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 you take Battle Damage from a battle involving this card, all face-up "Karakuri" monsters you control gain 800 ATK and DEF until the End Phase. While this card is in face-up Attack Position, it cannot be destroyed by battle.
--カラクリ守衛 参壱参
--Karakuri Watchdog mdl 313 "Saizan"
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)
	--atkup
	local e4=Effect.CreateEffect(c)
	e4:SetDescription(aux.Stringid(id,1))
	e4:SetType(EFFECT_TYPE_TRIGGER_F+EFFECT_TYPE_FIELD)
	e4:SetRange(LOCATION_MZONE)
	e4:SetCategory(CATEGORY_ATKCHANGE+CATEGORY_DEFCHANGE)
	e4:SetCode(EVENT_BATTLE_DAMAGE)
	e4:SetCondition(s.atkcon)
	e4:SetOperation(s.atkop)
	c:RegisterEffect(e4)
	--indes
	local e5=Effect.CreateEffect(c)
	e5:SetType(EFFECT_TYPE_SINGLE)
	e5:SetCode(EFFECT_INDESTRUCTABLE_BATTLE)
	e5:SetCondition(s.indcon)
	e5:SetValue(1)
	c:RegisterEffect(e5)
end
s.listed_series={SET_KARAKURI}
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.atkcon(e,tp,eg,ep,ev,re,r,rp)
	return ep==tp and (e:GetHandler()==Duel.GetAttacker() or e:GetHandler()==Duel.GetAttackTarget())
end
function s.filter(c)
	return c:IsFaceup() and c:IsSetCard(SET_KARAKURI)
end
function s.atkop(e,tp,eg,ep,ev,re,r,rp)
	local c=e:GetHandler()
	local g=Duel.GetMatchingGroup(s.filter,tp,LOCATION_MZONE,0,nil)
	local tc=g:GetFirst()
	for tc in aux.Next(g) do
		local e1=Effect.CreateEffect(c)
		e1:SetType(EFFECT_TYPE_SINGLE)
		e1:SetProperty(EFFECT_FLAG_CANNOT_DISABLE)
		e1:SetCode(EFFECT_UPDATE_ATTACK)
		e1:SetReset(RESETS_STANDARD_PHASE_END)
		e1:SetValue(800)
		tc:RegisterEffect(e1)
		local e2=e1:Clone()
		e2:SetCode(EFFECT_UPDATE_DEFENSE)
		tc:RegisterEffect(e2)
	end
end
function s.indcon(e)
	return e:GetHandler():IsPosition(POS_FACEUP_ATTACK)
end