/* === S Y N F I G ========================================================= */
/*!	\file trgt_gif.cpp
**	\brief GIF Target Module
**
**	\legal
**	Copyright (c) 2002-2005 Robert B. Quattlebaum Jr., Adrian Bentley
**	Copyright (c) 2007 Chris Moore
**
**	This file is part of Synfig.
**
**	Synfig is free software: you can redistribute it 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.
**
**	Synfig is distributed in the hope that it will be useful,
**	but WITHOUT ANY WARRANTY; without even the implied warranty of
**	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
**	GNU General Public License for more details.
**
**	You should have received a copy of the GNU General Public License
**	along with Synfig.  If not, see <https://www.gnu.org/licenses/>.
**	\endlegal
**
** ========================================================================= */

/* === H E A D E R S ======================================================= */

#ifdef USING_PCH
#	include "pch.h"
#else
#ifdef HAVE_CONFIG_H
#	include <config.h>
#endif

#include <synfig/localization.h>
#include <synfig/general.h>
#include <synfig/color.h>

#include "trgt_gif.h"
#include <cstdio>
#endif

/* === M A C R O S ========================================================= */

using namespace synfig;

#define MAX_FRAME_RATE	(20.0)

/* === G L O B A L S ======================================================= */

SYNFIG_TARGET_INIT(gif);
SYNFIG_TARGET_SET_NAME(gif,"gif");
SYNFIG_TARGET_SET_EXT(gif,"gif");
SYNFIG_TARGET_SET_VERSION(gif,"0.1");

/* === M E T H O D S ======================================================= */

gif::gif(const synfig::filesystem::Path& filename_, const synfig::TargetParam & /* params */):
	bs(),
	filename(filename_),
	file( filename.u8string() == "-" ? stdout : synfig::SmartFILE(filename_, "wb") ),
	codesize(),
	rootsize(),
	nextcode(),
	table(nullptr),
	next(nullptr),
	node(nullptr),
	imagecount(0),
	cur_scanline(),
	lossy(true),
	multi_image(false),
	dithering(true),
	color_bits(8),
	iframe_density(30),
	loop_count(0x7fff),
	local_palette(true)
{ }

gif::~gif()
{
	if(file)
		fputc(';',file.get());	// Image terminator
}

bool
gif::set_rend_desc(RendDesc *given_desc)
{
	if(given_desc->get_frame_rate()>MAX_FRAME_RATE)
		given_desc->set_frame_rate(MAX_FRAME_RATE);

	desc=*given_desc;

	if(desc.get_frame_end()-desc.get_frame_start()>0)
	{
		multi_image=true;
		//set_remove_alpha();
		imagecount=desc.get_frame_end()-desc.get_frame_start();
	}
	else
		multi_image=false;
	return true;
}

bool
gif::init(synfig::ProgressCallback * /* cb */)
{
	int w=desc.get_w(),h=desc.get_h();

	if(!file)
	{
		synfig::error(strprintf(_("Unable to open \"%s\" for write access!"), filename.u8_str()));
		return false;
	}

	rootsize=color_bits;	// Size of pixel bits

	curr_frame.set_wh(w,h);
	prev_frame.set_wh(w,h);
	curr_surface.set_wh(w,h);
	curr_frame.clear();
	prev_frame.clear();
	curr_surface.clear();

	if(get_quality()>5)
		lossy=true;
	else
		lossy=false;

	// Output the header
	fprintf(file.get(),"GIF89a");
	fputc(w&0x000000ff,file.get());
	fputc((w&0x0000ff00)>>8,file.get());
	fputc(h&0x000000ff,file.get());
	fputc((h&0x0000ff00)>>8,file.get());
	if(!local_palette)
		fputc(0xF0+(rootsize-1),file.get());	// flags
	else
		fputc((0xF0+(rootsize-1))&~(1<<7),file.get());	// flags

	fputc(0,file.get());		// background color
	fputc(0,file.get());		// Pixel Aspect Ratio

	if(!local_palette)
	{
		curr_palette = Palette::grayscale(256/(1<<(8-rootsize))-1, 1);
		output_curr_palette();
	}

