Generate a YGOPro Lua script for the following Yu-Gi-Oh card effect:
1 "Elemental HERO" monster + 1 EARTH monster Must be Fusion Summoned and cannot be Special Summoned by other ways. When this card is Fusion Summoned: Target 1 face-up monster your opponent controls; until the End Phase, its ATK is halved and this card gains the same amount of ATK.
--E・HERO ガイア
--Elemental HERO Gaia
local s,id=GetID()
function s.initial_effect(c)
	--fusion material
	c:EnableReviveLimit()
	Fusion.AddProcMix(c,true,true,aux.FilterBoolFunctionEx(Card.IsSetCard,SET_ELEMENTAL_HERO),aux.FilterBoolFunctionEx(Card.IsAttribute,ATTRIBUTE_EARTH))
	--atk up
	local e2=Effect.CreateEffect(c)
	e2:SetDescription(aux.Stringid(id,0))
	e2:SetCategory(CATEGORY_ATKCHANGE)
	e2:SetType(EFFECT_TYPE_SINGLE+EFFECT_TYPE_TRIGGER_F)
	e2:SetProperty(EFFECT_FLAG_CARD_TARGET)
	e2:SetCode(EVENT_SPSUMMON_SUCCESS)
	e2:SetCondition(s.atkcon)
	e2:SetTarget(s.atktg)
	e2:SetOperation(s.atkop)
	c:RegisterEffect(e2)
	--spsummon condition
	local e3=Effect.CreateEffect(c)
	e3:SetType(EFFECT_TYPE_SINGLE)
	e3:SetProperty(EFFECT_FLAG_CANNOT_DISABLE+EFFECT_FLAG_UNCOPYABLE)
	e3:SetCode(EFFECT_SPSUMMON_CONDITION)
	e3:SetValue(aux.fuslimit)
	c:RegisterEffect(e3)
end
s.listed_series={SET_ELEMENTAL_HERO}
s.material_setcode={SET_HERO,SET_ELEMENTAL_HERO}
function s.atkcon(e,tp,eg,ep,ev,re,r,rp)
	return e:GetHandler():IsFusionSummoned()
end
function s.atktg(e,tp,eg,ep,ev,re,r,rp,chk,chkc)
	if chkc then return chkc:IsControler(1-tp) and chkc:IsLocation(LOCATION_MZONE) and chkc:IsFaceup() end
	if chk==0 then return true end
	Duel.Hint(HINT_SELECTMSG,tp,HINTMSG_FACEUP)
	local g=Duel.SelectTarget(tp,Card.IsFaceup,tp,0,LOCATION_MZONE,1,1,nil)
	Duel.SetOperationInfo(0,CATEGORY_ATKCHANGE,g,#g,0,0)
end
function s.atkop(e,tp,eg,ep,ev,re,r,rp)
	local c=e:GetHandler()
	local tc=Duel.GetFirstTarget()
	if tc and tc:IsRelateToEffect(e) and tc:IsFaceup() and not tc:IsImmuneToEffect(e) then
		local atk=tc:GetAttack()
		local e1=Effect.CreateEffect(c)
		e1:SetType(EFFECT_TYPE_SINGLE)
		e1:SetCode(EFFECT_SET_ATTACK_FINAL)
		e1:SetValue(atk/2)
		e1:SetReset(RESETS_STANDARD_PHASE_END)
		tc:RegisterEffect(e1)
		if c:IsRelateToEffect(e) and c:IsFaceup() then
			local e2=Effect.CreateEffect(c)
			e2:SetType(EFFECT_TYPE_SINGLE)
			e2:SetCode(EFFECT_UPDATE_ATTACK)
			e2:SetProperty(EFFECT_FLAG_CANNOT_DISABLE)
			e2:SetValue(atk/2)
			e2:SetReset(RESETS_STANDARD_PHASE_END)
			c:RegisterEffect(e2)
		end
	end
end