How many seconds until the next day with UTC. LUA

local utc = 2
local one_day = 86400 -- 60*60*24

local function set_hours(tbl_date, h, m, s)
   tbl_date.hour = h
   tbl_date.min  = m
   tbl_date.sec  = s
   return os.time(tbl_date)
end

local current_time = os.time() + (utc*60*60) -- Time with UTC
local current_day = os.date('*t', current_time)
local clear_date = set_hours(current_day, 0, 0, 0)
local next_day_date = clear_date + one_day
local sec_to_next_day = next_day_date - current_time

-- Test
print('UTC', utc)
print('Sec to next day', sec_to_next_day)
print('Today', os.date('%c', os.time(current_day)))
print('Next', os.date('%c', current_time + sec_to_next_day))