	if(loop_count && multi_image)
	{
		fputc(33,file.get()); // 33 (hex 0x21) GIF Extension code
		fputc(255,file.get()); // 255 (hex 0xFF) Application Extension Label
		fputc(11,file.get()); // 11 (hex (0x0B) Length of Application Block
		fprintf(file.get(),"NETSCAPE2.0");
		fputc(3,file.get()); // 3 (hex 0x03) Length of Data Sub-Block
		fputc(1,file.get()); // 1 (hex 0x01)
		fputc(loop_count&0x000000ff,file.get());
		fputc((loop_count&0x0000ff00)>>8,file.get());
		fputc(0,file.get()); // 0 (hex 0x00) a Data Sub-block Terminator.
	}

	return true;
}

void
gif::output_curr_palette()
{
	// Output the color table
	for(int i = 0; i < 256/(1<<(8-rootsize)); ++i) {
		if (i < (int)curr_palette.size()) {
			Color color = curr_palette[i].color.clamped();
			fputc((unsigned char)(color.get_r()*255.99), file.get());
			fputc((unsigned char)(color.get_g()*255.99), file.get());
			fputc((unsigned char)(color.get_b()*255.99), file.get());
		} else {
			fputc(255,file.get());
			fputc(0,file.get());
			fputc(255,file.get());
		}
	}
}

bool
gif::start_frame(synfig::ProgressCallback *callback)
{
//	int
//		w=desc.get_w(),
//		h=desc.get_h();

	if(!file)
	{
		if(callback)callback->error(std::string("BUG:")+_("Description not set!"));
		return false;
	}

	if (callback) callback->task(filename.u8string() + strprintf(" %d", imagecount));



	return true;
}

void
gif::end_frame()
{
	int w = desc.get_w(), h = desc.get_h();
	unsigned int value;
	int delaytime = round_to_int(100.0/desc.get_frame_rate());

	bool build_off_previous(multi_image);

	Palette prev_palette(curr_palette);

	// Fill in the background color
	if(get_alpha_mode()==TARGET_ALPHA_MODE_KEEP)
	{
		Surface::alpha_pen pen(curr_surface.begin(),1.0,Color::BLEND_BEHIND);
		pen.set_value(get_canvas()->rend_desc().get_bg_color());
		for(int y=0;y<curr_surface.get_h();y++,pen.inc_y())
		{
			int x;
			for(x=0;x<curr_surface.get_w();x++,pen.inc_x())
			{
				if(pen.get_value().get_a()>0.1)
					pen.put_value();
				else
					pen[0][0]=Color::alpha();
			}
			pen.dec_x(x);
		}
	}

	if(local_palette)
	{
		curr_palette = Palette(curr_surface, 256/(1<<(8-rootsize)) - build_off_previous - 1, Gamma());
		synfig::info("curr_palette.size()=%d",curr_palette.size());
	}

	int transparent_index = curr_palette.find_closest(Color(1,0,1,0), Gamma()) - curr_palette.begin();
	bool has_transparency = curr_palette[transparent_index].color.get_a()<=0.00001;

	if(has_transparency)
		build_off_previous=false;

	if(build_off_previous)
	{
		transparent_index=0;
		has_transparency=true;
	}

#define DISPOSE_UNDEFINED			(0)
#define DISPOSE_NONE				(1<<2)
#define DISPOSE_RESTORE_BGCOLOR		(2<<2)
#define DISPOSE_RESTORE_PREVIOUS	(3<<2)
	int gec_flags(0);
	if(build_off_previous)
		gec_flags|=DISPOSE_NONE;
	else
		gec_flags|=DISPOSE_RESTORE_BGCOLOR;
	if(has_transparency)
		gec_flags|=1;

	// output the Graphic Control Extension
	fputc(0x21,file.get()); // Extension introducer
	fputc(0xF9,file.get()); // Graphic Control Label
	fputc(4,file.get()); // Block Size
	fputc(gec_flags,file.get()); // Flags (Packed Fields)
	fputc(delaytime&0x000000ff,file.get()); // Delay Time (MSB)
	fputc((delaytime&0x0000ff00)>>8,file.get()); // Delay Time (LSB)
	fputc(transparent_index,file.get()); // Transparent Color Index
	fputc(0,file.get()); // Block Terminator

	// output the image header
	fputc(',',file.get());
	fputc(0,file.get());	// image left
	fputc(0,file.get());	// image left
	fputc(0,file.get());	// image top
	fputc(0,file.get());	// image top
	fputc(w&0x000000ff,file.get());
	fputc((w&0x0000ff00)>>8,file.get());
	fputc(h&0x000000ff,file.get());
	fputc((h&0x0000ff00)>>8,file.get());
	if(local_palette)
		fputc(0x80|(rootsize-1),file.get());	// flags
	else
		fputc(0x00+ rootsize-1,file.get());	// flags


	if(local_palette)
	{
		Palette out(curr_palette);

		if(build_off_previous)
			curr_palette.insert(curr_palette.begin(),Color(1,0,1,0));
		output_curr_palette();
		curr_palette=out;
	}

	bs=bitstream(file);

