Here you go
RegisterCommand("armas", function(source, args, raw)
local weapons = {pistol = "WEAPON_PISTOL", smg = "WEAPON_SMG"}
local ped = GetPlayerPed(-1)
local selectedWeapon = weapons["pistol"] -- Default Weapon
local selectedAmmo = 60 -- Default Ammo
-- Player Selected Weapon
local chosenWeapon = nil
if args[1] ~= nil then chosenWeapon = tostring(string.lower(args[1])) end
-- Player Selected Ammo
local chosenAmmo = nil
if args[2] ~= nil ~= nil then chosenAmmo = tonumber(args[2]) end
if chosenWeapon ~= nil then if weapons[chosenWeapon] ~= nil then selectedWeapon = weapons[chosenWeapon] end end
if chosenAmmo ~= nil then selectedAmmo = chosenAmmo end
GiveWeaponToPed(ped, GetHashKey(selectedWeapon), selectedAmmo, true, true)
end, false)