Generate a YGOPro Lua script for the following Yu-Gi-Oh card effect:
Once per turn, during the End Phase: Change the battle positions of all face-up monsters the turn player controls.
--悪夢の迷宮
--Labyrinth of Nightmare
local s,id=GetID()
function s.initial_effect(c)
	--Activate
	local e1=Effect.CreateEffect(c)
	e1:SetType(EFFECT_TYPE_ACTIVATE)
	e1:SetCode(EVENT_FREE_CHAIN)
	e1:SetHintTiming(0,TIMING_END_PHASE)
	c:RegisterEffect(e1)
	--position
	local e2=Effect.CreateEffect(c)
	e2:SetDescription(aux.Stringid(id,0))
	e2:SetCategory(CATEGORY_POSITION)
	e2:SetType(EFFECT_TYPE_FIELD+EFFECT_TYPE_TRIGGER_F)
	e2:SetRange(LOCATION_SZONE)
	e2:SetCountLimit(1)
	e2:SetCode(EVENT_PHASE+PHASE_END)
	e2:SetTarget(s.postg)
	e2:SetOperation(s.posop)
	c:RegisterEffect(e2)
end
function s.postg(e,tp,eg,ep,ev,re,r,rp,chk)
	if chk==0 then return Duel.IsExistingMatchingCard(Card.IsFaceup,Duel.GetTurnPlayer(),LOCATION_MZONE,0,1,nil) end
	local g=Duel.GetMatchingGroup(Card.IsFaceup,Duel.GetTurnPlayer(),LOCATION_MZONE,0,nil)
	Duel.SetOperationInfo(0,CATEGORY_POSITION,g,#g,0,0)
end
function s.posop(e,tp,eg,ep,ev,re,r,rp)
	local g=Duel.GetMatchingGroup(Card.IsFaceup,Duel.GetTurnPlayer(),LOCATION_MZONE,0,nil)
	Duel.ChangePosition(g,POS_FACEUP_DEFENSE,0,POS_FACEUP_ATTACK,0)
end