Generate a YGOPro Lua script for the following Yu-Gi-Oh card effect:
If only your opponent controls a monster, you can Special Summon this card (from your hand), but its original ATK/DEF become halved.
--バイス・ドラゴン
--Vice Dragon
local s,id=GetID()
function s.initial_effect(c)
	--special summon
	local e1=Effect.CreateEffect(c)
	e1:SetType(EFFECT_TYPE_FIELD)
	e1:SetCode(EFFECT_SPSUMMON_PROC)
	e1:SetProperty(EFFECT_FLAG_UNCOPYABLE)
	e1:SetRange(LOCATION_HAND)
	e1:SetCondition(s.spcon)
	e1:SetOperation(s.spop)
	c:RegisterEffect(e1)
end
function s.spcon(e,c)
	if c==nil then return true end
	return Duel.GetFieldGroupCount(c:GetControler(),LOCATION_MZONE,0,nil)==0
		and	Duel.GetFieldGroupCount(c:GetControler(),0,LOCATION_MZONE,nil)>0
		and Duel.GetLocationCount(c:GetControler(),LOCATION_MZONE)>0
end
function s.spop(e,tp,eg,ep,ev,re,r,rp,c)
	local e1=Effect.CreateEffect(c)
	e1:SetType(EFFECT_TYPE_SINGLE)
	e1:SetCode(EFFECT_SET_BASE_ATTACK)
	e1:SetValue(1000)
	e1:SetReset(RESET_EVENT|RESETS_STANDARD_DISABLE&~RESET_TOFIELD)
	c:RegisterEffect(e1)
	local e2=Effect.CreateEffect(c)
	e2:SetType(EFFECT_TYPE_SINGLE)
	e2:SetCode(EFFECT_SET_BASE_DEFENSE)
	e2:SetValue(1200)
	e2:SetReset(RESET_EVENT|(RESETS_STANDARD_DISABLE&~RESET_TOFIELD))
	c:RegisterEffect(e2)
end