/*
 *  charybdis: A slightly useful ircd.
 *  supported.c: isupport (005) numeric
 *
 * Copyright (C) 2006 Jilles Tjoelker
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are
 * met:
 *
 * 1.Redistributions of source code must retain the above copyright notice,
 *   this list of conditions and the following disclaimer.
 * 2.Redistributions in binary form must reproduce the above copyright
 *   notice, this list of conditions and the following disclaimer in the
 *   documentation and/or other materials provided with the distribution.
 * 3.The name of the author may not be used to endorse or promote products
 *   derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT,
 * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
 * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 *
 */

/* From the old supported.h which is
 *  Copyright (C) 1996-2002 Hybrid Development Team
 *  Copyright (C) 2002-2004 ircd-ratbox development team
 */
/*
 * - from mirc's versions.txt
 *
 *  mIRC now supports the numeric 005 tokens: CHANTYPES=# and
 *  PREFIX=(ohv)@%+ and can handle a dynamic set of channel and
 *  nick prefixes.
 *
 *  mIRC assumes that @ is supported on all networks, any mode
 *  left of @ is assumed to have at least equal power to @, and
 *  any mode right of @ has less power.
 *
 *  mIRC has internal support for @%+ modes.
 *
 *  $nick() can now handle all mode letters listed in PREFIX.
 *
 *  Also added support for CHANMODES=A,B,C,D token (not currently
 *  supported by any servers), which lists all modes supported
 *  by a channel, where:
 *
 *    A = modes that take a parameter, and add or remove nicks
 *        or addresses to a list, such as +bIe for the ban,
 *        invite, and exception lists.
 *
 *    B = modes that change channel settings, but which take
 *        a parameter when they are set and unset, such as
 *        +k key, and -k key.
 *
 *    C = modes that change channel settings, but which take
 *        a parameter only when they are set, such as +l N,
 *        and -l.
 *
 *    D = modes that change channel settings, such as +imnpst
 *        and take no parameters.
 *
 *  All unknown/unlisted modes are treated as type D.
 */

#include "stdinc.h"
#include "client.h"
#include "common.h"
#include "numeric.h"
#include "ircd.h"
#include "s_conf.h"
#include "supported.h"
#include "chmode.h"

rb_dlink_list isupportlist;

struct isupportitem {
    const char *name;
    const char *(*func)(const void *);
    const void *param;
    rb_dlink_node node;
};

void
add_isupport(const char *name, const char *(*func)(const void *), const void *param)
{
    struct isupportitem *item;

    item = rb_malloc(sizeof(struct isupportitem));
    item->name = name;
    item->func = func;
    item->param = param;
    rb_dlinkAddTail(item, &item->node, &isupportlist);
}

const void *
change_isupport(const char *name, const char *(*func)(const void *), const void *param)
{
    rb_dlink_node *ptr;
    struct isupportitem *item;
    const void *oldvalue = NULL;

    RB_DLINK_FOREACH(ptr, isupportlist.head) {
        item = ptr->data;

        if (!strcmp(item->name, name)) {
            oldvalue = item->param;

            // item->name = name;
            item->func = func;
            item->param = param;

            break;
        }
    }

    return oldvalue;
}

void
delete_isupport(const char *name)
{
    rb_dlink_node *ptr, *next_ptr;
    struct isupportitem *item;

    RB_DLINK_FOREACH_SAFE(ptr, next_ptr, isupportlist.head) {
        item = ptr->data;

        if (!strcmp(item->name, name)) {
            rb_dlinkDelete(ptr, &isupportlist);
            rb_free(item);
        }
    }
}

/* XXX caching? */
void
show_isupport(struct Client *client_p)
{
    rb_dlink_node *ptr;
    struct isupportitem *item;
    const char *value;
    char buf[512];
    int extra_space;
    unsigned int nchars, nparams;
    int l;

    extra_space = strlen(client_p->name);
    /* UID */
    if (!MyClient(client_p) && extra_space < 9)
        extra_space = 9;
    /* :<me.name> 005 <nick> <params> :are supported by this server */
    /* form_str(RPL_ISUPPORT) is %s :are supported by this server */
    extra_space += strlen(me.name) + 1 + strlen(form_str(RPL_ISUPPORT));

    nchars = extra_space, nparams = 0, buf[0] = '\0';
    RB_DLINK_FOREACH(ptr, isupportlist.head) {
        item = ptr->data;
        value = (*item->func)(item->param);
        if (value == NULL)
            continue;
        l = strlen(item->name) + (EmptyString(value) ? 0 : 1 + strlen(value));
        if (nchars + l + (nparams > 0) >= sizeof buf || nparams + 1 > 12) {
            sendto_one_numeric(client_p, RPL_ISUPPORT, form_str(RPL_ISUPPORT), buf);
            nchars = extra_space, nparams = 0, buf[0] = '\0';
        }
        if (nparams > 0)
            rb_strlcat(buf, " ", sizeof buf), nchars++;
        rb_strlcat(buf, item->name, sizeof buf);
        if (!EmptyString(value)) {
            rb_strlcat(buf, "=", sizeof buf);
            rb_strlcat(buf, value, sizeof buf);
        }
        nchars += l;
        nparams++;
    }
    if (nparams > 0)
        sendto_one_numeric(client_p, RPL_ISUPPORT, form_str(RPL_ISUPPORT), buf);
}

