#include "image.h"
#include <memdraw.h>
#include <bio.h>

/* fd -> cat -> p[1] -> p[0] */
int
hdrcat(int fd, ImgHdr h)
{
	int p[2];

	if(pipe(p) < 0) {
		werrstr("pipe: %r");
		return -1;
	}

	switch(rfork(RFPROC|RFREND|RFFDG|RFNAMEG|RFNOWAIT)) {
	case -1:
		close(p[0]);
		close(p[1]);
		werrstr("fork: %r");
		return -1;

	case 0:
		close(p[0]);
		dup(p[1], 1);
		dup(fd, 0);

		print("%H", h);
		execl("/bin/cat", "cat", nil);
		sysfatal("exec cat: %r");
	}

	close(p[1]);
	return p[0];
}

/* fd -> decompress -> p[1] -> p[0] */
int
_decompress(int fd)
{
	int p[2];

	if(pipe(p) < 0) {
		werrstr("pipe: %r");
		return -1;
	}

	switch(rfork(RFPROC|RFREND|RFFDG|RFNAMEG|RFNOWAIT)) {
	case -1:
		close(p[0]);
		close(p[1]);
		werrstr("fork: %r");
		return -1;

	case 0:
		close(p[0]);
		dup(p[1], 1);
		dup(fd, 0);

		execl("/bin/image/decompress", "image/decompress", nil);
		sysfatal("exec decompress: %r");
	}

	close(p[1]);
	return p[0];
}

int
decompress(int fd, ImgHdr *h)
{
	if((fd = hdrcat(fd, *h)) < 0) {
		werrstr("decompress: hdrcat: %r");
		return -1;
	}
	if((fd = _decompress(fd)) < 0)
		sysfatal("decompress: _: %r");
	if(readimghdr(fd, h) < 0)
		sysfatal("decompress: header: %r");
	return fd;
}

int
linesz(ImgHdr h)
{
	return Dx(h.r) * chantodepth(h.chan)/8;
}

void
usage(void)
{
	fprint(2, "usage: %s <image.bit\n", argv0);
	exits("usage");
}

void
main(int argc, char **argv)
{
	ImgHdr hdst, hsrc;
	int fd;
	Memimage *dstline, *srcline;
	Biobuf bdst, bsrc;
	uchar *buf;
	int y, n;

	ARGBEGIN {
	default:
		usage();
	} ARGEND
	if(argc != 0)
		usage();

	memimageinit();
	if(fmtinstall('H', Hfmt) < 0)
		sysfatal("fmtinstall");

	if(readimghdr(0, &hsrc) < 0)
		sysfatal("header: %r");
	if(hsrc.chan == RGBA32) {
		fprint(1, "%H", hsrc);
		execl("/bin/cat", "cat", nil);
		sysfatal("exec cat: %r");
	}
	if(hsrc.compressed) {
		if((fd = decompress(0, &hsrc)) < 0)
			sysfatal("decompress: %r");
		dup(fd, 0);
		close(fd);
	}
	hdst = hsrc;
	hdst.chan = RGBA32;

	if((dstline = allocmemimage(Rect(0, 0, Dx(hdst.r), 1), hdst.chan)) == nil
		|| (srcline = allocmemimage(Rect(0, 0, Dx(hsrc.r), 1), hsrc.chan)) == nil ) {
		sysfatal("allocmemimage: %r");
		return;
	}
	if((buf = malloc(linesz(hdst) > linesz(hsrc) ? linesz(hdst) : linesz(hsrc))) == nil)
		sysfatal("alloc buf: %r");

	if(Binit(&bsrc, 0, OREAD) < 0 || Binit(&bdst, 1, OWRITE) < 0)
		sysfatal("Binit");

	Bprint(&bdst, "%H", hdst);
	for(y = 0; y < Dy(hsrc.r); y++) {
		if((n = Bread(&bsrc, buf, linesz(hsrc))) != linesz(hsrc)) {
			if(n == 0)
				werrstr("eof");
			sysfatal("read src: line %d/%d: %d/%d: %r", y, Dy(hsrc.r), n, linesz(hsrc));
		}
		if(loadmemimage(srcline, srcline->r, buf, linesz(hsrc)) < 0)
			sysfatal("load src");
		memimagedraw(dstline, dstline->r, srcline, ZP, nil, ZP, S);
		if(unloadmemimage(dstline, dstline->r, buf, linesz(hdst)) < 0)
			sysfatal("unload dst");
		if(Bwrite(&bdst, buf, linesz(hdst)) != linesz(hdst))
			sysfatal("write dst: %r");
	}

	exits(nil);
}