/* modules/m_cap.c
 *
 *  Copyright (C) 2005 Lee Hardy <lee@leeh.co.uk>
 *  Copyright (C) 2005 ircd-ratbox development team
 *
 * 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.
 *
 */

#include "stdinc.h"
#include "class.h"
#include "client.h"
#include "match.h"
#include "ircd.h"
#include "numeric.h"
#include "msg.h"
#include "parse.h"
#include "modules.h"
#include "s_serv.h"
#include "s_user.h"

typedef int (*bqcmp)(const void *, const void *);

static int m_cap(struct Client *, struct Client *, int, const char **);
static int modinit(void);

struct Message cap_msgtab = {
    "CAP", 0, 0, 0, MFLG_SLOW,
    {{m_cap, 2}, {m_cap, 2}, mg_ignore, mg_ignore, mg_ignore, {m_cap, 2}}
};

mapi_clist_av1 cap_clist[] = { &cap_msgtab, NULL };
DECLARE_MODULE_AV1(cap, modinit, NULL, cap_clist, NULL, NULL, "$Revision: 676 $");

#define _CLICAP(name, capserv, capclient, flags)	\
	{ (name), (capserv), (capclient), (flags), sizeof(name) - 1 }

#define CLICAP_FLAGS_STICKY	0x001

static struct clicap {
    const char *name;
    int cap_serv;		/* for altering s->c */
    int cap_cli;		/* for altering c->s */
    int flags;
    int namelen;
} clicap_list[] = {
    _CLICAP("multi-prefix",	CLICAP_MULTI_PREFIX, 0, 0),
    _CLICAP("sasl", CLICAP_SASL, 0, 0),
    _CLICAP("account-notify", CLICAP_ACCOUNT_NOTIFY, 0, 0),
    _CLICAP("extended-join", CLICAP_EXTENDED_JOIN, 0, 0),
//    _CLICAP("away-notify", CLICAP_AWAY_NOTIFY, 0, 0),
};

#define CLICAP_LIST_LEN (sizeof(clicap_list) / sizeof(struct clicap))

static int clicap_sort(struct clicap *, struct clicap *);

static int
modinit(void)
{
    qsort(clicap_list, CLICAP_LIST_LEN, sizeof(struct clicap),
          (bqcmp) clicap_sort);
    return 0;
}

static int
clicap_sort(struct clicap *one, struct clicap *two)
{
    return irccmp(one->name, two->name);
}

static int
clicap_compare(const char *name, struct clicap *cap)
{
    return irccmp(name, cap->name);
}

/* clicap_find()
 *   Used iteratively over a buffer, extracts individual cap tokens.
 *
 * Inputs: buffer to start iterating over (NULL to iterate over existing buf)
 *         int pointer to whether the cap token is negated
 *         int pointer to whether we finish with success
 * Ouputs: Cap entry if found, NULL otherwise.
 */
static struct clicap *
clicap_find(const char *data, int *negate, int *finished)
{
    static char buf[BUFSIZE];
    static char *p;
    struct clicap *cap;
    char *s;

    *negate = 0;

    if(data) {
        rb_strlcpy(buf, data, sizeof(buf));
        p = buf;
    }

    if(*finished)
        return NULL;

    /* skip any whitespace */
    while(*p && IsSpace(*p))
        p++;

    if(EmptyString(p)) {
        *finished = 1;
        return NULL;
    }

    if(*p == '-') {
        *negate = 1;
        p++;

        /* someone sent a '-' without a parameter.. */
        if(*p == '\0')
            return NULL;
    }

    if((s = strchr(p, ' ')))
        *s++ = '\0';

    if((cap = bsearch(p, clicap_list, CLICAP_LIST_LEN,
                      sizeof(struct clicap), (bqcmp) clicap_compare))) {
        if(s)
            p = s;
        else
            *finished = 1;
    }

    return cap;
}

/* clicap_generate()
 *   Generates a list of capabilities.
 *
 * Inputs: client to send to, subcmd to send,
 *         flags to match against: 0 to do none, -1 if client has no flags,
 *         int to whether we are doing CAP CLEAR
 * Outputs: None
 */
static void
clicap_generate(struct Client *source_p, const char *subcmd, int flags, int clear)
{
    char buf[BUFSIZE];
    char capbuf[BUFSIZE];
    char *p;
    int buflen = 0;
    int curlen, mlen;
    size_t i;

    mlen = sprintf(buf, ":%s CAP %s %s",
                      me.name,
                      EmptyString(source_p->name) ? "*" : source_p->name,
                      subcmd);

    p = capbuf;
    buflen = mlen;

