Generate a YGOPro Lua script for the following Yu-Gi-Oh card effect:
When an opponent's monster declares an attack while they control 2 or more face-up monsters and you control a monster: Target 1 face-up monster your opponent controls, except the attacking monster; take control of that face-up monster (until the end of the Battle Phase), and if you do, change the attack target to it and perform damage calculation.
--マジックアーム・シールド
--Magical Arm Shield
local s,id=GetID()
function s.initial_effect(c)
	--Activate
	local e1=Effect.CreateEffect(c)
	e1:SetCategory(CATEGORY_CONTROL)
	e1:SetProperty(EFFECT_FLAG_CARD_TARGET)
	e1:SetType(EFFECT_TYPE_ACTIVATE)
	e1:SetCode(EVENT_ATTACK_ANNOUNCE)
	e1:SetCondition(s.condition)
	e1:SetTarget(s.target)
	e1:SetOperation(s.activate)
	c:RegisterEffect(e1)
end
function s.condition(e,tp,eg,ep,ev,re,r,rp)
	return Duel.IsTurnPlayer(1-tp) and Duel.GetFieldGroupCount(tp,LOCATION_MZONE,0)>0
end
function s.filter(c)
	return c:IsFaceup() and c:IsControlerCanBeChanged()
end
function s.target(e,tp,eg,ep,ev,re,r,rp,chk,chkc)
	local atr=Duel.GetAttacker()
	if chkc then return chkc:IsLocation(LOCATION_MZONE) and chkc:IsControler(1-tp) and s.filter(chkc) end
	if chk==0 then return Duel.IsExistingTarget(s.filter,tp,0,LOCATION_MZONE,1,atr) end
	Duel.Hint(HINT_SELECTMSG,tp,HINTMSG_CONTROL)
	local g=Duel.SelectTarget(tp,s.filter,tp,0,LOCATION_MZONE,1,1,atr)
	Duel.SetOperationInfo(0,CATEGORY_CONTROL,g,1,0,0)
end
function s.activate(e,tp,eg,ep,ev,re,r,rp)
	local tc=Duel.GetFirstTarget()
	local a=Duel.GetAttacker()
	if tc:IsRelateToEffect(e) and tc:IsFaceup() and Duel.GetControl(tc,tp,PHASE_BATTLE,1)~=0 then
		if a:CanAttack() and not a:IsImmuneToEffect(e) then
			Duel.CalculateDamage(a,tc)
		end
	end
end