Generate a YGOPro Lua script for the following Yu-Gi-Oh card effect:
There can only be 1 "Earthbound Immortal" monster on the field. If there is no face-up Field Spell on the field, destroy this card. Your opponent's monsters cannot target this card for attacks. This card can attack directly. If this card destroys an opponent's monster by battle: Inflict damage to your opponent equal to the destroyed monster's original ATK.
--地縛神 Ccapac Apu
--Earthbound Immortal Ccapac Apu
local s,id=GetID()
function s.initial_effect(c)
	--There can only be 1 "Earthbound Immortal" on the field
	c:SetUniqueOnField(1,1,aux.FilterBoolFunction(Card.IsSetCard,SET_EARTHBOUND_IMMORTAL),LOCATION_MZONE)
	--Destroy it if no face-up Field Spell is on the field
	local e1=Effect.CreateEffect(c)
	e1:SetType(EFFECT_TYPE_SINGLE)
	e1:SetProperty(EFFECT_FLAG_SINGLE_RANGE)
	e1:SetRange(LOCATION_MZONE)
	e1:SetCode(EFFECT_SELF_DESTROY)
	e1:SetCondition(s.sdcon)
	c:RegisterEffect(e1)
	--Cannot be targeted for attacks
	local e2=Effect.CreateEffect(c)
	e2:SetType(EFFECT_TYPE_SINGLE)
	e2:SetCode(EFFECT_CANNOT_BE_BATTLE_TARGET)
	e2:SetProperty(EFFECT_FLAG_SINGLE_RANGE)
	e2:SetRange(LOCATION_MZONE)
	e2:SetValue(aux.imval2)
	c:RegisterEffect(e2)
	--Can attack directly
	local e3=Effect.CreateEffect(c)
	e3:SetType(EFFECT_TYPE_SINGLE)
	e3:SetCode(EFFECT_DIRECT_ATTACK)
	c:RegisterEffect(e3)
	--Inflict damage to the opponent
	local e4=Effect.CreateEffect(c)
	e4:SetDescription(aux.Stringid(id,0))
	e4:SetCategory(CATEGORY_DAMAGE)
	e4:SetType(EFFECT_TYPE_SINGLE+EFFECT_TYPE_TRIGGER_F)
	e4:SetCode(EVENT_BATTLE_DESTROYING)
	e4:SetTarget(s.damtg)
	e4:SetOperation(s.damop)
	c:RegisterEffect(e4)
end
s.listed_series={SET_EARTHBOUND_IMMORTAL}
function s.sdcon(e)
	local c=e:GetHandler()
	if c:IsStatus(STATUS_BATTLE_DESTROYED) then return false end
	return not Duel.IsExistingMatchingCard(Card.IsFaceup,0,LOCATION_FZONE,LOCATION_FZONE,1,nil)
end
function s.damtg(e,tp,eg,ep,ev,re,r,rp,chk)
	if chk==0 then return true end
	local tc=e:GetHandler():GetBattleTarget()
	local atk=tc:GetBaseAttack()
	if atk<0 then atk=0 end
	Duel.SetTargetPlayer(1-tp)
	Duel.SetTargetParam(atk)
	Duel.SetOperationInfo(0,CATEGORY_DAMAGE,nil,0,1-tp,atk)
end
function s.damop(e,tp,eg,ep,ev,re,r,rp)
	local p,d=Duel.GetChainInfo(0,CHAININFO_TARGET_PLAYER,CHAININFO_TARGET_PARAM)
	Duel.Damage(p,d,REASON_EFFECT)
end