/**
 * Monotonic timing for spans (performance.now when available; else coarse wall fallback).
 */
export function bareOsMonotonicNowMs() {
  if (typeof globalThis.performance?.now === 'function') {
    return globalThis.performance.now()
  }
  return Date.now()
}

/**
 * @param {number} startMs
 */
export function bareOsMonotonicElapsedMs(startMs) {
  return Math.max(0, bareOsMonotonicNowMs() - startMs)
}

/**
 * High-resolution time for `/proc` hints: `process.hrtime.bigint` when available, else `performance.now`.
 */
export function bareOsHrtimeSnapshot() {
  try {
    const hr = globalThis.process?.hrtime?.bigint
    if (typeof hr === 'function') {
      const ns = hr.call(globalThis.process)
      return {
        schema: 1,
        source: 'process.hrtime.bigint',
        bigintNs: ns.toString(),
        atMs: Date.now()
      }
    }
  } catch {
    /* ignore */
  }
  return {
    schema: 1,
    source: 'performance.now',
    monotonicMs: bareOsMonotonicNowMs(),
    atMs: Date.now()
  }
}