/*
 * jid.c
 * vim: expandtab:ts=4:sts=4:sw=4
 *
 * Copyright (C) 2012 - 2019 James Booth <boothj5@gmail.com>
 *
 * This file is part of Profanity.
 *
 * Profanity 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 3 of the License, or
 * (at your option) any later version.
 *
 * Profanity 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 Profanity.  If not, see <https://www.gnu.org/licenses/>.
 *
 * In addition, as a special exception, the copyright holders give permission to
 * link the code of portions of this program with the OpenSSL library under
 * certain conditions as described in each individual source file, and
 * distribute linked combinations including the two.
 *
 * You must obey the GNU General Public License in all respects for all of the
 * code used other than OpenSSL. If you modify file(s) with this exception, you
 * may extend this exception to your version of the file(s), but you are not
 * obligated to do so. If you do not wish to do so, delete this exception
 * statement from your version. If you delete this exception statement from all
 * source files in the program, then also delete it here.
 *
 */

#include "config.h"

#include <stdlib.h>
#include <string.h>

#include <glib.h>

#include "common.h"
#include "xmpp/jid.h"

#define JID_MAX_PART_LEN  1023
#define JID_MAX_TOTAL_LEN 3071

static gboolean
_is_invalid_local_char(gunichar c)
{
    // RFC 6122: " & ' / : < > @
    // Also space is forbidden.
    return (c == ' ' || c == '"' || c == '&' || c == '\'' || c == '/' || c == ':' || c == '<' || c == '>' || c == '@');
}

Jid*
jid_create(const gchar* const str)
{
    if (str == NULL) {
        return NULL;
    }

    gchar* trimmed = g_strdup(str);
    if (trimmed == NULL) {
        return NULL;
    }

    size_t len = strlen(trimmed);
    if (len == 0 || len > JID_MAX_TOTAL_LEN) {
        g_free(trimmed);
        return NULL;
    }

    if (!g_utf8_validate(trimmed, -1, NULL)) {
        g_free(trimmed);
        return NULL;
    }

    Jid* result = g_new0(Jid, 1);
    result->refcnt = 1;
    result->str = trimmed;

    gchar* slashp = g_utf8_strchr(trimmed, -1, '/');
    auto_gchar gchar* bare = NULL;

    if (slashp) {
        result->resourcepart = g_strdup(slashp + 1);
        bare = g_utf8_substring(trimmed, 0, g_utf8_pointer_to_offset(trimmed, slashp));
        result->fulljid = g_strdup(trimmed);
    } else {
        bare = g_strdup(trimmed);
    }

    // Validate resourcepart
    if (result->resourcepart) {
        size_t rlen = strlen(result->resourcepart);
        if (rlen == 0 || rlen > JID_MAX_PART_LEN) {
            jid_destroy(result);
            return NULL;
        }
    }

    gchar* atp = g_utf8_strchr(bare, -1, '@');
    gchar* domain_start = bare;

    if (atp) {
        result->localpart = g_utf8_substring(bare, 0, g_utf8_pointer_to_offset(bare, atp));
        domain_start = atp + 1;

        // Validate localpart
        size_t llen = strlen(result->localpart);
        if (llen == 0 || llen > JID_MAX_PART_LEN) {
            jid_destroy(result);
            return NULL;
        }

        const gchar* p = result->localpart;
        while (*p) {
            gunichar c = g_utf8_get_char(p);
            if (_is_invalid_local_char(c)) {
                jid_destroy(result);
                return NULL;
            }
            p = g_utf8_next_char(p);
        }
    }

    result->domainpart = g_strdup(domain_start);
    result->barejid = g_utf8_strdown(bare, -1);

    // Validate domainpart
    size_t dlen = result->domainpart ? strlen(result->domainpart) : 0;
    if (dlen == 0 || dlen > JID_MAX_PART_LEN) {
        jid_destroy(result);
        return NULL;
    }

    // Domainpart cannot contain @
    if (g_utf8_strchr(result->domainpart, -1, '@')) {
        jid_destroy(result);
        return NULL;
    }

    return result;
}

gboolean
jid_is_valid(const gchar* const str)
{
    auto_jid Jid* jid = jid_create(str);
    return (jid != NULL);
}

gboolean
jid_is_valid_user_jid(const gchar* const str)
{
    auto_jid Jid* jid = jid_create(str);
    return (jid != NULL && jid->localpart != NULL);
}

Jid*
jid_create_from_bare_and_resource(const gchar* const barejid, const gchar* const resource)
{
    auto_gchar gchar* jid = create_fulljid(barejid, resource);
    return jid_create(jid);
}

void
jid_auto_destroy(Jid** jid)
{
    if (jid == NULL)
        return;
    jid_destroy(*jid);
}

void
jid_ref(Jid* jid)
{
    jid->refcnt++;
}

void
jid_destroy(Jid* jid)
{
    if (jid == NULL) {
        return;
    }
    if (jid->refcnt > 1) {
        jid->refcnt--;
        return;
    }

    g_free(jid->str);
    g_free(jid->localpart);
    g_free(jid->domainpart);
    g_free(jid->resourcepart);
    g_free(jid->barejid);
    g_free(jid->fulljid);
    free(jid);
}

gboolean
jid_is_valid_room_form(Jid* jid)
{
    return (jid->fulljid != NULL);
}

/*
 * Given a barejid, and resourcepart, create and return a full JID of the form
 * barejid/resourcepart
 * Will return a newly created string that must be freed by the caller
 */
gchar*
create_fulljid(const gchar* const barejid, const gchar* const resource)
{
    auto_gchar gchar* barejidlower = g_utf8_strdown(barejid, -1);
    return g_strdup_printf("%s/%s", barejidlower, resource);
}

/*
 * Get the nickname part of the full JID, e.g.
 * Full JID = "test@conference.server/person"
 * returns "person"
 */
gchar*
get_nick_from_full_jid(const gchar* const full_room_jid)
{
    auto_gcharv gchar** tokens = g_strsplit(full_room_jid, "/", 0);
    gchar* nick_part = NULL;

    if (tokens) {
        if (tokens[0] && tokens[1]) {
            nick_part = strdup(tokens[1]);
        }
    }

    return nick_part;
}

/*
 * get the fulljid, fall back to the barejid
 */
const gchar*
jid_fulljid_or_barejid(Jid* jid)
{
    if (jid->fulljid) {
        return jid->fulljid;
    } else {
        return jid->barejid;
    }
}

gchar*
jid_random_resource(void)
{
    auto_gchar gchar* rand = get_random_string(4);

    gchar* result = g_strdup_printf("profanity.%s", rand);

    return result;
}