Generate a YGOPro Lua script for the following Yu-Gi-Oh card effect:
When your opponent Summons a monster(s): Change that monster(s) to face-down Defense Position. Monsters changed to face-down Defense Position by this effect cannot change their battle positions.
--底なし落とし穴
--Floodgate Trap Hole
local s,id=GetID()
function s.initial_effect(c)
	--When opponent summons a monster(s), change it to face-down defense position
	local e1=Effect.CreateEffect(c)
	e1:SetCategory(CATEGORY_POSITION)
	e1:SetType(EFFECT_TYPE_ACTIVATE)
	e1:SetCode(EVENT_SUMMON_SUCCESS)
	e1:SetTarget(s.target)
	e1:SetOperation(s.activate)
	c:RegisterEffect(e1)
	local e2=e1:Clone()
	e2:SetCode(EVENT_SPSUMMON_SUCCESS)
	c:RegisterEffect(e2)
	local e3=e1:Clone()
	e3:SetCode(EVENT_FLIP_SUMMON_SUCCESS)
	e3:SetTarget(s.target2)
	c:RegisterEffect(e3)
end
function s.filter(c,tp)
	return c:IsFaceup() and not c:IsSummonPlayer(tp) and c:IsCanTurnSet()
end
function s.target(e,tp,eg,ep,ev,re,r,rp,chk)
	if chk==0 then return eg and eg:IsExists(s.filter,1,nil,tp) end
	local g=eg:Filter(s.filter,nil,tp)
	Duel.SetTargetCard(g)
end
function s.target2(e,tp,eg,ep,ev,re,r,rp,chk)
	local tc=eg:GetFirst()
	if chk==0 then return rp==1-tp and tc:IsFaceup() and tc:IsCanTurnSet() end
	Duel.SetTargetCard(tc)
end
function s.activate(e,tp,eg,ep,ev,re,r,rp)
	local g=Duel.GetTargetCards(e)
	if Duel.ChangePosition(g,POS_FACEDOWN_DEFENSE)~=0 then
		local og=Duel.GetOperatedGroup()
		local tc=og:GetFirst()
		for tc in aux.Next(og) do
			--Cannot change its battle position
			local e1=Effect.CreateEffect(e:GetHandler())
			e1:SetDescription(3313)
			e1:SetProperty(EFFECT_FLAG_CLIENT_HINT)
			e1:SetType(EFFECT_TYPE_SINGLE)
			e1:SetCode(EFFECT_CANNOT_CHANGE_POSITION)
			e1:SetReset(RESET_EVENT|RESETS_STANDARD)
			tc:RegisterEffect(e1)
		end
	end
end