#include	"dat.h"
#include	"fns.h"
#include	"error.h"

typedef struct Join Join;
struct Join
{
	Chan *c;
	Join *next;
};

enum
{
	Qdir,
	Qjoinfile,
};

Dirtab joindir[] =
{
	".",		{Qdir,0,QTDIR},	0,		DMDIR|0500,
	"new",		{Qjoinfile},	0,		0660,
};

static void
joinfree(Join *j)
{
	if(j == nil)
		return;
	joinfree(j->next);
	cclose(j->c);
	free(j);
}

static Chan*
joinattach(char *spec)
{
	return devattach('δ', spec);
}

static Walkqid*
joinwalk(Chan *c, Chan *nc, char **name, int nname)
{
	return devwalk(c, nc, name, nname, joindir, nelem(joindir), devgen);
}

static int
joinstat(Chan *c, uchar *db, int n)
{
        return devstat(c, db, n, joindir, nelem(joindir), devgen);
}

static Chan*
joinopen(Chan *c, int omode)
{
	return devopen(c, omode, joindir, nelem(joindir), devgen);
}

static void
joinclose(Chan *c)
{
	joinfree(c->aux);
	c->aux = nil;
}

static long
joinread(Chan *c, void *va, long n, vlong off)
{
	Join *j;
	long l;


	if(c->qid.type == QTDIR)
		return devdirread(c, va, n, joindir, nelem(joindir), devgen);

	l = 0;
	while(c->aux != nil) {
		j = c->aux;
		l = devtab[j->c->type]->read(j->c, va, n, off);
		if(l != 0)
			break;

		c->aux = j->next;
		cclose(j->c);
		free(j);
	}
	return l;
}

static long
joinwrite(Chan *c, void *va, long n, vlong off)
{
	char buf[32];
	int fd;
	Chan *jc;
	Join *j;
	Join *nj;

	if(c->qid.type == QTDIR)
		error(Eisdir);

	if(n >= sizeof buf+1)
		error(Ebadarg);
	memmove(buf, va, n);
	buf[n] = 0;
	fd = atoi(buf);
	jc = fdtochan(up->env->fgrp, fd, -1, 0, 1);
	nj = malloc(sizeof nj[0]);
	nj->c = jc;
	nj->next = nil;
	if(c->aux == nil) {
		c->aux = nj;
	} else {
		for(j = c->aux; j->next != nil; j = j->next)
			{}
		j->next = nj;
	}
	return n;
}


Dev joindevtab = {
	'δ',
	"join",

	devinit,
	joinattach,
	joinwalk,
	joinstat,
	joinopen,
	devcreate,
	joinclose,
	joinread,
	devbread,
	joinwrite,
	devbwrite,
	devremove,
	devwstat,
};