Generate a YGOPro Lua script for the following Yu-Gi-Oh card effect:
This card can only be summoned by a Flip Summon. If summoned by a Normal Summon, the card is destroyed. If your opponent has 1 or more monsters under his/her control, the ATK of this card is decreased by 1000 points.
--ボアソルジャー
--Boar Soldier
local s,id=GetID()
function s.initial_effect(c)
	--self destroy
	local e1=Effect.CreateEffect(c)
	e1:SetCategory(CATEGORY_DESTROY)
	e1:SetType(EFFECT_TYPE_SINGLE+EFFECT_TYPE_TRIGGER_F)
	e1:SetCode(EVENT_SUMMON_SUCCESS)
	e1:SetTarget(s.destg)
	e1:SetOperation(s.desop)
	c:RegisterEffect(e1)
	--atk down
	local e2=Effect.CreateEffect(c)
	e2:SetType(EFFECT_TYPE_SINGLE)
	e2:SetProperty(EFFECT_FLAG_SINGLE_RANGE)
	e2:SetRange(LOCATION_MZONE)
	e2:SetCode(EFFECT_UPDATE_ATTACK)
	e2:SetCondition(s.con)
	e2:SetValue(-1000)
	c:RegisterEffect(e2)
end
function s.destg(e,tp,eg,ep,ev,re,r,rp,chk)
	if chk==0 then return true end
	Duel.SetOperationInfo(0,CATEGORY_DESTROY,e:GetHandler(),1,0,0)
end
function s.desop(e,tp,eg,ep,ev,re,r,rp)
	if e:GetHandler():IsRelateToEffect(e) then
		Duel.Destroy(e:GetHandler(),REASON_EFFECT)
	end
end
function s.con(e)
	return Duel.GetFieldGroupCount(e:GetHandlerPlayer(),0,LOCATION_MZONE)>0
end