Generate a YGOPro Lua script for the following Yu-Gi-Oh card effect:
This card must attack if able. When this face-up card is selected as an attack target, change its battle position. When this card destroys an opponent's monster by battle and sends it to the Graveyard, select 1 Level 4 or lower "Karakuri" monster in your Graveyard, and Special Summon it in face-up Defense Position.
--カラクリ忍者 九壱九
--Karakuri Ninja mdl 919 "Kuick"
local s,id=GetID()
function s.initial_effect(c)
	--must attack
	local e1=Effect.CreateEffect(c)
	e1:SetType(EFFECT_TYPE_SINGLE)
	e1:SetCode(EFFECT_MUST_ATTACK)
	c:RegisterEffect(e1)
	--pos change
	local e3=Effect.CreateEffect(c)
	e3:SetDescription(aux.Stringid(id,0))
	e3:SetCategory(CATEGORY_POSITION)
	e3:SetType(EFFECT_TYPE_TRIGGER_F+EFFECT_TYPE_SINGLE)
	e3:SetCode(EVENT_BE_BATTLE_TARGET)
	e3:SetOperation(s.posop)
	c:RegisterEffect(e3)
	--special summon
	local e4=Effect.CreateEffect(c)
	e4:SetDescription(aux.Stringid(id,1))
	e4:SetCategory(CATEGORY_SPECIAL_SUMMON)
	e4:SetType(EFFECT_TYPE_FIELD+EFFECT_TYPE_TRIGGER_F)
	e4:SetProperty(EFFECT_FLAG_CARD_TARGET)
	e4:SetCode(EVENT_BATTLE_DESTROYED)
	e4:SetRange(LOCATION_MZONE)
	e4:SetCondition(s.spcon)
	e4:SetTarget(s.sptg)
	e4:SetOperation(s.spop)
	c:RegisterEffect(e4)
end
function s.posop(e,tp,eg,ep,ev,re,r,rp)
	local c=e:GetHandler()
	if c:IsFaceup() and c:IsRelateToEffect(e) then
		Duel.ChangePosition(c,POS_FACEUP_DEFENSE,0,POS_FACEUP_ATTACK,0)
	end
end
function s.spcon(e,tp,eg,ep,ev,re,r,rp)
	local tc=eg:GetFirst()
	return #eg==1 and tc:GetReasonCard()==e:GetHandler()
		and tc:IsLocation(LOCATION_GRAVE) and tc:IsReason(REASON_BATTLE) 
end
function s.filter(c,e,tp)
	return c:IsLevelBelow(4) and c:IsSetCard(SET_KARAKURI) and c:IsCanBeSpecialSummoned(e,0,tp,false,false,POS_FACEUP_DEFENSE)
end
function s.sptg(e,tp,eg,ep,ev,re,r,rp,chk,chkc)
	if chkc then return chkc:IsLocation(LOCATION_GRAVE) and chkc:IsControler(tp) and s.filter(chkc,e,tp) end
	if chk==0 then return true end
	Duel.Hint(HINT_SELECTMSG,tp,HINTMSG_SPSUMMON)
	local g=Duel.SelectTarget(tp,s.filter,tp,LOCATION_GRAVE,0,1,1,nil,e,tp)
	Duel.SetOperationInfo(0,CATEGORY_SPECIAL_SUMMON,g,1,0,0)
end
function s.spop(e,tp,eg,ep,ev,re,r,rp)
	local tc=Duel.GetFirstTarget()
	if tc and tc:IsRelateToEffect(e) then
		Duel.SpecialSummon(tc,0,tp,tp,false,false,POS_FACEUP_DEFENSE)
	end
end