Generate a YGOPro Lua script for the following Yu-Gi-Oh card effect:
Once per turn, during either player's Main Phase: You can target 1 face-up monster on the field; switch its current ATK and DEF until the end of this turn.
--EMウィップ・バイパー
--Performapal Whip Snake
local s,id=GetID()
function s.initial_effect(c)
	--swap
	local e1=Effect.CreateEffect(c)
	e1:SetDescription(aux.Stringid(id,0))
	e1:SetType(EFFECT_TYPE_QUICK_O)
	e1:SetCode(EVENT_FREE_CHAIN)
	e1:SetRange(LOCATION_MZONE)
	e1:SetProperty(EFFECT_FLAG_CARD_TARGET)
	e1:SetHintTiming(0,TIMING_MAIN_END)
	e1:SetCountLimit(1)
	e1:SetCondition(s.condition)
	e1:SetTarget(s.target)
	e1:SetOperation(s.operation)
	c:RegisterEffect(e1)
end
function s.condition(e,tp,eg,ep,ev,re,r,rp)
	local ph=Duel.GetCurrentPhase()
	return Duel.IsMainPhase()
end
function s.filter(c)
	return c:IsFaceup() and c:IsDefenseAbove(0)
end
function s.target(e,tp,eg,ep,ev,re,r,rp,chk,chkc)
	if chkc then return chkc:IsControler(tp) and chkc:IsLocation(LOCATION_MZONE) and s.filter(chkc) end
	if chk==0 then return Duel.IsExistingTarget(s.filter,tp,LOCATION_MZONE,LOCATION_MZONE,1,nil) end
	Duel.Hint(HINT_SELECTMSG,tp,HINTMSG_FACEUP)
	Duel.SelectTarget(tp,s.filter,tp,LOCATION_MZONE,LOCATION_MZONE,1,1,nil)
end
function s.operation(e,tp,eg,ep,ev,re,r,rp)
	local tc=Duel.GetFirstTarget()
	if tc:IsFaceup() and tc:IsRelateToEffect(e) then
		local atk=tc:GetAttack()
		local def=tc:GetDefense()
		local e1=Effect.CreateEffect(e:GetHandler())
		e1:SetType(EFFECT_TYPE_SINGLE)
		e1:SetCode(EFFECT_SWAP_ATTACK_FINAL)
		e1:SetProperty(EFFECT_FLAG_CANNOT_DISABLE)
		e1:SetValue(def)
		e1:SetReset(RESETS_STANDARD_PHASE_END)
		tc:RegisterEffect(e1)
		local e2=e1:Clone()
		e2:SetCode(EFFECT_SWAP_DEFENSE_FINAL)
		e2:SetValue(atk)
		tc:RegisterEffect(e2)
	end
end