toribio

new clan_colors[] =
{
    0xFF0000AA, 0xFFF000AA, 0x00FF00AA
}; //cada cor aqui, é a cor de um clan
new clan_tag[sizeof clan_colors][14];

//no OnPlayerConnect:
new pname[MAX_PLAYER_NAME];
GetPlayerName(playerid, pname, sizeof pname);
if(pname[0] == '[' && strfind(pname, "]", true) >= 2) //tem que ter [..] no nick
{
    static clans;
    new bool:is;
    if(clans <= sizeof clans_colors)
    {
        new tag[14];
        strmid(tag, pname, strfind(pname, "[", true), strfind(pname, "]", true));
        for(new i = 0; i < sizeof clan_tag; i++)
            if(strfind(clan_tag[i], tag, false) != -1)
            {
                SetPlayerColor(playerid, clan_colors[i]);
                is = true;
                break;
            } else is = false;
        if(!is)
        {
            new id;
            for(id = 0; id < sizeof clan_tag; id++)
                if(!strlen(clan_tag[id])
                    break;
            strmid(clan_tag[id], tag, 0, strlen(tag));
            SetPlayerColor(playerid, clan_colors[id]);
            clans++;
        }
    }
}

//OnPlayerDisconnect:
new pname[MAX_PLAYER_NAME];
GetPlayerName(playerid, pname, sizeof pname);
if(pname[0] == '[' && strfind(pname, "]", true) >= 2)
{
    new tag[14], has;
    strmid(tag, pname, strfind(pname, "[", true), strfind(pname, "]", true));
    for(new i = 0, t[14], n[MAX_PLAYER_NAME]; i < MAX_PLAYERS]; i++)
    {
        GetPlayerName(i, n, sizeof n);
        if(n[0] == '[' && strfind(n, "]", true) >= 2)
        {
            strmid(t, n, strfind(n, "[", true), strfind(n, "]", true));
            if(playerid != i && strfind(tag, t, false) != -1) has++;
        }
    }
    if(has == 0)
        for(new i = 0; i < sizeof clan_tag; i++)
            if(strfind(clan_tag[i], tag, false) != -1)
                clan_tag[i] = "";
}