#include <stdio.h>
#include <math.h>
#include <string.h>
#include <stdlib.h>
#include "gd.h"

#define TRUE 1
#define FALSE 0

/* Exported functions: */
extern void gdImageGd (gdImagePtr im, FILE * out);


/* Use this for commenting out debug-print statements. */
/* Just use the first '#define' to allow all the prints... */
/*#define GD2_DBG(s) (s) */
#define GD2_DBG(s)

/* */
/* Shared code to read color tables from gd file. */
/* */
int _gdGetColors (gdIOCtx * in, gdImagePtr im, int gd2xFlag)
{
	int i;
	if (gd2xFlag) {
		int trueColorFlag;
		if (!gdGetByte(&trueColorFlag, in)) {
			goto fail1;
		}
		/* 2.0.12: detect bad truecolor .gd files created by pre-2.0.12.
		 * Beginning in 2.0.12 truecolor is indicated by the initial 2-byte
		 * signature.
		 */
		if (trueColorFlag != im->trueColor) {
			goto fail1;
		}
		/* This should have been a word all along */
		if (!im->trueColor) {
			if (!gdGetWord(&im->colorsTotal, in)) {
				goto fail1;
			}
			if (im->colorsTotal > gdMaxColors) {
				goto fail1;
			}
		}
		/* Int to accommodate truecolor single-color transparency */
		if (!gdGetInt(&im->transparent, in)) {
			goto fail1;
		}
	} else {
		if (!gdGetByte(&im->colorsTotal, in)) {
			goto fail1;
		}
		if (!gdGetWord(&im->transparent, in)) {
			goto fail1;
		}
		if (im->transparent == 257) {
			im->transparent = (-1);
		}
	}

	GD2_DBG(printf("Palette had %d colours (T=%d)\n", im->colorsTotal, im->transparent));

	if (im->trueColor) {
		return TRUE;
	}

	for (i = 0; i < gdMaxColors; i++) {
		if (!gdGetByte(&im->red[i], in)) {
			goto fail1;
		}
		if (!gdGetByte(&im->green[i], in)) {
			goto fail1;
		}
		if (!gdGetByte(&im->blue[i], in)) {
			goto fail1;
		}
		if (gd2xFlag) {
			if (!gdGetByte(&im->alpha[i], in)) {
				goto fail1;
			}
		}
	}

	for (i = 0; i < im->colorsTotal; i++) {
		im->open[i] = 0;
	}

	return TRUE;
fail1:
	return FALSE;
}

/* */
/* Use the common basic header info to make the image object. */
/* */
static gdImagePtr _gdCreateFromFile (gdIOCtx * in, int *sx, int *sy)
{
	gdImagePtr im;
	int gd2xFlag = 0;
	int trueColorFlag = 0;

	if (!gdGetWord(sx, in)) {
		goto fail1;
	}
	if (*sx == 65535 || *sx == 65534) {
		/* This is a gd 2.0 .gd file */
		gd2xFlag = 1;
		/* 2.0.12: 65534 signals a truecolor .gd file. There is a slight redundancy here but we can live with it. */
		if (*sx == 65534) {
			trueColorFlag = 1;
		}
		if (!gdGetWord(sx, in)) {
			goto fail1;
		}
	}
	if (!gdGetWord(sy, in)) {
		goto fail1;
	}

	GD2_DBG(printf("Image is %dx%d\n", *sx, *sy));

	if (trueColorFlag) {
		im = gdImageCreateTrueColor(*sx, *sy);
	} else {
		im = gdImageCreate(*sx, *sy);
	}
	if(!im) {
		goto fail1;
	}
	if (!_gdGetColors(in, im, gd2xFlag)) {
		goto fail2;
	}

	return im;
fail2:
	gdImageDestroy(im);
fail1:
	return 0;
}

gdImagePtr gdImageCreateFromGd (FILE * inFile)
{
	gdImagePtr im;
	gdIOCtx *in;

	in = gdNewFileCtx(inFile);
	im = gdImageCreateFromGdCtx(in);

	in->gd_free(in);

	return im;
}

gdImagePtr gdImageCreateFromGdPtr (int size, void *data)
{
	gdImagePtr im;
	gdIOCtx *in = gdNewDynamicCtxEx(size, data, 0);
	im = gdImageCreateFromGdCtx(in);
	in->gd_free(in);

	return im;
}

gdImagePtr gdImageCreateFromGdCtx (gdIOCtxPtr in)
{
	int sx, sy;
	int x, y;
	gdImagePtr im;

	/* Read the header */
	im = _gdCreateFromFile(in, &sx, &sy);

	if (im == NULL) {
		goto fail1;
	}

	/* Then the data... */
	/* 2.0.12: support truecolor properly in .gd as well as in .gd2. Problem reported by Andreas Pfaller. */
	if (im->trueColor) {
		for (y = 0; y < sy; y++) {
			for (x = 0; x < sx; x++) {
				int pix;
				if (!gdGetInt(&pix, in)) {
					goto fail2;
				}
				im->tpixels[y][x] = pix;
			}
		}
	} else {
		for (y = 0; y < sy; y++) {
			for (x = 0; x < sx; x++) {
				int ch;
				ch = gdGetC(in);
				if (ch == EOF) {
					goto fail2;
				}
				/* ROW-MAJOR IN GD 1.3 */
				im->pixels[y][x] = ch;
			}
		}
	}

	return im;

fail2:
	gdImageDestroy (im);
fail1:
	return 0;
}

void _gdPutColors (gdImagePtr im, gdIOCtx * out)
{
	int i;

	gdPutC(im->trueColor, out);
	if (!im->trueColor) {
		gdPutWord(im->colorsTotal, out);
	}
	gdPutInt(im->transparent, out);
	if (!im->trueColor) {
		for (i = 0; i < gdMaxColors; i++) {
			gdPutC((unsigned char) im->red[i], out);
			gdPutC((unsigned char) im->green[i], out);
			gdPutC((unsigned char) im->blue[i], out);
			gdPutC((unsigned char) im->alpha[i], out);
		}
	}
}

static void _gdPutHeader (gdImagePtr im, gdIOCtx * out)
{
	/* 65535 indicates this is a gd 2.x .gd file.
	 * 2.0.12: 65534 indicates truecolor.
	 */
	if (im->trueColor) {
		gdPutWord(65534, out);
	} else {
		gdPutWord(65535, out);
	}
	gdPutWord(im->sx, out);
	gdPutWord(im->sy, out);

	_gdPutColors(im, out);
}

static void _gdImageGd (gdImagePtr im, gdIOCtx * out)
{
	int x, y;

	_gdPutHeader(im, out);

	for (y = 0; y < im->sy; y++) {
		for (x = 0; x < im->sx; x++) {
			/* ROW-MAJOR IN GD 1.3 */
			if (im->trueColor) {
				gdPutInt(im->tpixels[y][x], out);
			} else {
				gdPutC((unsigned char) im->pixels[y][x], out);
			}
		}
	}
}

void gdImageGd (gdImagePtr im, FILE * outFile)
{
	gdIOCtx *out = gdNewFileCtx(outFile);
	_gdImageGd(im, out);
	out->gd_free(out);
}

void *gdImageGdPtr (gdImagePtr im, int *size)
{
	void *rv;
	gdIOCtx *out = gdNewDynamicCtx(2048, NULL);
	_gdImageGd(im, out);
	rv = gdDPExtractData(out, size);
	out->gd_free(out);
	return rv;
}
