/**
 * Simple per-peer sliding window rate limiter.
 */

const WINDOW_MS = 60_000
const DEFAULT_RPM = Number(process.env.PEARDATA_RATE_LIMIT_RPM) || 120

/** @type {Map<string, number[]>} */
const hits = new Map()

const STREAM_METHODS = new Set([
  'ping',
  'queryData',
  'subscribeMetrics',
  'unsubscribeMetrics',
  'getAllMetrics',
])

/**
 * @param {{ id: string }} session
 * @param {string} method
 */
export function isAllowed(session, method) {
  if (STREAM_METHODS.has(method)) return true
  const id = session?.id || 'anon'
  const now = Date.now()
  let list = hits.get(id)
  if (!list) {
    list = []
    hits.set(id, list)
  }
  const cutoff = now - WINDOW_MS
  while (list.length && list[0] < cutoff) list.shift()
  if (list.length >= DEFAULT_RPM) return false
  list.push(now)
  return true
}

export function isStreamMethod(method) {
  return STREAM_METHODS.has(method)
}

export default { isAllowed, isStreamMethod }