Generate a YGOPro Lua script for the following Yu-Gi-Oh card effect:
You can Tribute 1 monster, or no monsters, to Normal Summon (but not Set) this card. The ATK of this card becomes the combined original ATK of the Tributed monsters. Neither player can Tribute cards.
--霧の王
--Fog King
local s,id=GetID()
function s.initial_effect(c)
	--summon with 1 tribute
	local e0=Effect.CreateEffect(c)
	e0:SetDescription(aux.Stringid(id,0))
	e0:SetType(EFFECT_TYPE_SINGLE)
	e0:SetCode(EFFECT_SUMMON_PROC)
	e0:SetCondition(s.ttcon)
	e0:SetOperation(s.ttop)
	e0:SetValue(SUMMON_TYPE_TRIBUTE)
	c:RegisterEffect(e0)
	--summon with no tribute
	local e1=Effect.CreateEffect(c)
	e1:SetDescription(aux.Stringid(id,1))
	e1:SetType(EFFECT_TYPE_SINGLE)
	e1:SetCode(EFFECT_SUMMON_PROC)
	e1:SetCondition(s.ntcon)
	c:RegisterEffect(e1)
	--tribute check
	local e2=Effect.CreateEffect(c)
	e2:SetType(EFFECT_TYPE_SINGLE)
	e2:SetCode(EFFECT_MATERIAL_CHECK)
	e2:SetValue(s.valcheck)
	c:RegisterEffect(e2)
	--give atk effect only when summon
	local e3=Effect.CreateEffect(c)
	e3:SetType(EFFECT_TYPE_SINGLE)
	e3:SetCode(EFFECT_SUMMON_COST)
	e3:SetOperation(s.facechk)
	e3:SetLabelObject(e2)
	c:RegisterEffect(e3)
	--cannot release
	local e4=Effect.CreateEffect(c)
	e4:SetType(EFFECT_TYPE_FIELD)
	e4:SetRange(LOCATION_MZONE)
	e4:SetCode(EFFECT_CANNOT_RELEASE)
	e4:SetProperty(EFFECT_FLAG_PLAYER_TARGET)
	e4:SetTargetRange(1,1)
	c:RegisterEffect(e4)
end
function s.ntcon(e,c,minc)
	if c==nil then return true end
	return minc==0 and c:GetLevel()>4 and Duel.GetLocationCount(c:GetControler(),LOCATION_MZONE)>0
end
function s.ttcon(e,c,minc)
	if c==nil then return true end
	return minc<=1 and Duel.CheckTribute(c,1)
end
function s.ttop(e,tp,eg,ep,ev,re,r,rp,c)
	Duel.Hint(HINT_SELECTMSG,tp,HINTMSG_RELEASE)
	local g=Duel.SelectTribute(tp,c,1,1)
	c:SetMaterial(g)
	Duel.Release(g, REASON_SUMMON+REASON_MATERIAL)
end
function s.valcheck(e,c)
	local g=c:GetMaterial()
	local tc=g:GetFirst()
	local atk=0
	for tc in aux.Next(g) do
		local catk=tc:GetTextAttack()
		atk=atk+(catk>=0 and catk or 0)
	end
	if e:GetLabel()==1 then
		e:SetLabel(0)
		local e1=Effect.CreateEffect(c)
		e1:SetType(EFFECT_TYPE_SINGLE)
		e1:SetCode(EFFECT_SET_ATTACK)
		e1:SetValue(atk)
		e1:SetReset(RESET_EVENT|RESET_DISABLE|RESET_TURN_SET|RESET_TOGRAVE|RESET_REMOVE|RESET_TEMP_REMOVE|RESET_TOHAND|RESET_TODECK|RESET_LEAVE)
		c:RegisterEffect(e1)
	end
end
function s.facechk(e,tp,eg,ep,ev,re,r,rp)
	e:GetLabelObject():SetLabel(1)
end