Generate a YGOPro Lua script for the following Yu-Gi-Oh card effect:
If you control a Dragon monster: Activate 1 of these effects; ● Inflict 800 damage to your opponent. ● Target 1 monster with 800 or less DEF; destroy that target.
--火竜の火炎弾
--Dragon's Gunfire
local s,id=GetID()
function s.initial_effect(c)
	--damage
	local e1=Effect.CreateEffect(c)
	e1:SetDescription(aux.Stringid(id,0))
	e1:SetType(EFFECT_TYPE_ACTIVATE)
	e1:SetCategory(CATEGORY_DAMAGE)
	e1:SetProperty(EFFECT_FLAG_PLAYER_TARGET)
	e1:SetCode(EVENT_FREE_CHAIN)
	e1:SetCondition(s.condition)
	e1:SetTarget(s.damtg)
	e1:SetOperation(s.damop)
	c:RegisterEffect(e1)
	--destroy
	local e2=Effect.CreateEffect(c)
	e2:SetDescription(aux.Stringid(id,1))
	e2:SetCategory(CATEGORY_DESTROY)
	e2:SetType(EFFECT_TYPE_ACTIVATE)
	e2:SetProperty(EFFECT_FLAG_CARD_TARGET)
	e2:SetCode(EVENT_FREE_CHAIN)
	e2:SetCondition(s.condition)
	e2:SetTarget(s.destg)
	e2:SetOperation(s.desop)
	c:RegisterEffect(e2)
end
function s.condition(e,tp,eg,ep,ev,re,r,rp)
	return Duel.IsExistingMatchingCard(aux.FaceupFilter(Card.IsRace,RACE_DRAGON),tp,LOCATION_MZONE,0,1,nil)
end
function s.damtg(e,tp,eg,ep,ev,re,r,rp,chk)
	if chk==0 then return true end
	Duel.Hint(HINT_OPSELECTED,1-tp,e:GetDescription())
	Duel.SetTargetPlayer(1-tp)
	Duel.SetTargetParam(800)
	Duel.SetOperationInfo(0,CATEGORY_DAMAGE,nil,0,1-tp,800)
end
function s.damop(e,tp,eg,ep,ev,re,r,rp)
	local p,d=Duel.GetChainInfo(0,CHAININFO_TARGET_PLAYER,CHAININFO_TARGET_PARAM)
	Duel.Damage(p,d,REASON_EFFECT)
end
function s.dfilter(c)
	return c:IsFaceup() and c:IsDefenseBelow(800)
end
function s.destg(e,tp,eg,ep,ev,re,r,rp,chk,chkc)
	if chkc then return chkc:IsLocation(LOCATION_MZONE) and s.dfilter(chkc) end
	if chk==0 then return Duel.IsExistingTarget(s.dfilter,tp,LOCATION_MZONE,LOCATION_MZONE,1,nil) end
	Duel.Hint(HINT_OPSELECTED,1-tp,e:GetDescription())
	Duel.Hint(HINT_SELECTMSG,tp,HINTMSG_DESTROY)
	local g=Duel.SelectTarget(tp,s.dfilter,tp,LOCATION_MZONE,LOCATION_MZONE,1,1,nil)
	Duel.SetOperationInfo(0,CATEGORY_DESTROY,g,1,0,0)
end
function s.desop(e,tp,eg,ep,ev,re,r,rp)
	local tc=Duel.GetFirstTarget()
	if tc and s.dfilter(tc) and tc:IsRelateToEffect(e) then
		Duel.Destroy(tc,REASON_EFFECT)
	end
end