Generate a YGOPro Lua script for the following Yu-Gi-Oh card effect:
Send 1 face-up Level 8 Dragon monster you control to the GY; Special Summon 1 Rank 8 Dragon Xyz Monster from your Extra Deck (this is treated as an Xyz Summon). You can only activate 1 "Revelation of Hope" per turn.
--希望の天啓
--Revelation of Hope
--scripted by Naim
local s,id=GetID()
function s.initial_effect(c)
	--Special Summon 1 Rank 8 Dragon Xyz Monster from your Extra Deck.
	local e1=Effect.CreateEffect(c)
	e1:SetDescription(aux.Stringid(id,0))
	e1:SetCategory(CATEGORY_SPECIAL_SUMMON)
	e1:SetType(EFFECT_TYPE_ACTIVATE)
	e1:SetCode(EVENT_FREE_CHAIN)
	e1:SetCountLimit(1,id,EFFECT_COUNT_CODE_OATH)
	e1:SetCost(s.cost)
	e1:SetTarget(s.target)
	e1:SetOperation(s.activate)
	c:RegisterEffect(e1)
end
function s.costfilter(c,e,tp)
	return c:IsLevel(8) and c:IsRace(RACE_DRAGON) and c:IsFaceup() and c:IsAbleToGraveAsCost()
		and Duel.IsExistingMatchingCard(s.spfilter,tp,LOCATION_EXTRA,0,1,nil,e,tp,c)
end
function s.spfilter(c,e,tp,costc)
	local pg=aux.GetMustBeMaterialGroup(tp,Group.CreateGroup(),tp,c,nil,REASON_XYZ)
	return #pg<=0 and c:IsRank(8) and c:IsRace(RACE_DRAGON) and c:IsType(TYPE_XYZ)
		and Duel.GetLocationCountFromEx(tp,tp,costc,c)>0
		and c:IsCanBeSpecialSummoned(e,SUMMON_TYPE_XYZ,tp,false,false)
end
function s.cost(e,tp,eg,ep,ev,re,r,rp,chk)
	e:SetLabel(1)
	if chk==0 then return Duel.IsExistingMatchingCard(s.costfilter,tp,LOCATION_MZONE,0,1,nil,e,tp) end
	Duel.Hint(HINT_SELECTMSG,tp,HINTMSG_TOGRAVE)
	local g=Duel.SelectMatchingCard(tp,s.costfilter,tp,LOCATION_MZONE,0,1,1,nil,e,tp)
	Duel.SendtoGrave(g,REASON_COST)
end
function s.target(e,tp,eg,ep,ev,re,r,rp,chk)
	if chk==0 then
		local cost_chk=e:GetLabel()==1
		e:SetLabel(0)
		return cost_chk or Duel.IsExistingMatchingCard(s.spfilter,tp,LOCATION_EXTRA,0,1,nil,e,tp)
	end
	Duel.SetOperationInfo(0,CATEGORY_SPECIAL_SUMMON,nil,1,tp,LOCATION_EXTRA)
end
function s.activate(e,tp,eg,ep,ev,re,r,rp)
	Duel.Hint(HINT_SELECTMSG,tp,HINTMSG_SPSUMMON)
	local sc=Duel.SelectMatchingCard(tp,s.spfilter,tp,LOCATION_EXTRA,0,1,1,nil,e,tp):GetFirst()
	if sc and Duel.SpecialSummon(sc,SUMMON_TYPE_XYZ,tp,tp,false,false,POS_FACEUP)>0 then
		sc:CompleteProcedure()
	end
end