const char *
isupport_intptr(const void *ptr)
{
    static char buf[15];
    rb_snprintf(buf, sizeof buf, "%d", *(const int *)ptr);
    return buf;
}

const char *
isupport_boolean(const void *ptr)
{

    return *(const int *)ptr ? "" : NULL;
}

const char *
isupport_string(const void *ptr)
{

    return (const char *)ptr;
}

const char *
isupport_stringptr(const void *ptr)
{
    return *(char * const *)ptr;
}

static const char *
isupport_chanmodes(const void *ptr)
{
    static char result[80];

    rb_snprintf(result, sizeof result, "%s%sb%s,k,%sl%s,%s",
                ConfigChannel.use_except ? "e" : "",
                ConfigChannel.use_invex ? "I" : "",
                strchr(ConfigChannel.disabledmodes, 'y') ? "" : "y",
                ConfigChannel.use_forward ? "f" : "",
                strchr(ConfigChannel.disabledmodes, 'j') ? "" : "j",
                cflagsbuf);
    return result;
}

static const char *
isupport_chantypes(const void *ptr)
{
    return ConfigChannel.use_local_channels ? "&#" : "#";
}

static const char *
isupport_chanlimit(const void *ptr)
{
    static char result[30];

    rb_snprintf(result, sizeof result, "%s:%i",
                ConfigChannel.use_local_channels ? "&#" : "#",
                ConfigChannel.max_chans_per_user);
    return result;
}

static const char*
isupport_prefix(const void *ptr)
{
    static char result[13];

    rb_snprintf(result, sizeof result, "(%s%so%sv)%s%s@%s+",
                ConfigChannel.use_owner ? "q" : "",
                ConfigChannel.use_admin ? "a" : "",
                ConfigChannel.use_halfop ? "h" : "",
                ConfigChannel.use_owner ? "~" : "",
                ConfigChannel.use_admin ? "&" : "",
                ConfigChannel.use_halfop ? "%" : "");
    return result;
}

static const char *
isupport_maxlist(const void *ptr)
{
    static char result[30];

    rb_snprintf(result, sizeof result, "bq%s%s:%i",
                ConfigChannel.use_except ? "e" : "",
                ConfigChannel.use_invex ? "I" : "",
                ConfigChannel.max_bans);
    return result;
}

static const char *
isupport_targmax(const void *ptr)
{
    static char result[200];

    rb_snprintf(result, sizeof result, "NAMES:1,LIST:1,KICK:1,WHOIS:1,PRIVMSG:%d,NOTICE:%d,ACCEPT:,MONITOR:",
                ConfigFileEntry.max_targets,
                ConfigFileEntry.max_targets);
    return result;
}

static const char *
isupport_extban(const void *ptr)
{
    const char *p;
    static char result[200];

    p = get_extban_string();
    if (EmptyString(p))
        return NULL;
    rb_snprintf(result, sizeof result, "$,%s", p);
    return result;
}

static const char *
isupport_ownermode(const void *ptr)
{
    static char result[200];

    if(!ConfigChannel.use_owner)
        return NULL;

    rb_snprintf(result, sizeof result, "q");

    return result;
}

void
init_isupport(void)
{
    static int maxmodes = MAXMODEPARAMS;
    static int nicklen = NICKLEN-1;
    static int channellen = LOC_CHANNELLEN;
    static int topiclen = TOPICLEN;

    add_isupport("CHANTYPES", isupport_chantypes, NULL);
    add_isupport("EXCEPTS", isupport_boolean, &ConfigChannel.use_except);
    add_isupport("INVEX", isupport_boolean, &ConfigChannel.use_invex);
    add_isupport("CHANMODES", isupport_chanmodes, NULL);
    add_isupport("CHANLIMIT", isupport_chanlimit, NULL);
    add_isupport("PREFIX", isupport_prefix, NULL);
    add_isupport("OWNER", isupport_ownermode, NULL);
    add_isupport("MAXLIST", isupport_maxlist, NULL);
    add_isupport("MODES", isupport_intptr, &maxmodes);
    add_isupport("NETWORK", isupport_stringptr, &ServerInfo.network_name);
    add_isupport("KNOCK", isupport_boolean, &ConfigChannel.use_knock);
    add_isupport("STATUSMSG", isupport_string, "@+");
    add_isupport("CALLERID", isupport_string, "g");
    add_isupport("CASEMAPPING", isupport_string, "rfc1459");
    add_isupport("NICKLEN", isupport_intptr, &nicklen);
    add_isupport("CHANNELLEN", isupport_intptr, &channellen);
    add_isupport("TOPICLEN", isupport_intptr, &topiclen);
    add_isupport("ETRACE", isupport_string, "");
    add_isupport("CPRIVMSG", isupport_string, "");
    add_isupport("CNOTICE", isupport_string, "");
    add_isupport("DEAF", isupport_string, "D");
    add_isupport("MONITOR", isupport_intptr, &ConfigFileEntry.max_monitor);
    add_isupport("FNC", isupport_string, "");
    add_isupport("TARGMAX", isupport_targmax, NULL);
    add_isupport("EXTBAN", isupport_extban, NULL);
    add_isupport("WHOX", isupport_string, "");
    add_isupport("CLIENTVER", isupport_string, "3.0");
}