    /* shortcut, nothing to do */
    if(flags == -1) {
        sendto_one(source_p, "%s :", buf);
        return;
    }

    for(i = 0; i < CLICAP_LIST_LEN; i++) {
        if(flags) {
            if(!IsCapable(source_p, clicap_list[i].cap_serv))
                continue;
            /* they are capable of this, check sticky */
            else if(clear && clicap_list[i].flags & CLICAP_FLAGS_STICKY)
                continue;
        }

        /* \r\n\0, possible "-~=", space, " *" */
        if(buflen + clicap_list[i].namelen >= BUFSIZE - 10) {
            /* remove our trailing space -- if buflen == mlen
             * here, we didnt even succeed in adding one.
             */
            if(buflen != mlen)
                *(p - 1) = '\0';
            else
                *p = '\0';

            sendto_one(source_p, "%s * :%s", buf, capbuf);
            p = capbuf;
            buflen = mlen;
        }

        if(clear) {
            *p++ = '-';
            buflen++;

            /* needs a client ack */
            if(clicap_list[i].cap_cli &&
               IsCapable(source_p, clicap_list[i].cap_cli)) {
                *p++ = '~';
                buflen++;
            }
        } else {
            if(clicap_list[i].flags & CLICAP_FLAGS_STICKY) {
                *p++ = '=';
                buflen++;
            }

            /* if we're doing an LS, then we only send this if
             * they havent ack'd
             */
            if(clicap_list[i].cap_cli &&
               (!flags || !IsCapable(source_p, clicap_list[i].cap_cli))) {
                *p++ = '~';
                buflen++;
            }
        }

        curlen = sprintf(p, "%s ", clicap_list[i].name);
        p += curlen;
        buflen += curlen;
    }

    /* remove trailing space */
    if(buflen != mlen)
        *(p - 1) = '\0';
    else
        *p = '\0';

    sendto_one(source_p, "%s :%s", buf, capbuf);
}

static void
cap_ack(struct Client *source_p, const char *arg)
{
    struct clicap *cap;
    int capadd = 0, capdel = 0;
    int finished = 0, negate;

    if(EmptyString(arg))
        return;

    for(cap = clicap_find(arg, &negate, &finished); cap;
        cap = clicap_find(NULL, &negate, &finished)) {
        /* sent an ACK for something they havent REQd */
        if(!IsCapable(source_p, cap->cap_serv))
            continue;

        if(negate) {
            /* dont let them ack something sticky off */
            if(cap->flags & CLICAP_FLAGS_STICKY)
                continue;

            capdel |= cap->cap_cli;
        } else
            capadd |= cap->cap_cli;
    }

    source_p->localClient->caps |= capadd;
    source_p->localClient->caps &= ~capdel;
}

static void
cap_clear(struct Client *source_p, const char *arg)
{
    clicap_generate(source_p, "ACK",
                    source_p->localClient->caps ? source_p->localClient->caps : -1, 1);

    /* XXX - sticky capabs */
#ifdef CLICAP_STICKY
    source_p->localClient->caps = source_p->localClient->caps & CLICAP_STICKY;
#else
    source_p->localClient->caps = 0;
#endif
}

static void
cap_end(struct Client *source_p, const char *arg)
{
    if(IsRegistered(source_p))
        return;

    source_p->flags &= ~FLAGS_CLICAP;

    if(source_p->name[0] && source_p->flags & FLAGS_SENTUSER) {
        char buf[USERLEN+1];
        rb_strlcpy(buf, source_p->username, sizeof(buf));
        register_local_user(source_p, source_p, buf);
    }
}

static void
cap_list(struct Client *source_p, const char *arg)
{
    /* list of what theyre currently using */
    clicap_generate(source_p, "LIST",
                    source_p->localClient->caps ? source_p->localClient->caps : -1, 0);
}

static void
cap_ls(struct Client *source_p, const char *arg)
{
    if(!IsRegistered(source_p))
        source_p->flags |= FLAGS_CLICAP;

