-- HYPOTHETICAL Redis 7.4 materialized feature snapshot.
-- One key; version is fixed-width 20-digit monotonic sequence PER KEY.
-- ARGV: version, JSON payload, absolute expiry Unix milliseconds.
if #KEYS ~= 1 or #ARGV ~= 3 then return redis.error_reply('arguments') end
local version = ARGV[1]
local expiry = tonumber(ARGV[3])
if #version ~= 20 or not string.match(version,'^%d+$')
 or not expiry or expiry < 1 or expiry > 9007199254740991
 or expiry ~= math.floor(expiry) then return redis.error_reply('invalid arguments') end
local kind = redis.call('TYPE',KEYS[1])
if type(kind) == 'table' then kind = kind.ok end
if kind ~= 'none' and kind ~= 'hash' then return redis.error_reply('wrong key type') end
local t = redis.call('TIME')
local now = tonumber(t[1])*1000 + math.floor(tonumber(t[2])/1000)
if expiry <= now then return 0 end
local old = redis.call('HGET',KEYS[1],'version')
if old and version <= old then return 0 end
redis.call('HSET',KEYS[1],'version',version,'payload',ARGV[2])
redis.call('PEXPIREAT',KEYS[1],expiry)
return 1
-- No retained version after key expiry: a late older but unexpired snapshot could
-- reappear. Upstream must enforce ordered per-key versioned snapshots and drop
-- obsolete event-time windows; rebuild/switch generations after state loss.