Generate a YGOPro Lua script for the following Yu-Gi-Oh card effect:
Each time a "Spellbook" Spell Card is activated, place 1 Spell Counter on this card. All Spellcaster-Type monsters you control gain 100 ATK for each Spell Counter on this card. When this card with Spell Counter(s) is destroyed and sent to the Graveyard: You can add 1 Spellcaster-Type monster from your Deck to your hand, whose Level is less than or equal to the number of Spell Counters that were on this card.
--魔導書廊エトワール
--Spellbook Star Hall
local s,id=GetID()
function s.initial_effect(c)
	c:EnableCounterPermit(COUNTER_SPELL)
	--Activate
	local e0=Effect.CreateEffect(c)
	e0:SetType(EFFECT_TYPE_ACTIVATE)
	e0:SetCode(EVENT_FREE_CHAIN)
	c:RegisterEffect(e0)
	--add counters
	local e1=Effect.CreateEffect(c)
	e1:SetType(EFFECT_TYPE_CONTINUOUS+EFFECT_TYPE_FIELD)
	e1:SetProperty(EFFECT_FLAG_CANNOT_DISABLE)
	e1:SetCode(EVENT_CHAINING)
	e1:SetRange(LOCATION_SZONE)
	e1:SetOperation(aux.chainreg)
	c:RegisterEffect(e1)
	local e2=Effect.CreateEffect(c)
	e2:SetType(EFFECT_TYPE_CONTINUOUS+EFFECT_TYPE_FIELD)
	e2:SetCode(EVENT_CHAIN_SOLVED)
	e2:SetRange(LOCATION_SZONE)
	e2:SetCondition(s.ctcon)
	e2:SetOperation(s.ctop)
	c:RegisterEffect(e2)
	--increase ATK
	local e3=Effect.CreateEffect(c)
	e3:SetType(EFFECT_TYPE_FIELD)
	e3:SetCode(EFFECT_UPDATE_ATTACK)
	e3:SetRange(LOCATION_SZONE)
	e3:SetTargetRange(LOCATION_MZONE,0)
	e3:SetTarget(aux.TargetBoolFunction(Card.IsRace,RACE_SPELLCASTER))
	e3:SetValue(s.atkval)
	c:RegisterEffect(e3)
	--registration before leaving
	local e4=Effect.CreateEffect(c)
	e4:SetType(EFFECT_TYPE_SINGLE+EFFECT_TYPE_CONTINUOUS)
	e4:SetCode(EVENT_LEAVE_FIELD_P)
	e4:SetProperty(EFFECT_FLAG_CANNOT_DISABLE)
	e4:SetOperation(s.regop)
	c:RegisterEffect(e4)
	--add a Spellcaster to hand
	local e5=Effect.CreateEffect(c)
	e5:SetDescription(aux.Stringid(id,0))
	e5:SetCategory(CATEGORY_TOHAND+CATEGORY_SEARCH)
	e5:SetType(EFFECT_TYPE_SINGLE+EFFECT_TYPE_TRIGGER_O)
	e5:SetProperty(EFFECT_FLAG_DAMAGE_STEP)
	e5:SetCode(EVENT_TO_GRAVE)
	e5:SetLabelObject(e4)
	e5:SetCondition(s.thcon)
	e5:SetTarget(s.thtg)
	e5:SetOperation(s.thop)
	c:RegisterEffect(e5)
end
s.listed_series={SET_SPELLBOOK}
s.counter_list={COUNTER_SPELL}
function s.ctcon(e,tp,eg,ep,ev,re,r,rp)
	if not re then return false end
	local c=re:GetHandler()
	return re:IsHasType(EFFECT_TYPE_ACTIVATE) and re:IsSpellEffect() and c:IsSetCard(SET_SPELLBOOK) and e:GetHandler():GetFlagEffect(1)>0
end
function s.ctop(e,tp,eg,ep,ev,re,r,rp)
	e:GetHandler():AddCounter(COUNTER_SPELL,1)
end
function s.atkval(e,c)
	return e:GetHandler():GetCounter(COUNTER_SPELL)*100
end
function s.regop(e,tp,eg,ep,ev,re,r,rp)
	local c=e:GetHandler()
	local ct=c:GetCounter(COUNTER_SPELL)
	e:SetLabel(ct)
end
function s.thcon(e,tp,eg,ep,ev,re,r,rp)
	local c=e:GetHandler()
	local ct=e:GetLabelObject():GetLabel()
	e:SetLabel(ct)
	return ct>0 and c:IsReason(REASON_DESTROY)
end
function s.filter(c,level)
	return c:IsMonster() and c:IsRace(RACE_SPELLCASTER) and c:IsLevelBelow(level) and c:IsAbleToHand()
end
function s.thtg(e,tp,eg,ep,ev,re,r,rp,chk)
	if chk==0 then return Duel.IsExistingMatchingCard(s.filter,tp,LOCATION_DECK,0,1,nil,e:GetLabel()) end
	Duel.SetOperationInfo(0,CATEGORY_TOHAND,nil,1,tp,LOCATION_DECK)
end
function s.thop(e,tp,eg,ep,ev,re,r,rp)
	Duel.Hint(HINT_SELECTMSG,tp,HINTMSG_ATOHAND)
	local g=Duel.SelectMatchingCard(tp,s.filter,tp,LOCATION_DECK,0,1,1,nil,e:GetLabel())
	if #g>0 then
		Duel.SendtoHand(g,nil,REASON_EFFECT)
		Duel.ConfirmCards(1-tp,g)
	end
end