/**
 * Canonical booter boot-step identifiers emitted through {@link emitBooterBootStep}
 * (lifecycle / diagnostics). Keep in sync with `emitBooterBootPhase` call sites in `index.js`.
 */
export const BARE_OS_BOOTER_BOOT_STEPS = Object.freeze([
  'vfs',
  'ctx',
  'repl',
  'initd',
  'kernel_invoke'
])

/**
 * @param {string} step
 * @returns {boolean}
 */
export function isKnownBareOsBooterBootStep(step) {
  return BARE_OS_BOOTER_BOOT_STEPS.includes(String(step))
}

/**
 * @param {{
 *   bootReadyStateRef: { booterPhases: string[], booterStages: string[] },
 *   bootStartedMs: number,
 *   bootHrtimeNowNs?: (() => bigint) | null,
 *   bootEventSubs: Iterable<(ev: Record<string, unknown>) => unknown>,
 *   diagnosticsSubs: Iterable<(ev: Record<string, unknown>) => unknown>,
 *   sessionId: string,
 *   lifecycleSchemaVersion: string | number
 * }} deps
 */
export function createBooterBootEmitter(deps) {
  const {
    bootReadyStateRef,
    bootStartedMs,
    bootHrtimeNowNs = null,
    bootEventSubs,
    diagnosticsSubs,
    sessionId,
    lifecycleSchemaVersion
  } = deps

  function emitBooterBootStep(step) {
    const p = String(step)
    const arr = bootReadyStateRef.booterPhases
    const arrSt = bootReadyStateRef.booterStages
    if (!arr.includes(p)) arr.push(p)
    if (!arrSt.includes(p)) arrSt.push(p)
    const ev = {
      type: 'boot',
      phase: 'booter:' + p,
      ms: Date.now() - bootStartedMs,
      ts: Date.now(),
      sessionId,
      lifecycleSchemaVersion,
      ...(bootHrtimeNowNs ? { monotonicNs: String(bootHrtimeNowNs()) } : {})
    }
    for (const fn of bootEventSubs) {
      Promise.resolve(fn(ev)).catch(() => {})
    }
    for (const fn of diagnosticsSubs) {
      Promise.resolve(fn({ ...ev, source: 'booter' })).catch(() => {})
    }
  }

  function emitBooterBootPhase(phase) {
    return emitBooterBootStep(phase)
  }

  return { emitBooterBootStep, emitBooterBootPhase }
}