Generate a YGOPro Lua script for the following Yu-Gi-Oh card effect:
Cannot be Normal Summoned/Set. Must be Special Summoned by a card effect. (Quick Effect): You can target 1 Machine monster you control; destroy both that Machine monster and all monsters your opponent controls with ATK less than or equal to it. If a face-up EARTH Machine monster(s) you control, except "Machina Citadel", is destroyed by battle or card effect while this card is in your GY: You can Special Summon this card. You can only use each effect of "Machina Citadel" once per turn. * The above text is unofficial and describes the card's functionality in the OCG.
--マシンナーズ・カーネル
--Machina Citadel
--Scripted by AlphaKretin
local s,id=GetID()
function s.initial_effect(c)
	c:EnableUnsummonable()
	c:AddMustBeSpecialSummonedByCardEffect()
	--Destroy 1 Machine monster you control and all monsters your opponent controls with ATK less than or equal to it
	local e1=Effect.CreateEffect(c)
	e1:SetDescription(aux.Stringid(id,0))
	e1:SetCategory(CATEGORY_DESTROY)
	e1:SetType(EFFECT_TYPE_QUICK_O)
	e1:SetProperty(EFFECT_FLAG_CARD_TARGET)
	e1:SetCode(EVENT_FREE_CHAIN)
	e1:SetRange(LOCATION_MZONE)
	e1:SetCountLimit(1,id)
	e1:SetHintTiming(0,TIMING_STANDBY_PHASE|TIMING_MAIN_END|TIMINGS_CHECK_MONSTER_E)
	e1:SetTarget(s.destg)
	e1:SetOperation(s.desop)
	c:RegisterEffect(e1)
	--Special Summon this card
	local e2=Effect.CreateEffect(c)
	e2:SetDescription(aux.Stringid(id,1))
	e2:SetCategory(CATEGORY_SPECIAL_SUMMON)
	e2:SetType(EFFECT_TYPE_FIELD+EFFECT_TYPE_TRIGGER_O)
	e2:SetProperty(EFFECT_FLAG_DELAY+EFFECT_FLAG_DAMAGE_STEP,EFFECT_FLAG2_CHECK_SIMULTANEOUS)
	e2:SetCode(EVENT_DESTROYED)
	e2:SetRange(LOCATION_GRAVE)
	e2:SetCountLimit(1,{id,1})
	e2:SetCondition(s.spcon)
	e2:SetTarget(s.sptg)
	e2:SetOperation(s.spop)
	c:RegisterEffect(e2)
end
s.listed_names={id}
function s.desfilter(c,tp)
	return c:IsRace(RACE_MACHINE) and c:IsFaceup() and Duel.IsExistingMatchingCard(aux.FaceupFilter(Card.IsAttackBelow,c:GetAttack()),tp,0,LOCATION_MZONE,1,nil)
end
function s.destg(e,tp,eg,ep,ev,re,r,rp,chk,chkc)
	if chkc then return chkc:IsLocation(LOCATION_MZONE) and chkc:IsControler(tp) and s.desfilter(chkc,tp) end
	if chk==0 then return Duel.IsExistingTarget(s.desfilter,tp,LOCATION_MZONE,0,1,nil,tp) end
	Duel.Hint(HINT_SELECTMSG,tp,HINTMSG_DESTROY)
	local tc=Duel.SelectTarget(tp,s.desfilter,tp,LOCATION_MZONE,0,1,1,nil,tp):GetFirst()
	local dg=tc+Duel.GetMatchingGroup(aux.FaceupFilter(Card.IsAttackBelow,tc:GetAttack()),tp,0,LOCATION_MZONE,nil)
	Duel.SetOperationInfo(0,CATEGORY_DESTROY,dg,#dg,tp,0)
end
function s.desop(e,tp,eg,ep,ev,re,r,rp)
	local tc=Duel.GetFirstTarget()
	if tc:IsRelateToEffect(e) and tc:IsRace(RACE_MACHINE) and tc:IsFaceup() then
		local g=Duel.GetMatchingGroup(aux.FaceupFilter(Card.IsAttackBelow,tc:GetAttack()),tp,0,LOCATION_MZONE,nil)
		if #g>0 then
			Duel.Destroy(g+tc,REASON_EFFECT)
		end
	end
end
function s.spconfilter(c,tp)
	return c:IsPreviousAttributeOnField(ATTRIBUTE_EARTH) and c:IsPreviousRaceOnField(RACE_MACHINE) and c:IsPreviousPosition(POS_FACEUP)
		and c:IsPreviousControler(tp) and c:IsPreviousLocation(LOCATION_MZONE) and not c:IsPreviousCodeOnField(id)
		and c:IsReason(REASON_BATTLE|REASON_EFFECT)
end
function s.spcon(e,tp,eg,ep,ev,re,r,rp)
	return not eg:IsContains(e:GetHandler()) and eg:IsExists(s.spconfilter,1,nil,tp)
end
function s.sptg(e,tp,eg,ep,ev,re,r,rp,chk)
	local c=e:GetHandler()
	if chk==0 then return Duel.GetLocationCount(tp,LOCATION_MZONE)>0
		and c:IsCanBeSpecialSummoned(e,0,tp,false,false) end
	Duel.SetOperationInfo(0,CATEGORY_SPECIAL_SUMMON,c,1,tp,0)
end
function s.spop(e,tp,eg,ep,ev,re,r,rp)
	local c=e:GetHandler()
	if c:IsRelateToEffect(e) then
		Duel.SpecialSummon(c,0,tp,tp,false,false,POS_FACEUP)
	end
end