Generate a YGOPro Lua script for the following Yu-Gi-Oh card effect:
When this card is Normal or Special Summoned: You can change its battle position. This card can attack while in face-up Defense Position. If it does, apply its DEF for damage calculation. If you have no Spells/Traps in your GY: You can change this face-up Defense Position card you control to Attack Position, and if you do, add 1 "Superheavy Samurai Soul" monster from your Deck to your hand. You can only use this effect of "Superheavy Samurai Wagon" once per turn.
--超重武者ダイ－8
--Superheavy Samurai Wagon
local s,id=GetID()
function s.initial_effect(c)
	--position
	local e1=Effect.CreateEffect(c)
	e1:SetDescription(aux.Stringid(id,0))
	e1:SetCategory(CATEGORY_POSITION)
	e1:SetType(EFFECT_TYPE_SINGLE+EFFECT_TYPE_TRIGGER_O)
	e1:SetCode(EVENT_SUMMON_SUCCESS)
	e1:SetTarget(s.postg)
	e1:SetOperation(s.posop)
	c:RegisterEffect(e1)
	local e2=e1:Clone()
	e2:SetCode(EVENT_SPSUMMON_SUCCESS)
	c:RegisterEffect(e2)
	--defense attack
	local e3=Effect.CreateEffect(c)
	e3:SetType(EFFECT_TYPE_SINGLE)
	e3:SetCode(EFFECT_DEFENSE_ATTACK)
	e3:SetValue(1)
	c:RegisterEffect(e3)
	--search
	local e4=Effect.CreateEffect(c)
	e4:SetDescription(aux.Stringid(id,1))
	e4:SetCategory(CATEGORY_TOHAND+CATEGORY_SEARCH)
	e4:SetType(EFFECT_TYPE_IGNITION)
	e4:SetRange(LOCATION_MZONE)
	e4:SetCountLimit(1,id)
	e4:SetCondition(s.thcon)
	e4:SetTarget(s.thtg)
	e4:SetOperation(s.thop)
	c:RegisterEffect(e4)
end
s.listed_series={SET_SUPERHEAVY_SAMURAI_SOUL}
function s.postg(e,tp,eg,ep,ev,re,r,rp,chk)
	if chk==0 then return true end
	Duel.SetOperationInfo(0,CATEGORY_POSITION,e:GetHandler(),1,0,0)
end
function s.posop(e,tp,eg,ep,ev,re,r,rp)
	local c=e:GetHandler()
	if c:IsRelateToEffect(e) then
		Duel.ChangePosition(c,POS_FACEUP_DEFENSE,POS_FACEUP_ATTACK,POS_FACEUP_ATTACK,POS_FACEUP_ATTACK)
	end
end
function s.thcon(e,tp,eg,ep,ev,re,r,rp)
	return e:GetHandler():IsPosition(POS_FACEUP_DEFENSE)
		and not Duel.IsExistingMatchingCard(Card.IsSpellTrap,tp,LOCATION_GRAVE,0,1,nil)
end
function s.thfilter(c)
	return c:IsSetCard(SET_SUPERHEAVY_SAMURAI_SOUL) and c:IsAbleToHand()
end
function s.thtg(e,tp,eg,ep,ev,re,r,rp,chk)
	if chk==0 then return Duel.IsExistingMatchingCard(s.thfilter,tp,LOCATION_DECK,0,1,nil) end
	Duel.SetOperationInfo(0,CATEGORY_TOHAND,nil,1,tp,LOCATION_DECK)
end
function s.thop(e,tp,eg,ep,ev,re,r,rp)
	local c=e:GetHandler()
	if not c:IsRelateToEffect(e) or Duel.ChangePosition(c,POS_FACEUP_ATTACK)==0 then return end
	Duel.Hint(HINT_SELECTMSG,tp,HINTMSG_ATOHAND)
	local g=Duel.SelectMatchingCard(tp,s.thfilter,tp,LOCATION_DECK,0,1,1,nil)
	if #g>0 then
		Duel.SendtoHand(g,nil,REASON_EFFECT)
		Duel.ConfirmCards(1-tp,g)
	end
end