    /* list of what we support */
    clicap_generate(source_p, "LS", 0, 0);
}

static void
cap_req(struct Client *source_p, const char *arg)
{
    char buf[BUFSIZE];
    char pbuf[2][BUFSIZE];
    struct clicap *cap;
    int buflen, plen;
    int i = 0;
    int capadd = 0, capdel = 0;
    int finished = 0, negate;

    if(!IsRegistered(source_p))
        source_p->flags |= FLAGS_CLICAP;

    if(EmptyString(arg))
        return;

    buflen = snprintf(buf, sizeof(buf), ":%s CAP %s ACK",
                         me.name, EmptyString(source_p->name) ? "*" : source_p->name);

    pbuf[0][0] = '\0';
    plen = 0;

    for(cap = clicap_find(arg, &negate, &finished); cap;
        cap = clicap_find(NULL, &negate, &finished)) {
        /* filled the first array, but cant send it in case the
         * request fails.  one REQ should never fill more than two
         * buffers --fl
         */
        if(buflen + plen + cap->namelen + 6 >= BUFSIZE) {
            pbuf[1][0] = '\0';
            plen = 0;
            i = 1;
        }

        if(negate) {
            if(cap->flags & CLICAP_FLAGS_STICKY) {
                finished = 0;
                break;
            }

            strcat(pbuf[i], "-");
            plen++;

            capdel |= cap->cap_serv;
        } else {
            if(cap->flags & CLICAP_FLAGS_STICKY) {
                strcat(pbuf[i], "=");
                plen++;
            }

            capadd |= cap->cap_serv;
        }

        if(cap->cap_cli) {
            strcat(pbuf[i], "~");
            plen++;
        }

        strcat(pbuf[i], cap->name);
        strcat(pbuf[i], " ");
        plen += (cap->namelen + 1);
    }

    if(!finished) {
        sendto_one(source_p, ":%s CAP %s NAK :%s",
                   me.name, EmptyString(source_p->name) ? "*" : source_p->name, arg);
        return;
    }

    if(i) {
        sendto_one(source_p, "%s * :%s", buf, pbuf[0]);
        sendto_one(source_p, "%s :%s", buf, pbuf[1]);
    } else
        sendto_one(source_p, "%s :%s", buf, pbuf[0]);

    source_p->localClient->caps |= capadd;
    source_p->localClient->caps &= ~capdel;
}

static struct clicap_cmd {
    const char *cmd;
    void (*func)(struct Client *source_p, const char *arg);
} clicap_cmdlist[] = {
    /* This list *MUST* be in alphabetical order */
    { "ACK",	cap_ack		},
    { "CLEAR",	cap_clear	},
    { "END",	cap_end		},
    { "LIST",	cap_list	},
    { "LS",		cap_ls		},
    { "REQ",	cap_req		},
};

static int
clicap_cmd_search(const char *command, struct clicap_cmd *entry)
{
    return irccmp(command, entry->cmd);
}

static int
m_cap(struct Client *client_p, struct Client *source_p, int parc, const char *parv[])
{
    struct clicap_cmd *cmd;

    if(!(cmd = bsearch(parv[1], clicap_cmdlist,
                       sizeof(clicap_cmdlist) / sizeof(struct clicap_cmd),
                       sizeof(struct clicap_cmd), (bqcmp) clicap_cmd_search))) {
        sendto_one(source_p, form_str(ERR_INVALIDCAPCMD),
                   me.name, EmptyString(source_p->name) ? "*" : source_p->name,
                   parv[1]);
        return 0;
    }

    (cmd->func)(source_p, parv[2]);
    return 0;
}