Lua check item pos/stackpos? TFS 1.3x

[Lava Titan]

Hello, I'm trying to disable the player from using an item unless he has it on the inventory, the first method that comes to my mind is checking for item position but I can't find out how to do that in multiple ways like, checking if item is in depot, check if item is in ground, check if item is in monster body, check if item is in some random container on the ground...

 

[Evil Puncker]

look firework script for example:

function onUse(player, item, fromPosition, target, toPosition, isHotkey)
    if fromPosition.x ~= CONTAINER_POSITION then
        fromPosition:sendMagicEffect(math.random(CONST_ME_FIREWORK_YELLOW, CONST_ME_FIREWORK_BLUE))
    else
        local position = player:getPosition()
        position:sendMagicEffect(CONST_ME_HITBYFIRE)
        position:sendMagicEffect(CONST_ME_EXPLOSIONAREA)
        player:say("Ouch! Rather place it on the ground next time.", TALKTYPE_MONSTER_SAY)
        player:addHealth(-10)
        player:addAchievementProgress("Rocket in Pocket", 3)
    end
    player:addAchievementProgress("Fireworks in the Sky", 250)
    item:remove()
    return true
end