Generate a YGOPro Lua script for the following Yu-Gi-Oh card effect:
[ Pendulum Effect ] Once per turn, when a monster you control inflicts battle damage to your opponent: You can send the top card of your opponent's Deck to the Graveyard. ---------------------------------------- [ Monster Effect ] This card can attack your opponent directly. If this card attacks, it is changed to Defense Position at the end of the Battle Phase.
--EMブランコブラ
--Performapal Swincobra
local s,id=GetID()
function s.initial_effect(c)
	Pendulum.AddProcedure(c)
	--deckdes
	local e1=Effect.CreateEffect(c)
	e1:SetDescription(aux.Stringid(id,0))
	e1:SetCategory(CATEGORY_DECKDES)
	e1:SetType(EFFECT_TYPE_FIELD+EFFECT_TYPE_TRIGGER_O)
	e1:SetCode(EVENT_BATTLE_DAMAGE)
	e1:SetRange(LOCATION_PZONE)
	e1:SetCountLimit(1)
	e1:SetCondition(s.ddescon)
	e1:SetTarget(s.ddestg)
	e1:SetOperation(s.ddesop)
	c:RegisterEffect(e1)
	--direct attack
	local e2=Effect.CreateEffect(c)
	e2:SetType(EFFECT_TYPE_SINGLE)
	e2:SetCode(EFFECT_DIRECT_ATTACK)
	c:RegisterEffect(e2)
	--change position
	local e3=Effect.CreateEffect(c)
	e3:SetCategory(CATEGORY_POSITION)
	e3:SetType(EFFECT_TYPE_FIELD+EFFECT_TYPE_CONTINUOUS)
	e3:SetCode(EVENT_PHASE|PHASE_BATTLE)
	e3:SetCountLimit(1)
	e3:SetRange(LOCATION_MZONE)
	e3:SetCondition(s.poscon)
	e3:SetOperation(s.posop)
	c:RegisterEffect(e3)
end
function s.ddescon(e,tp,eg,ep,ev,re,r,rp)
	return ep~=tp and eg:GetFirst():IsControler(tp)
end
function s.ddestg(e,tp,eg,ep,ev,re,r,rp,chk)
	if chk==0 then return Duel.IsPlayerCanDiscardDeck(1-tp,1) end
	Duel.SetOperationInfo(0,CATEGORY_DECKDES,0,0,1-tp,1)
end
function s.ddesop(e,tp,eg,ep,ev,re,r,rp)
	if not e:GetHandler():IsRelateToEffect(e) then return end
	Duel.DiscardDeck(1-tp,1,REASON_EFFECT)
end
function s.poscon(e,tp,eg,ep,ev,re,r,rp)
	return e:GetHandler():GetAttackedCount()>0
end
function s.posop(e,tp,eg,ep,ev,re,r,rp)
	local c=e:GetHandler()
	if c:IsAttackPos() then
		Duel.ChangePosition(c,POS_FACEUP_DEFENSE)
	end
end