Generate a YGOPro Lua script for the following Yu-Gi-Oh card effect:
Cannot be Normal Summoned/Set. Must be Special Summoned (from your hand or GY) by banishing 3 EARTH monsters from your hand and/or GY. Rock monsters you control cannot be destroyed, except by battle. If this card is sent from the field to the GY: You can add up to 3 Rock monsters from your Deck to your hand, whose total Levels equal 8. You can only use this effect of "Block Dragon" once per turn.
--ブロックドラゴン
--Block Dragon
local s,id=GetID()
function s.initial_effect(c)
	c:EnableReviveLimit()
	--special summon condition
	local e1=Effect.CreateEffect(c)
	e1:SetType(EFFECT_TYPE_SINGLE)
	e1:SetProperty(EFFECT_FLAG_CANNOT_DISABLE+EFFECT_FLAG_UNCOPYABLE)
	e1:SetCode(EFFECT_SPSUMMON_CONDITION)
	c:RegisterEffect(e1)
	--special summon
	local e2=Effect.CreateEffect(c)
	e2:SetType(EFFECT_TYPE_FIELD)
	e2:SetCode(EFFECT_SPSUMMON_PROC)
	e2:SetProperty(EFFECT_FLAG_CANNOT_DISABLE+EFFECT_FLAG_UNCOPYABLE)
	e2:SetRange(LOCATION_HAND|LOCATION_GRAVE)
	e2:SetTarget(s.sptg)
	e2:SetCondition(s.spcon)
	e2:SetOperation(s.spop)
	c:RegisterEffect(e2)
	--indes
	local e3=Effect.CreateEffect(c)
	e3:SetType(EFFECT_TYPE_FIELD)
	e3:SetCode(EFFECT_INDESTRUCTABLE)
	e3:SetRange(LOCATION_MZONE)
	e3:SetTargetRange(LOCATION_MZONE,0)
	e3:SetTarget(aux.TargetBoolFunction(Card.IsRace,RACE_ROCK))
	e3:SetValue(s.indesval)
	c:RegisterEffect(e3)
	--to hand
	local e4=Effect.CreateEffect(c)
	e4:SetDescription(aux.Stringid(id,0))
	e4:SetCategory(CATEGORY_TOHAND+CATEGORY_SEARCH)
	e4:SetType(EFFECT_TYPE_SINGLE+EFFECT_TYPE_TRIGGER_O)
	e4:SetProperty(EFFECT_FLAG_DELAY)
	e4:SetCode(EVENT_TO_GRAVE)
	e4:SetCountLimit(1,id)
	e4:SetCondition(s.thcon)
	e4:SetTarget(s.thtg)
	e4:SetOperation(s.thop)
	c:RegisterEffect(e4)
end
function s.spfilter(c)
	return c:IsAttribute(ATTRIBUTE_EARTH) and c:IsAbleToRemoveAsCost() and (c:IsLocation(LOCATION_HAND) or aux.SpElimFilter(c,true))
end
function s.spcon(e,c)
	if c==nil then return true end
	local tp=c:GetControler()
	local g=Duel.GetMatchingGroup(s.spfilter,tp,LOCATION_GRAVE|LOCATION_MZONE|LOCATION_HAND,0,e:GetHandler())
	return aux.SelectUnselectGroup(g,e,tp,3,3,aux.ChkfMMZ(1),0) and Duel.GetLocationCount(tp,LOCATION_MZONE)>0
end
function s.sptg(e,tp,eg,ep,ev,re,r,rp,chk,c)
	local g=Duel.GetMatchingGroup(s.spfilter,tp,LOCATION_GRAVE|LOCATION_MZONE|LOCATION_HAND,0,e:GetHandler())
	local rg=aux.SelectUnselectGroup(g,e,tp,3,3,aux.ChkfMMZ(1),1,tp,HINTMSG_REMOVE,nil,nil,true)
	if #rg>0 then
		rg:KeepAlive()
		e:SetLabelObject(rg)
		return true
	end
	return false
end
function s.spop(e,tp,eg,ep,ev,re,r,rp,c)
	local rg=e:GetLabelObject()
	if not rg then return end
	Duel.Remove(rg,POS_FACEUP,REASON_COST)
	rg:DeleteGroup()
end
function s.indesval(e,re,r,rp)
	return (r&REASON_BATTLE)==0
end
function s.thcon(e,tp,eg,ep,ev,re,r,rp)
	return e:GetHandler():IsPreviousLocation(LOCATION_ONFIELD)
end
function s.thfilter(c)
	return c:IsRace(RACE_ROCK) and c:IsAbleToHand()
end
function s.thtg(e,tp,eg,ep,ev,re,r,rp,chk)
	local g=Duel.GetMatchingGroup(s.thfilter,tp,LOCATION_DECK,0,nil)
	if chk==0 then return g:CheckWithSumEqual(Card.GetLevel,8,1,3) end
	Duel.SetOperationInfo(0,CATEGORY_TOHAND,nil,1,tp,LOCATION_DECK)
end
function s.thop(e,tp,eg,ep,ev,re,r,rp)
	local g=Duel.GetMatchingGroup(s.thfilter,tp,LOCATION_DECK,0,nil)
	Duel.Hint(HINT_SELECTMSG,tp,HINTMSG_ATOHAND)
	local sg=g:SelectWithSumEqual(tp,Card.GetLevel,8,1,3)
	if sg and #sg>0 then
		Duel.SendtoHand(sg,nil,REASON_EFFECT)
		Duel.ConfirmCards(1-tp,sg)
	end
end