// Shared dashboard render + format helpers.
//
// Small pure utilities used across most dashboard tabs (the container
// tree, the rebuild queue, questions / approvals, schedules + reminders):
// an atomic-swap render helper and a handful of relative-time / duration
// formatters. They live here — a dashboard-internal module — rather than
// in the cross-page `common.js`, because they're specific to the
// dashboard's render style and not needed by the stand-alone pages.
//
// All pure: no DOM/module state captured, so any tab module can import
// them freely without ordering concerns.

// Atomic-swap render: build into an off-DOM DocumentFragment, then commit
// with a single `replaceChildren`. Avoids an intermediate empty-state
// flash on poll cycles even when the builder allocates a lot of nodes.
export function paintAtomic(liveRoot, build) {
  const buf = document.createDocumentFragment();
  build(buf);
  liveRoot.replaceChildren(buf);
}

// Relative age of a unix timestamp, coarsened to one unit ("5m ago").
export function fmtAgo(unixSecs) {
  const ageSec = Math.max(0, Math.floor(Date.now() / 1000 - unixSecs));
  if (ageSec < 60) return ageSec + 's ago';
  if (ageSec < 3600) return Math.floor(ageSec / 60) + 'm ago';
  if (ageSec < 86400) return Math.floor(ageSec / 3600) + 'h ago';
  return Math.floor(ageSec / 86400) + 'd ago';
}

// Truncate a string to `n` chars, appending an ellipsis when clipped.
export function truncate(s, n) {
  return s.length <= n ? s : s.slice(0, n - 1) + '…';
}

// Running-duration label for in-flight items ("3m 12s running").
export function fmtElapsed(secs) {
  if (secs < 60) return secs + 's running';
  if (secs < 3600) return Math.floor(secs / 60) + 'm ' + (secs % 60) + 's running';
  return Math.floor(secs / 3600) + 'h ' + Math.floor((secs % 3600) / 60) + 'm running';
}

// Compact duration label, two units deep ("1h 5m", "2d 3h").
export function fmtDuration(secs) {
  if (secs < 60) return secs + 's';
  if (secs < 3600) return Math.floor(secs / 60) + 'm ' + (secs % 60) + 's';
  if (secs < 86400) return Math.floor(secs / 3600) + 'h ' + Math.floor((secs % 3600) / 60) + 'm';
  return Math.floor(secs / 86400) + 'd ' + Math.floor((secs % 86400) / 3600) + 'h';
}