#include <u.h>
#include <libc.h>
#include <auth.h>
#include <fcall.h>
#include <thread.h>
#include <9p.h>

#define min(a, b) ((a) < (b) ? (a) : (b))

static char Eim[] = "imaginary result";
char buf[1024];

void
fsread(Req *r)
{
	int count;

	count = min(r->ifcall.count, strlen(buf));
	if(r->ifcall.offset >= count){
		r->ofcall.count = 0;
		respond(r, nil);
		return;
	}
	memmove(r->ofcall.data, buf, count);
	r->ofcall.count = count;
	respond(r, nil);
}

void
fswrite(Req *r)
{
	double in, n;

	in = strtod(r->ifcall.data, nil);
	if(in < 0){
		respond(r, Eim);
		return;
	}
	n = sqrt(in);
	snprint(buf, sizeof buf, "%g\n", n);
	r->fid->file->length = strlen(buf);
	r->ofcall.count = r->ifcall.count;
	respond(r, nil);
}

Srv fs = {
	.read	= fsread,
	.write	= fswrite,
};

void
usage(void)
{
	fprint(2, "usage: sqrtfs [-D] [-s srvname] [-m mtpt]\n");
	exits("usage");
}

void
main(int argc, char *argv[])
{
	File *f;
	char *srvname, *mtpt;

	srvname = nil;
	mtpt = "/n/sqrt";
	ARGBEGIN{
	case 'D':
		chatty9p++;
		break;
	case 's':
		srvname = EARGF(usage());
		break;
	case 'm':
		mtpt = EARGF(usage());
		break;
	default:
		usage();
	}ARGEND;
	if(argc != 0)
		usage();
	fs.tree = alloctree(nil, nil, DMDIR|0777, nil);
	if((f = createfile(fs.tree->root, "sqrt", nil, 0666, nil)) == nil)
		sysfatal("createfile: %r");
	snprint(buf, sizeof buf, "%d\n", 0);
	f->length = 1;
	postmountsrv(&fs, srvname, mtpt, MREPL|MCREATE);
	exits(0);
}