	// Prepare ourselves for LZW compression
	codesize=rootsize+1;
	nextcode=(1<<rootsize)+2;
	table=lzwcode::NewTable((1<<rootsize));
	node=table;

	// Output the rootsize
	fputc(rootsize,file.get());	// rootsize;

	// Push a table reset into the bitstream
	bs.push_value(1<<rootsize,codesize);

	for(int cur_scanline=0;cur_scanline<desc.get_h();cur_scanline++)
	{
		//color_to_pixelformat(curr_frame[cur_scanline], curr_surface[cur_scanline], PF_GRAY, &gamma(), desc.get_w());

		// Now we compress it!
		for(int i=0; i < w; ++i)
		{
			Color color(curr_surface[cur_scanline][i].clamped());
			Palette::iterator iter(curr_palette.find_closest(color, Gamma()));

			if(dithering)
			{
				Color error(color-iter->color);
				//error*=0.25;
				if(curr_surface.get_h()>cur_scanline+1)
				{
					curr_surface[cur_scanline+1][i-1]  += error * ((float)3/(float)16);
					curr_surface[cur_scanline+1][i]    += error * ((float)5/(float)16);
					if(curr_surface.get_w()>i+1)
						curr_surface[cur_scanline+1][i+1]  += error * ((float)1/(float)16);
				}
				if(curr_surface.get_w()>i+1)
					curr_surface[cur_scanline][i+1]    += error * ((float)7/(float)16);
			}

			curr_frame[cur_scanline][i]=iter-curr_palette.begin();

			value=curr_frame[cur_scanline][i];
			if(build_off_previous)
				value++;
			if(value>(unsigned)(1<<rootsize)-1)
				value=(1<<rootsize)-1;

			// If the pixel is the same as the one that
			// is already there, then we should make it
			// transparent
			if(build_off_previous)
			{
				if(lossy)
				{

					// Lossy
					if ((!prev_palette.empty() &&
						std::fabs( ( iter->color-prev_palette[prev_frame[cur_scanline][i]-1].color ).get_y() ) > (1.0/16.0)) ||
//						abs((int)value-(int)prev_frame[cur_scanline][i])>2||
//						(value<=2 && value!=prev_frame[cur_scanline][i]) ||
						(imagecount%iframe_density)==0 || imagecount==desc.get_frame_end()-1 ) // lossy version
						prev_frame[cur_scanline][i]=value;
					else
					{
						prev_frame[cur_scanline][i]=value;
						value=0;
					}
				}
				else
				{
					// lossless version
					if(value!=prev_frame[cur_scanline][i])
						prev_frame[cur_scanline][i]=value;
					else
						value=0;
				}
			}
			else
			prev_frame[cur_scanline][i]=value;

			next=node->FindCode(value);
			if(next)
				node=next;
			else
			{
				node->AddNode(nextcode, value);
				bs.push_value(node->code, codesize);
				node = table->FindCode(value);

				// Check to see if we need to increase the codesize
				if (nextcode == ( 1 << codesize))
					codesize += 1;

				nextcode += 1;

				// check to see if we have filled up the table
				if (nextcode == 4096)
				{
					// output the clear code: make sure to use the current
					// codesize
					bs.push_value((unsigned) 1 << rootsize, codesize);

					delete table;
					table = lzwcode::NewTable((1<<rootsize));
					codesize = rootsize + 1;
					nextcode = (1 << rootsize) + 2;

					// since we have a new table, need the correct prefix
					node = table->FindCode(value);
				}
			}
		}
	}





	// Push the last code onto the bitstream
	bs.push_value(node->code,codesize);

	// Push a end-of-stream code onto the bitstream
	bs.push_value((1<<rootsize)+1,codesize);

	// Make sure everything is dumped out
	bs.dump();

	delete table;

	fputc(0,file.get());		// Block terminator

	fflush(file.get());
	imagecount++;
}

synfig::Color*
gif::start_scanline(int scanline)
{
	cur_scanline=scanline;
	return curr_surface[scanline];
}

bool
gif::end_scanline()
{
	if(!file)
		return false;

//	int w=desc.get_w(),i;
//	unsigned int value;


	return true;
}
