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

typedef struct Node Node;
typedef struct Node {
	ulong id;
	char *u, *g;
	Node *l, *r;
};

static Node *Base = nil;

static Node *
addmap(Node *n, ulong id, char *u, char *g)
{
	if (n == nil){
		if ((n = emalloc9p(sizeof(Node))) == nil)
			sysfatal("No memory");
		n->id = id;
		n->u = estrdup9p(u);
		n->g = estrdup9p(g);
		n->l = n->r = nil;
	} else
	if (n->id == id)
		sysfatal("duplicate ID - programmer error");
	else if (n->id < id)
		n->l = addmap(n->l, id, u, g);
	else
		n->r = addmap(n->r, id, u, g);
	return n;
}

static int 
lookmap(Node *n, ulong id, char **u, char **g)
{
	if (n != nil) {
		if (id == n->id){
			if (u)
				*u = n->u;
			if (g)
				*g = n->g;
			return 0;
		}
		if (lookmap(n->l, id, u, g) != -1)
			return 0;
		if (lookmap(n->r, id, u, g) != -1)
			return 0;
	}
	return -1;
}

/*
 * pick the first group the user is in,
 * avoiding 'everyone' if possible.
 */
static ulong
user2gid(Session *s, char *usr)
{
	ulong maybe, gid;
	int more, seq, type, flags;
	uchar buf[PROPLEN], *p;
	char group[OBJNAMLEN];

	maybe = 0;
	for (more = 1, seq = 1; more; seq++) {
		if (ReadPropertyValue(s, usr, OTuser, "groups_i'm_in", seq,
	    	    buf, &more, &flags) == -1)
			break;
		p = buf;
		while(1){
			gid  = *p++ << 24;
			gid |= *p++ << 16;
			gid |= *p++ << 8;
			gid |= *p++;

			if (GetBinderyObjectName(s, gid, group, &type) != 0)
				break;
			if (*group){
				maybe = gid;
				if (strcmp(strlwr(group), "everyone") != 0) 
					return gid;
			}
		}
	}

	return maybe;
}

void
uid2names(Session *s, ulong uid, char **usr, char **grp)
{
	int type;
	ulong gid;
	static char user[OBJNAMLEN];
	static char group[OBJNAMLEN];

	if (lookmap(Base, uid, usr, grp) == 0)
		return;

	if (GetBinderyObjectName(s, uid, user, &type) == -1)
		if (uid == 0)
			strcpy(user, "none");
		else
			snprint(user, sizeof(user), "%lux", uid);

	gid = user2gid(s, user);

	if (GetBinderyObjectName(s, gid, group, &type) == -1)
		if (gid == 0)
			strcpy(group, "none");
		else
			snprint(group, sizeof(group), "%lux", gid);

	strlwr(user);
	strlwr(group);
	Base = addmap(Base, uid, user, group);
	if (usr)
		*usr = user;
	if (grp)
		*grp = group;
}