Generate a YGOPro Lua script for the following Yu-Gi-Oh card effect:
If this card attacks, it loses 300 ATK during the Damage Step only. If this card in your possession is destroyed by your opponent's card and sent to your GY: You can send 1 card from your hand to the GY, then target 1 Level 4 or lower Warrior monster in your GY; add that target to your hand.
--聖騎士ジャンヌ
--Noble Knight Joan
local s,id=GetID()
function s.initial_effect(c)
	--change ATK
	local e1=Effect.CreateEffect(c)
	e1:SetType(EFFECT_TYPE_SINGLE)
	e1:SetCode(EFFECT_UPDATE_ATTACK)
	e1:SetCondition(s.condtion)
	e1:SetValue(-300)
	c:RegisterEffect(e1)
	--salvage
	local e2=Effect.CreateEffect(c)
	e2:SetDescription(aux.Stringid(id,0))
	e2:SetCategory(CATEGORY_TOHAND)
	e2:SetProperty(EFFECT_FLAG_CARD_TARGET+EFFECT_FLAG_DAMAGE_STEP+EFFECT_FLAG_DELAY)
	e2:SetType(EFFECT_TYPE_SINGLE+EFFECT_TYPE_TRIGGER_O)
	e2:SetCode(EVENT_TO_GRAVE)
	e2:SetCondition(aux.dogcon)
	e2:SetCost(s.thcost)
	e2:SetTarget(s.thtg)
	e2:SetOperation(s.thop)
	c:RegisterEffect(e2)
end
function s.condtion(e)
	local ph=Duel.GetCurrentPhase()
	return (ph==PHASE_DAMAGE or ph==PHASE_DAMAGE_CAL) and Duel.GetAttacker()==e:GetHandler()
end
function s.thcost(e,tp,eg,ep,ev,re,r,rp,chk)
	if chk==0 then return Duel.IsExistingMatchingCard(Card.IsAbleToGraveAsCost,tp,LOCATION_HAND,0,1,nil) end
	Duel.DiscardHand(tp,Card.IsAbleToGraveAsCost,1,1,REASON_COST)
end
function s.filter(c)
	return c:IsLevelBelow(4) and c:IsRace(RACE_WARRIOR) and c:IsAbleToHand()
end
function s.thtg(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) end
	if chk==0 then return Duel.IsExistingTarget(s.filter,tp,LOCATION_GRAVE,0,1,nil) end
	Duel.Hint(HINT_SELECTMSG,tp,HINTMSG_ATOHAND)
	local g=Duel.SelectTarget(tp,s.filter,tp,LOCATION_GRAVE,0,1,1,nil)
	Duel.SetOperationInfo(0,CATEGORY_TOHAND,g,#g,0,0)
end
function s.thop(e,tp,eg,ep,ev,re,r,rp)
	local tc=Duel.GetFirstTarget()
	if tc and tc:IsRelateToEffect(e) then
		Duel.SendtoHand(tc,nil,REASON_EFFECT)
		Duel.ConfirmCards(1-tp,tc)
	end
end