Generate a YGOPro Lua script for the following Yu-Gi-Oh card effect:
When an opponent's monster declares an attack: You can Special Summon this card from your hand, and if you do, change the attack target to this card and proceed to damage calculation. This card cannot be destroyed by that battle.
--工作列車シグナル・レッド
--Construction Train Signal Red
local s,id=GetID()
function s.initial_effect(c)
	--spsummon
	local e1=Effect.CreateEffect(c)
	e1:SetDescription(aux.Stringid(id,0))
	e1:SetCategory(CATEGORY_SPECIAL_SUMMON)
	e1:SetType(EFFECT_TYPE_FIELD+EFFECT_TYPE_TRIGGER_O)
	e1:SetCode(EVENT_ATTACK_ANNOUNCE)
	e1:SetRange(LOCATION_HAND)
	e1:SetCondition(s.condition)
	e1:SetTarget(s.target)
	e1:SetOperation(s.operation)
	c:RegisterEffect(e1)
end
function s.condition(e,tp,eg,ep,ev,re,r,rp)
	return Duel.GetAttacker():GetControler()~=tp
end
function s.target(e,tp,eg,ep,ev,re,r,rp,chk)
	local c=e:GetHandler()
	if chk==0 then return Duel.GetLocationCount(tp,LOCATION_MZONE)>0
		and c:IsCanBeSpecialSummoned(e,0,tp,false,false) end
	Duel.SetOperationInfo(0,CATEGORY_SPECIAL_SUMMON,c,1,0,0)
end
function s.operation(e,tp,eg,ep,ev,re,r,rp)
	local c=e:GetHandler()
	if c:IsRelateToEffect(e) and Duel.SpecialSummon(c,0,tp,tp,false,false,POS_FACEUP)~=0 then
		local a=Duel.GetAttacker()
		if a:CanAttack() and not a:IsImmuneToEffect(e) then
			local e1=Effect.CreateEffect(c)
			e1:SetType(EFFECT_TYPE_SINGLE)
			e1:SetCode(EFFECT_INDESTRUCTABLE_BATTLE)
			e1:SetProperty(EFFECT_FLAG_CANNOT_DISABLE)
			e1:SetValue(1)
			e1:SetReset(RESET_PHASE|PHASE_DAMAGE)
			c:RegisterEffect(e1)
			Duel.CalculateDamage(a,c)
		end
	end
end