/*
 *  ircd-ratbox: A slightly useful ircd.
 *  whowas.c: WHOWAS user cache.
 *
 *  Copyright (C) 1990 Jarkko Oikarinen and University of Oulu, Co Center
 *  Copyright (C) 1996-2002 Hybrid Development Team
 *  Copyright (C) 2002-2005 ircd-ratbox development team
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307
 *  USA
 *
 */

#include "stdinc.h"

#include "whowas.h"
#include "client.h"
#include "common.h"
#include "hash.h"
#include "match.h"
#include "ircd.h"
#include "ircd_defs.h"
#include "numeric.h"
#include "s_serv.h"
#include "s_user.h"
#include "send.h"
#include "s_conf.h"
#include "scache.h"

/* internally defined function */
static void add_whowas_to_clist(struct Whowas **, struct Whowas *);
static void del_whowas_from_clist(struct Whowas **, struct Whowas *);
static void add_whowas_to_list(struct Whowas **, struct Whowas *);
static void del_whowas_from_list(struct Whowas **, struct Whowas *);

struct Whowas WHOWAS[NICKNAMEHISTORYLENGTH];
struct Whowas *WHOWASHASH[WW_MAX];

static int whowas_next = 0;

unsigned int hash_whowas_name(const char *name)
{
    return fnv_hash_upper((const unsigned char *) name, WW_MAX_BITS);
}

void add_history(struct Client *client_p, int online)
{
    struct Whowas *who = &WHOWAS[whowas_next];

    s_assert(NULL != client_p);

    if(client_p == NULL)
        return;

    if(who->hashv != -1) {
        if(who->online)
            del_whowas_from_clist(&(who->online->whowas), who);
        del_whowas_from_list(&WHOWASHASH[who->hashv], who);
    }
    who->hashv = hash_whowas_name(client_p->name);
    who->logoff = rb_current_time();
    /*
     * NOTE: strcpy ok here, the sizes in the client struct MUST
     * match the sizes in the whowas struct
     */
    rb_strlcpy(who->name, client_p->name, sizeof(who->name));
    strcpy(who->username, client_p->username);
    strcpy(who->hostname, client_p->host);
    strcpy(who->realname, client_p->info);
    strcpy(who->suser, client_p->user->suser);
    if (!EmptyString(client_p->sockhost) && strcmp(client_p->sockhost, "0") && show_ip(NULL, client_p))
        strcpy(who->sockhost, client_p->sockhost);
    else
        who->sockhost[0] = '\0';

    who->servername = scache_get_name(client_p->servptr->serv->nameinfo);

    if(online) {
        who->online = client_p;
        add_whowas_to_clist(&(client_p->whowas), who);
    } else
        who->online = NULL;
    add_whowas_to_list(&WHOWASHASH[who->hashv], who);
    whowas_next++;
    if(whowas_next == NICKNAMEHISTORYLENGTH)
        whowas_next = 0;
}

void off_history(struct Client *client_p)
{
    struct Whowas *temp, *next;

    for (temp = client_p->whowas; temp; temp = next) {
        next = temp->cnext;
        temp->online = NULL;
        del_whowas_from_clist(&(client_p->whowas), temp);
    }
}

struct Client *get_history(const char *nick, time_t timelimit)
{
    struct Whowas *temp;
    int blah;

    timelimit = rb_current_time() - timelimit;
    blah = hash_whowas_name(nick);
    temp = WHOWASHASH[blah];
    for (; temp; temp = temp->next) {
        if(irccmp(nick, temp->name))
            continue;
        if(temp->logoff < timelimit)
            continue;
        return temp->online;
    }
    return NULL;
}

void count_whowas_memory(size_t * wwu, size_t * wwum)
{
    *wwu = NICKNAMEHISTORYLENGTH;
    *wwum = NICKNAMEHISTORYLENGTH * sizeof(struct Whowas);
}

void
initwhowas()
{
    int i;

    for (i = 0; i < NICKNAMEHISTORYLENGTH; i++) {
        memset((void *) &WHOWAS[i], 0, sizeof(struct Whowas));
        WHOWAS[i].hashv = -1;
    }
    for (i = 0; i < WW_MAX; i++)
        WHOWASHASH[i] = NULL;
}


static void
add_whowas_to_clist(struct Whowas **bucket, struct Whowas *whowas)
{
    whowas->cprev = NULL;
    if((whowas->cnext = *bucket) != NULL)
        whowas->cnext->cprev = whowas;
    *bucket = whowas;
}

static void
del_whowas_from_clist(struct Whowas **bucket, struct Whowas *whowas)
{
    if(whowas->cprev)
        whowas->cprev->cnext = whowas->cnext;
    else
        *bucket = whowas->cnext;
    if(whowas->cnext)
        whowas->cnext->cprev = whowas->cprev;
}

static void
add_whowas_to_list(struct Whowas **bucket, struct Whowas *whowas)
{
    whowas->prev = NULL;
    if((whowas->next = *bucket) != NULL)
        whowas->next->prev = whowas;
    *bucket = whowas;
}

static void
del_whowas_from_list(struct Whowas **bucket, struct Whowas *whowas)
{
    if(whowas->prev)
        whowas->prev->next = whowas->next;
    else
        *bucket = whowas->next;
    if(whowas->next)
        whowas->next->prev = whowas->prev;
}
