Generate a YGOPro Lua script for the following Yu-Gi-Oh card effect:
Once per turn: You can discard 1 Spellcaster-Type monster; draw 1 card. Once per turn, if this card is targeted for an attack: You can target 1 Spellcaster-Type monster in your Graveyard, except "Chocolate Magician Girl"; Special Summon it, then change the attack target to it, and if you do, the attacking monster's ATK becomes half its current ATK.
--チョコ・マジシャン・ガール
--Chocolate Magician Girl
local s,id=GetID()
function s.initial_effect(c)
	--draw
	local e1=Effect.CreateEffect(c)
	e1:SetDescription(aux.Stringid(id,0))
	e1:SetCategory(CATEGORY_DRAW)
	e1:SetType(EFFECT_TYPE_IGNITION)
	e1:SetRange(LOCATION_MZONE)
	e1:SetCountLimit(1)
	e1:SetCost(s.drcost)
	e1:SetTarget(s.drtg)
	e1:SetOperation(s.drop)
	c:RegisterEffect(e1)
	--change battle target
	local e2=Effect.CreateEffect(c)
	e2:SetDescription(aux.Stringid(id,1))
	e2:SetCategory(CATEGORY_SPECIAL_SUMMON+CATEGORY_ATKCHANGE)
	e2:SetType(EFFECT_TYPE_SINGLE+EFFECT_TYPE_TRIGGER_O)
	e2:SetProperty(EFFECT_FLAG_CARD_TARGET+EFFECT_FLAG_DELAY)
	e2:SetCode(EVENT_BE_BATTLE_TARGET)
	e2:SetCountLimit(1)
	e2:SetTarget(s.sptg)
	e2:SetOperation(s.spop)
	c:RegisterEffect(e2)
end
function s.costfilter(c)
	return c:IsRace(RACE_SPELLCASTER) and c:IsDiscardable()
end
function s.drcost(e,tp,eg,ep,ev,re,r,rp,chk)
	if chk==0 then return Duel.IsExistingMatchingCard(s.costfilter,tp,LOCATION_HAND,0,1,nil) end
	Duel.DiscardHand(tp,s.costfilter,1,1,REASON_DISCARD|REASON_COST)
end
function s.drtg(e,tp,eg,ep,ev,re,r,rp,chk)
	if chk==0 then return Duel.IsPlayerCanDraw(tp,1) 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
function s.spfilter(c,e,tp)
	return c:IsRace(RACE_SPELLCASTER) and not c:IsCode(id) and c:IsCanBeSpecialSummoned(e,0,tp,false,false)
end
function s.sptg(e,tp,eg,ep,ev,re,r,rp,chk,chkc)
	if chkc then return chkc:IsLocation(LOCATION_GRAVE) and chkc:IsControler(tp) and s.spfilter(chkc,e,tp) end
	if chk==0 then return Duel.GetLocationCount(tp,LOCATION_MZONE)>0
		and Duel.IsExistingTarget(s.spfilter,tp,LOCATION_GRAVE,0,1,nil,e,tp) end
	Duel.Hint(HINT_SELECTMSG,tp,HINTMSG_SPSUMMON)
	local g=Duel.SelectTarget(tp,s.spfilter,tp,LOCATION_GRAVE,0,1,1,nil,e,tp)
	Duel.SetOperationInfo(0,CATEGORY_SPECIAL_SUMMON,g,1,0,0)
end
function s.spop(e,tp,eg,ep,ev,re,r,rp)
	local tc=Duel.GetFirstTarget()
	if tc:IsRelateToEffect(e) and Duel.SpecialSummon(tc,0,tp,tp,false,false,POS_FACEUP)>0 then
		local a=Duel.GetAttacker()
		local ag=a:GetAttackableTarget()
		if a:CanAttack() and not a:IsImmuneToEffect(e) and ag:IsContains(tc) then
			Duel.BreakEffect()
			Duel.ChangeAttackTarget(tc)
			local e1=Effect.CreateEffect(e:GetHandler())
			e1:SetType(EFFECT_TYPE_SINGLE)
			e1:SetCode(EFFECT_SET_ATTACK_FINAL)
			e1:SetReset(RESET_EVENT|RESETS_STANDARD)
			e1:SetValue(math.ceil(a:GetAttack()/2))
			a:RegisterEffect(e1)
		end
	end
end