Generate a YGOPro Lua script for the following Yu-Gi-Oh card effect:
If this card is Normal or Special Summoned: You can halve this card's ATK, and if you do, Special Summon 1 "Clock Token" (Cyberse/WIND/Level 1/ATK 0/DEF 0). You can only use this effect of "Clock Wyvern" once per turn.
--クロック・ワイバーン
--Clock Wyvern
--scripted by Larry126
local s,id=GetID()
function s.initial_effect(c)
	--token
	local e1=Effect.CreateEffect(c)
	e1:SetProperty(EFFECT_FLAG_DELAY)
	e1:SetDescription(aux.Stringid(id,0))
	e1:SetCategory(CATEGORY_SPECIAL_SUMMON+CATEGORY_TOKEN+CATEGORY_ATKCHANGE)
	e1:SetType(EFFECT_TYPE_SINGLE+EFFECT_TYPE_TRIGGER_O)
	e1:SetCode(EVENT_SUMMON_SUCCESS)
	e1:SetCountLimit(1,id)
	e1:SetTarget(s.tktg)
	e1:SetOperation(s.tkop)
	c:RegisterEffect(e1)
	local e2=e1:Clone()
	e2:SetCode(EVENT_SPSUMMON_SUCCESS)
	c:RegisterEffect(e2)
end
s.listed_names={21830680}
function s.tktg(e,tp,eg,ep,ev,re,r,rp,chk)
	if chk==0 then return Duel.GetLocationCount(tp,LOCATION_MZONE)>0
		and Duel.IsPlayerCanSpecialSummonMonster(tp,id+1,0,TYPES_TOKEN,0,0,1,RACE_CYBERSE,ATTRIBUTE_WIND) end
	local c=e:GetHandler()
	Duel.SetOperationInfo(0,CATEGORY_SPECIAL_SUMMON,nil,1,0,0)
	Duel.SetOperationInfo(0,CATEGORY_TOKEN,nil,1,0,0)
	Duel.SetOperationInfo(0,CATEGORY_ATKCHANGE,c,1,tp,c:GetAttack()/2)
end
function s.tkop(e,tp,eg,ep,ev,re,r,rp)
	local c=e:GetHandler()
	if c:IsRelateToEffect(e) and c:IsFaceup() then
		local e1=Effect.CreateEffect(c)
		e1:SetType(EFFECT_TYPE_SINGLE)
		e1:SetCode(EFFECT_SET_ATTACK_FINAL)
		e1:SetValue(c:GetAttack()/2)
		e1:SetReset(RESET_EVENT|RESETS_STANDARD)
		c:RegisterEffect(e1)
		if not c:IsImmuneToEffect(e1) and Duel.GetLocationCount(tp,LOCATION_MZONE)>0
			and Duel.IsPlayerCanSpecialSummonMonster(tp,id+1,0,TYPES_TOKEN,0,0,1,RACE_CYBERSE,ATTRIBUTE_WIND) then
			local token=Duel.CreateToken(tp,id+1)
			Duel.SpecialSummon(token,0,tp,tp,false,false,POS_FACEUP)
		end
	end
end