],wb[i*3+2] );
				}
			} break;
			case DDS_RGBA8: {

					/* do nothing either
				int colcount = size/4;

				for(int i=0;i<colcount;i++) {

					uint8_t r = wb[i*4+1];
					uint8_t g = wb[i*4+2];
					uint8_t b = wb[i*4+3];
					uint8_t a = wb[i*4+0];

					wb[i*4+0]=r;
					wb[i*4+1]=g;
					wb[i*4+2]=b;
					wb[i*4+3]=a;
				}
				*/
			} break;
			case DDS_RGB8: {

				// do nothing
				/*
				int colcount = size/3;

				for(int i=0;i<colcount;i++) {

					SWAP( wb[i*3+0],wb[i*3+2] );
				}*/
			} break;
			case DDS_LUMINANCE: {

				// do nothing i guess?

			} break;
			case DDS_LUMINANCE_ALPHA: {

				// do nothing i guess?

			} break;

			default: {}

		}

		wb=DVector<uint8_t>::Write();
	}


	Image img(width,height,mipmaps-1,info.format,src_data);

	Ref<ImageTexture> texture = memnew( ImageTexture );
	texture->create_from_image(img);

	if (r_error)
		*r_error=OK;


	return texture;

}

void ResourceFormatDDS::get_recognized_extensions(List<String> *p_extensions) const {

	p_extensions->push_back("dds");
}

bool ResourceFormatDDS::handles_type(const String& p_type) const {

	return ObjectTypeDB::is_type(p_type,"Texture");
}

String ResourceFormatDDS::get_resource_type(const String &p_path) const {

	if (p_path.extension().to_lower()=="dds")
		return "ImageTexture";
	return "";
}