#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>
#include <fcntl.h>
#include <unistd.h>
#include <SDL.h>
#include "common.h"

enum {
	Fmtk1,
	Fmtk8,
};

static char *sfmt[] = {
	[Fmtk1] = "k1",
	[Fmtk8] = "k8",
};

int
savesubfont(uint8_t *pix, int w, int h, int ascent, int scale, Fontchar *cs, int nc, char *path)
{
	int f, sz, i, fmt, pixsz, x, y;
	uint8_t *b, *p, t;
	Fontchar *c;

	if(h < 1){
		fprintf(stderr, "%s: zero height subfont\n", path);
		return -1;
	}
	for(y = h-1; y > 0; y--){
		for(x = 0; x < w; x++){
			if(pix[y*w + x] != 0)
				break;
		}
		if(x < w)
			break;
	}
	h = y+1;

	if(scale > 1){
		b = p = malloc(w*scale*h*scale);
		for(y = 0; y < h; y++){
			for(x = 0; x < w; x++){
				for(i = 0; i < scale; i++)
					*p++ = pix[y*w + x];
			}
			for(i = 0; i < scale-1; i++){
				memmove(p, p-w*scale, w*scale);
				p += w*scale;
			}
		}
		pix = b;
		w *= scale;
		h *= scale;
		ascent *= scale;
	}

	pixsz = w*h;
	fmt = Fmtk8;
	for(i = 0; i < pixsz && (pix[i] == 0x00 || pix[i] == 0xff); i++);
	if(i == pixsz){
		pixsz = 0;
		fmt = Fmtk1;
		p = pix;
		for(y = 0; y < h; y++){
			b = pix + y*w;
			for(x = 0; x < w; x += 8){
				t = 0;
				for(i = 0; i < 8; i++){
					t <<= 1;
					if(x+i < w)
						t |= (*b++ & 1);
				}
				*p++ = t;
				pixsz++;
			}
		}
	}

	b = NULL;
	sz = 6*(nc+1);
	if((f = open(path, O_CREAT|O_TRUNC|O_WRONLY|O_CLOEXEC, 0644)) < 0 ||
	   dprintf(f, "%11s %11d %11d %11d %11d ", sfmt[fmt], 0, 0, w, h) < 0 ||
	   write(f, pix, pixsz) != pixsz ||
	   dprintf(f, "%11d %11d %11d ", nc, h, ascent) < 0 ||
	   (b = p = malloc(sz)) == NULL)
		goto err;

	for(i = 0; i < nc; i++){
		c = cs+i;
		*p++ = (c->x * scale) >> 0;
		*p++ = (c->x * scale) >> 8;
		*p++ = c->top * scale;
		*p++ = c->bottom * scale;
		*p++ = c->left * scale;
		*p++ = c->width * scale;
	}
	*p++ = w;
	*p++ = w >> 8;
	*p++ = 0;
	*p++ = 0;
	*p++ = 0;
	*p++ = 0;

	if(write(f, b, sz) != sz)
		goto err;
	free(b);
	if(scale > 1)
		free(pix);
	close(f);
	return 0;

err:
	perror(path);
	if(f >= 0)
		close(f);
	free(b);
	if(scale > 1)
		free(pix);
	return -1;
}