// A vendored copy of the one helper this module uses from core's
// `client/src/lib/format.js`.
//
// **Vendored rather than added to the kit, and trimmed rather than copied
// whole.** The kit is curated and closed (MODULE_API.md §3.4): every member
// added to it is a minor version bump core can never take back, and a date
// formatter is not the kind of thing a module should be unable to write. Copying
// all six of core's helpers to get one would leave five with no consumer here
// and a standing question about which copy is authoritative.
//
// The vendoring line, from the server half of the extraction (slice 1): **pure
// leaf helpers may be copied, security controls may not.** This is a pure leaf.
// Core's HTML sanitiser sits two files away and stays exactly where it is.
//
// The two copies will drift, and that is correct — core's is core's to change.
// Nothing here reads a shared format.

function parse(value) {
  if (!value) return null
  const d = new Date(value)
  return isNaN(d.getTime()) ? null : d
}

/** "3m ago". Coarse on purpose: the live feed's timestamps are approximate. */
export function ago(value) {
  const d = parse(value)
  if (!d) return ''
  const secs = Math.max(1, Math.floor((Date.now() - d.getTime()) / 1000))
  if (secs < 60) return `${secs}s ago`
  const mins = Math.floor(secs / 60)
  if (mins < 60) return `${mins}m ago`
  const hrs = Math.floor(mins / 60)
  if (hrs < 24) return `${hrs}h ago`
  const days = Math.floor(hrs / 24)
  return `${days}d ago`
}