Generate a YGOPro Lua script for the following Yu-Gi-Oh card effect:
When you take battle or effect damage: Special Summon 1 DARK Spellcaster-Type monster from your Deck with ATK less than or equal to the damage you took.
--ダーク・ホライズン
--Dark Horizon
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:SetProperty(EFFECT_FLAG_DAMAGE_STEP+EFFECT_FLAG_DAMAGE_CAL)
	e1:SetCode(EVENT_DAMAGE)
	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 ep==tp
end
function s.filter(c,e,tp,dam)
	return c:IsRace(RACE_SPELLCASTER) and c:IsAttribute(ATTRIBUTE_DARK) and c:IsAttackBelow(dam) 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 return Duel.GetLocationCount(tp,LOCATION_MZONE)>0
		and Duel.IsExistingMatchingCard(s.filter,tp,LOCATION_DECK,0,1,nil,e,tp,ev) end
	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
	Duel.Hint(HINT_SELECTMSG,tp,HINTMSG_SPSUMMON)
	local g=Duel.SelectMatchingCard(tp,s.filter,tp,LOCATION_DECK,0,1,1,nil,e,tp,ev)
	if #g>0 then
		Duel.SpecialSummon(g,0,tp,tp,false,false,POS_FACEUP)
	end
end