Generate a YGOPro Lua script for the following Yu-Gi-Oh card effect:
Tribute 1 face-up monster; Special Summon from your Deck, 1 monster with the same original Type and Attribute that the Tributed monster had on the field, but 1 Level lower than its original Level on the field. You can only activate 1 "Downbeat" per turn. * The above text is unofficial and describes the card's functionality in the OCG.
--ダウンビート
--Downbeat
local s,id=GetID()
function s.initial_effect(c)
	--Activate
	local e1=Effect.CreateEffect(c)
	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)
	e1:SetLabel(0)
	c:RegisterEffect(e1)
end
function s.cost(e,tp,eg,ep,ev,re,r,rp,chk)
	e:SetLabel(100)
	if chk==0 then return true end
end
function s.costfilter(c,e,tp)
	return c:IsFaceup() and c:GetOriginalLevel()>0 and Duel.IsExistingMatchingCard(s.spfilter,tp,LOCATION_DECK,0,1,nil,c,e,tp)
end
function s.spfilter(c,tc,e,tp)
	return c:GetOriginalLevel()==tc:GetOriginalLevel()-1
		and c:GetOriginalRace()==tc:GetOriginalRace()
		and c:GetOriginalAttribute()==tc:GetOriginalAttribute()
		and c:IsCanBeSpecialSummoned(e,0,tp,false,false)
end
function s.target(e,tp,eg,ep,ev,re,r,rp,chk)
	if chk==0 then
		if e:GetLabel()~=100 then return false end
		e:SetLabel(0)
		return e:IsHasType(EFFECT_TYPE_ACTIVATE) and Duel.GetLocationCount(tp,LOCATION_MZONE)>-1
			and Duel.CheckReleaseGroupCost(tp,s.costfilter,1,false,nil,nil,e,tp)
	end
	e:SetLabel(0)
	local g=Duel.SelectReleaseGroupCost(tp,s.costfilter,1,1,false,nil,nil,e,tp)
	Duel.Release(g,REASON_COST)
	Duel.SetTargetCard(g)
	Duel.SetOperationInfo(0,CATEGORY_SPECIAL_SUMMON,nil,1,tp,LOCATION_DECK)
end
function s.activate(e,tp,eg,ep,ev,re,r,rp)
	if Duel.GetLocationCount(tp,LOCATION_MZONE)<=0 then return end
	local c=e:GetHandler()
	local tc=Duel.GetFirstTarget()
	Duel.Hint(HINT_SELECTMSG,tp,HINTMSG_SPSUMMON)
	local g=Duel.SelectMatchingCard(tp,s.spfilter,tp,LOCATION_DECK,0,1,1,nil,tc,e,tp)
	if #g>0 then
		Duel.SpecialSummon(g,0,tp,tp,false,false,POS_FACEUP)
	end
end