// ── Team activity retention worker ──────────────────────────────────────────
//
// TEAMS.md §4.2's nightly prune: an age horizon (`team_activity_retain_days`,
// default 90) and a per-Team row cap (`team_activity_row_cap`, default 2000).
// Both live in `settings`, so an operator can tighten a busy shard without a
// deploy.
//
// Same in-process shape as utils/announceWorker and middleware/botScore's
// sweeper — setInterval + unref + stop(), wired into server.js start/shutdown.
// There is no cron in this stack and adding one for a single daily DELETE would
// be a dependency to justify at every future upgrade.
//
// **The first run is delayed rather than immediate.** A prune at boot would put a
// table-wide DELETE in front of the first request on every restart, and a
// deployment that is crash-looping would run it on every loop. Five minutes in is
// past the point where a boot has either succeeded or failed.

const teamActivity = require('../model/teams/teamActivity.model')
const log = require('./logger')('teams')

// Nightly, per §4.2. Not aligned to a wall-clock hour: the work is proportional
// to what arrived rather than to when it is done, and pinning it to 03:00 would
// mean a process that restarts each afternoon never prunes at all.
const INTERVAL_MS = Number(process.env.TEAM_ACTIVITY_PRUNE_MS) || 24 * 60 * 60 * 1000
const FIRST_RUN_MS = Number(process.env.TEAM_ACTIVITY_PRUNE_DELAY_MS) || 5 * 60 * 1000

let timer = null
let firstRun = null

/** One prune. Never throws — it runs on a timer with nobody to catch it. */
async function tick() {
  try {
    return await teamActivity.prune()
  } catch (err) {
    log.error('team activity prune failed', { message: err.message })
    return null
  }
}

function start() {
  if (timer || firstRun) return timer
  firstRun = setTimeout(() => {
    firstRun = null
    tick()
    timer = setInterval(() => { tick() }, INTERVAL_MS)
    if (timer.unref) timer.unref()
  }, FIRST_RUN_MS)
  if (firstRun.unref) firstRun.unref()
  log.info('team activity retention started', { intervalMs: INTERVAL_MS, firstRunMs: FIRST_RUN_MS })
  return timer
}

function stop() {
  if (firstRun) {
    clearTimeout(firstRun)
    firstRun = null
  }
  if (timer) {
    clearInterval(timer)
    timer = null
  }
}

module.exports = { start, stop, tick, INTERVAL_MS, FIRST_RUN_MS }