-- app/Cache/Redis/Script/rate_limit.lua
local key = KEYS[1]
local limit = tonumber(ARGV[1])
local window = tonumber(ARGV[2])
local current = redis.call('GET', key)
local remaining = 0
if current then
    remaining = tonumber(current) - 1
    if remaining >= 0 then
        redis.call('DECR', key)
    else
        remaining = -1
    end
else
    remaining = limit - 1
    redis.call('SET', key, remaining, 'EX', window)
end
return {remaining >= 0, remaining}