Generate a YGOPro Lua script for the following Yu-Gi-Oh card effect:
Once per turn: You can choose a number from 1 to 3, then send that many cards from the top of your Deck to the GY; this card gains 500 ATK for each card sent to the GY this way, until the end of this turn. If this card you control is destroyed and sent to your GY: Draw 1 card.
--カードガンナー
--Card Trooper
local s,id=GetID()
function s.initial_effect(c)
	--atkup
	local e1=Effect.CreateEffect(c)
	e1:SetDescription(aux.Stringid(id,0))
	e1:SetCategory(CATEGORY_ATKCHANGE)
	e1:SetType(EFFECT_TYPE_IGNITION)
	e1:SetRange(LOCATION_MZONE)
	e1:SetCountLimit(1)
	e1:SetCost(s.cost)
	e1:SetOperation(s.operation)
	c:RegisterEffect(e1)
	--draw
	local e2=Effect.CreateEffect(c)
	e2:SetDescription(aux.Stringid(id,1))
	e2:SetCategory(CATEGORY_DRAW)
	e2:SetType(EFFECT_TYPE_SINGLE+EFFECT_TYPE_TRIGGER_F)
	e2:SetCode(EVENT_TO_GRAVE)
	e2:SetCondition(s.drcon)
	e2:SetTarget(s.drtg)
	e2:SetOperation(s.drop)
	c:RegisterEffect(e2)
end
function s.cost(e,tp,eg,ep,ev,re,r,rp,chk)
	if chk==0 then return Duel.IsPlayerCanDiscardDeckAsCost(tp,1) end
	local ct={}
	for i=3,1,-1 do
		if Duel.IsPlayerCanDiscardDeckAsCost(tp,i) then
			table.insert(ct,i)
		end
	end
	if #ct==1 then 
		Duel.DiscardDeck(tp,ct[1],REASON_COST)
		e:SetLabel(1)
	else
		Duel.Hint(HINT_SELECTMSG,tp,aux.Stringid(id,2))
		local ac=Duel.AnnounceNumber(tp,table.unpack(ct))
		Duel.DiscardDeck(tp,ac,REASON_COST)
		e:SetLabel(ac)
	end
end
function s.operation(e,tp,eg,ep,ev,re,r,rp)
	local c=e:GetHandler()
	if c:IsFaceup() and c:IsRelateToEffect(e) then
		local ct=e:GetLabel()
		local e1=Effect.CreateEffect(c)
		e1:SetType(EFFECT_TYPE_SINGLE)
		e1:SetCode(EFFECT_UPDATE_ATTACK)
		e1:SetReset(RESETS_STANDARD_DISABLE_PHASE_END)
		e1:SetValue(ct*500)
		c:RegisterEffect(e1)
	end
end
function s.drcon(e,tp,eg,ep,ev,re,r,rp)
	return (r&REASON_DESTROY)~=0 and e:GetHandler():IsPreviousControler(tp)
		and e:GetHandler():IsPreviousLocation(LOCATION_ONFIELD)
end
function s.drtg(e,tp,eg,ep,ev,re,r,rp,chk)
	if chk==0 then return true end
	Duel.SetTargetPlayer(tp)
	Duel.SetTargetParam(1)
	Duel.SetOperationInfo(0,CATEGORY_DRAW,nil,0,tp,1)
end
function s.drop(e,tp,eg,ep,ev,re,r,rp)
	local p,d=Duel.GetChainInfo(0,CHAININFO_TARGET_PLAYER,CHAININFO_TARGET_PARAM)
	Duel.Draw(p,d,REASON_EFFECT)
end