Generate a YGOPro Lua script for the following Yu-Gi-Oh card effect:
FLIP: You gain 500 LP for each "Galaxy" monster in your Graveyard. When this card is destroyed and sent from the field to the Graveyard after being flipped face-up: You can Special Summon 1 Level 4 or lower "Galaxy" monster from your Deck or Graveyard in face-down Defense Position. Banish it when it leaves the field.
--銀河魔鏡士
--Galaxy Mirror Sage
local s,id=GetID()
function s.initial_effect(c)
	--Gain 500 LP per "Galaxy" monster in your GY
	local e1=Effect.CreateEffect(c)
	e1:SetDescription(aux.Stringid(id,0))
	e1:SetCategory(CATEGORY_RECOVER)
	e1:SetType(EFFECT_TYPE_SINGLE+EFFECT_TYPE_FLIP)
	e1:SetProperty(EFFECT_FLAG_PLAYER_TARGET)
	e1:SetTarget(s.rectg)
	e1:SetOperation(s.recop)
	c:RegisterEffect(e1)
	--Register the fact it was flipped face-up
	local e2=Effect.CreateEffect(c)
	e2:SetType(EFFECT_TYPE_SINGLE+EFFECT_TYPE_CONTINUOUS)
	e2:SetCode(EVENT_FLIP)
	e2:SetProperty(EFFECT_FLAG_CANNOT_DISABLE)
	e2:SetOperation(s.flipop)
	c:RegisterEffect(e2)
	--Special summon 1 level 4 or lower "Galaxy" monster from deck
	local e3=Effect.CreateEffect(c)
	e3:SetDescription(aux.Stringid(id,1))
	e3:SetCategory(CATEGORY_SPECIAL_SUMMON)
	e3:SetType(EFFECT_TYPE_SINGLE+EFFECT_TYPE_TRIGGER_O)
	e3:SetCode(EVENT_TO_GRAVE)
	e3:SetProperty(EFFECT_FLAG_DAMAGE_STEP)
	e3:SetCondition(s.spcon)
	e3:SetTarget(s.sptg)
	e3:SetOperation(s.spop)
	c:RegisterEffect(e3)
end
s.listed_series={SET_GALAXY}
function s.filter(c)
	return c:IsSetCard(SET_GALAXY) and c:IsMonster()
end
function s.rectg(e,tp,eg,ep,ev,re,r,rp,chk)
	if chk==0 then return true end
	local val=Duel.GetMatchingGroupCount(s.filter,tp,LOCATION_GRAVE,0,nil)*500
	Duel.SetTargetPlayer(tp)
	Duel.SetTargetParam(val)
	Duel.SetOperationInfo(0,CATEGORY_RECOVER,nil,0,tp,val)
end
function s.recop(e,tp,eg,ep,ev,re,r,rp)
	local val=Duel.GetMatchingGroupCount(s.filter,tp,LOCATION_GRAVE,0,nil)*500
	local p=Duel.GetChainInfo(0,CHAININFO_TARGET_PLAYER)
	Duel.Recover(p,val,REASON_EFFECT)
end
function s.flipop(e,tp,eg,ep,ev,re,r,rp)
	e:GetHandler():RegisterFlagEffect(id,(RESET_EVENT|RESETS_STANDARD|RESET_OVERLAY)&~(RESET_LEAVE|RESET_TOGRAVE),0,0)
end
function s.spcon(e,tp,eg,ep,ev,re,r,rp)
	return e:GetHandler():GetFlagEffect(id)~=0 and e:GetHandler():IsReason(REASON_DESTROY)
end
function s.spfilter(c,e,tp)
	return c:IsSetCard(SET_GALAXY) and c:IsLevelBelow(4) and c:IsCanBeSpecialSummoned(e,0,tp,false,false,POS_FACEDOWN_DEFENSE)
end
function s.sptg(e,tp,eg,ep,ev,re,r,rp,chk)
	if chk==0 then return Duel.GetLocationCount(tp,LOCATION_MZONE)>0
		and Duel.IsExistingMatchingCard(s.spfilter,tp,LOCATION_DECK|LOCATION_GRAVE,0,1,nil,e,tp) end
	Duel.SetOperationInfo(0,CATEGORY_SPECIAL_SUMMON,nil,1,tp,LOCATION_DECK|LOCATION_GRAVE)
end
function s.spop(e,tp,eg,ep,ev,re,r,rp)
	if Duel.GetLocationCount(tp,LOCATION_MZONE)<=0 then return end
	Duel.Hint(HINT_SELECTMSG,tp,HINTMSG_SPSUMMON)
	local tc=Duel.SelectMatchingCard(tp,aux.NecroValleyFilter(s.spfilter),tp,LOCATION_DECK|LOCATION_GRAVE,0,1,1,nil,e,tp):GetFirst()
	if not tc then return end
	if Duel.SpecialSummonStep(tc,0,tp,tp,false,false,POS_FACEDOWN_DEFENSE) then
		--Banish it if it leaves the field
		local e1=Effect.CreateEffect(e:GetHandler())
		e1:SetDescription(3300)
		e1:SetType(EFFECT_TYPE_SINGLE)
		e1:SetCode(EFFECT_LEAVE_FIELD_REDIRECT)
		e1:SetProperty(EFFECT_FLAG_CANNOT_DISABLE+EFFECT_FLAG_CLIENT_HINT)
		e1:SetReset(RESET_EVENT|RESETS_REDIRECT)
		e1:SetValue(LOCATION_REMOVED)
		tc:RegisterEffect(e1,true)
	end
	Duel.SpecialSummonComplete()
	Duel.ConfirmCards(1-tp,tc)
end