TFS 0.X total player invisible

[eyez]

A spell to players be invisible to others players is so fun...
I tried to make it for a custom project, there are a lot of requests about it here on forum so i put some scripts together i make it to work:

<instant name="Shadow Walker" words="utana vis" lvl="8" manapercent="70" exhaustion="2000" needlearn="0" event="script" value="shadow.lua">
        <vocation id="1"/>
    </instant>

function onCastSpell(cid, var)
    parameters = {cid=cid}
    setPlayerGroupId(cid, 2)
    doCreatureExecuteTalkAction(cid, "/ghost", TRUE)
    addEvent(talk, 300000, parameters)
    return true
end

function talk(parameters)
    doCreatureExecuteTalkAction(parameters.cid, "/ghost", TRUE)
    setPlayerGroupId(parameters.cid, 1)
end

<event type="login" name="cancelInv" event="script" value="cancelinv.lua"/>

registerCreatureEvent(cid, "cancelInv")

if(getPlayerGroupId(cid) == 2) then
    setPlayerGroupId(cid, 1)
end
if(isPlayerGhost(cid)) then
    doCreatureExecuteTalkAction(cid, "/ghost", TRUE)
end

but there are a few things that i need to change and i don't know why
and i cant use as i make cause it is totally unplayable, much overpower


1) it's not reciving area damage, like gfbs UEs, it should give damage and cancel inv
2) players who are not invisible can enter on the same SQM of this inv player
3) monsters who can see utana vid should cancel players inv by attacking


is anyone know how to make this 3 changes?
if it is relevant, my source code is: Fir3element/3777 (https://github.com/Fir3element/3777/tree/master/src)