export type UpdateState = {
  status: string; requestId?: string; command?: 'check' | 'apply'; phase?: string;
  version?: string; revision?: string; recoveryRequired?: boolean; updatedAt?: string;
}
export type UpdateJob = UpdateState & {
  progress?: UpdateState; error?: { code: string; message: string };
  plan?: { version: string; revision: string; previousVersion?: string; updateAvailable: boolean;
    requiresComposeAdoption: boolean; estimatedBackupBytes?: number; retiredServices: string[] };
}
export type UpdateLogs = { requestId: string; logs: { source: 'service' | 'events' | 'commands'; content: string; truncated: boolean }[] }
type Overview = {
  acceptingRequests: boolean; engine: UpdateState; request?: UpdateJob;
  installed: { version?: string }; backend: { version: string; revision: string };
  capabilities?: { requestLogs: boolean };
}
type Submission = { command: 'check' | 'apply'; body: { requestId: string; version?: string; checkRequestId?: string } }

export const useSelfhostUpdates = () => {
  const { $api } = useNuxtApp()
  const auth = useAuthStore()
  const overview = ref<Overview | null>(null)
  const job = ref<UpdateJob | null>(null)
  const pending = ref<Submission | null>(null)
  const connected = ref(false)
  const submitting = ref(false)
  const refreshing = ref(false)
  const message = ref('')
  const accessDenied = ref(false)
  const logs = ref<UpdateLogs | null>(null)
  const logsOpen = ref(false)
  const logsLoading = ref(false)
  const logsMessage = ref('')
  const logEntries = computed(() => logs.value?.requestId === job.value?.requestId ? logs.value?.logs || [] : [])
  let openedFailureId: string | undefined
  let stopped = false
  let generation = 0
  let timer: ReturnType<typeof setTimeout> | undefined
  const storageKey = `fedeo:update:${auth.user?.user_id || auth.user?.id || auth.user?.email}`
  const active = (value?: UpdateState | null) => ['queued', 'running'].includes(value?.status || '')
  const recovery = computed(() => !!overview.value?.engine.recoveryRequired && !active(overview.value?.engine))
  const busy = computed(() => submitting.value || !!pending.value || active(job.value) || active(overview.value?.engine))
  const available = computed(() => connected.value && !accessDenied.value && overview.value?.acceptingRequests && !busy.value && !recovery.value)
  const canApply = computed(() => !!(available.value && job.value?.command === 'check' && job.value.status === 'checked'
    && job.value.plan?.updateAvailable && !job.value.plan.requiresComposeAdoption))

  const persist = () => {
    // Losing localStorage must not lose the durable host job; status also returns the latest request.
    try { localStorage.setItem(storageKey, JSON.stringify({ requestId: job.value?.requestId, pending: pending.value })) } catch {}
  }
  const api = <T>(path: string, options = {}) => $api<T>(`/api/admin/updates/${path}`, {
    retry: 0, timeout: 8000, onRequestError: () => {}, onResponseError: () => {}, ...options,
  })
  const errorStatus = (error: any) => error?.statusCode || error?.response?.status
  const report = (error: any) => {
    if ([401, 403].includes(errorStatus(error))) {
      accessDenied.value = true
      message.value = 'Bitte erneut als Systemadministrator anmelden.'
    } else if (pending.value) {
      message.value = 'Der Start ist noch nicht bestätigt. Der Auftragsstatus wird weiter geprüft.'
    } else if (job.value?.command === 'apply' && active(job.value)) {
      message.value = 'Verbindung unterbrochen. Der Host führt das Update weiter aus; die Verbindung wird automatisch erneut geprüft.'
    } else {
      message.value = error?.data?.error?.message || 'Der Update-Dienst ist nicht erreichbar. Dienst und Socket-Einbindung auf dem Host prüfen.'
    }
  }
  const refreshLogs = async () => {
    const id = job.value?.requestId
    if (!logsOpen.value || !id || stopped || accessDenied.value || logsLoading.value) return
    if (logs.value?.requestId !== id) { logs.value = null; logsMessage.value = '' }
    if (!overview.value?.capabilities?.requestLogs) {
      logsMessage.value = 'Dieser Host-Update-Dienst unterstützt die Protokollansicht noch nicht. Die zusammengehörigen Host-Update-Dateien aktualisieren und den Dienstinstaller erneut ausführen. Bis dahin liegen die Protokolle auf dem Host unter .updates/.'
      return
    }
    const currentGeneration = generation
    logsLoading.value = true
    try {
      const result = await api<UpdateLogs>(`requests/${encodeURIComponent(id)}/logs`)
      if (stopped || currentGeneration !== generation || job.value?.requestId !== id) return
      logs.value = result
      logsMessage.value = ''
    } catch (error: any) {
      if (stopped || currentGeneration !== generation || job.value?.requestId !== id) return
      logsMessage.value = error?.data?.error?.message || 'Das Update-Protokoll konnte nicht geladen werden. Die Abfrage wird automatisch wiederholt.'
      if ([401, 403].includes(errorStatus(error))) { logs.value = null; report(error) }
    } finally { logsLoading.value = false }
  }
  const toggleLogs = async () => { logsOpen.value = !logsOpen.value; await refreshLogs() }
  const refresh = async () => {
    if (refreshing.value || stopped || accessDenied.value) return
    refreshing.value = true
    const currentGeneration = generation
    try {
      const latest = await api<Overview>('status')
      if (currentGeneration !== generation || stopped) return
      overview.value = latest
      // A durable submission may have succeeded even when its HTTP response was lost.
      const ownId = pending.value?.body.requestId || job.value?.requestId
      if (ownId) {
        try {
          const result = await api<UpdateJob>(`requests/${encodeURIComponent(ownId)}`)
          if (currentGeneration !== generation || stopped) return
          job.value = result
          pending.value = null
        } catch (error) {
          if (currentGeneration !== generation || stopped) return
          if (errorStatus(error) !== 404) throw error
          if (!pending.value) job.value = null
        }
      }
      if (!pending.value && latest.request && (active(latest.request) || !job.value)) job.value = latest.request
      connected.value = true
      message.value = pending.value ? 'Start noch nicht bestätigt. Du kannst denselben Auftrag erneut senden.' : ''
      persist()
      if (['failed', 'interrupted'].includes(job.value?.status || '') && openedFailureId !== job.value?.requestId) {
        openedFailureId = job.value?.requestId
        logsOpen.value = true
      }
      await refreshLogs()
    } catch (error) {
      if (currentGeneration !== generation || stopped) return
      connected.value = false
      report(error)
    } finally { refreshing.value = false }
  }
  const sendPending = async () => {
    if (!pending.value || submitting.value || accessDenied.value) return
    generation++
    logs.value = null
    logsMessage.value = ''
    submitting.value = true
    const submission = pending.value
    try {
      job.value = await api<UpdateJob>(submission.command, { method: 'POST', body: submission.body })
      pending.value = null
      connected.value = true
      message.value = ''
    } catch (error: any) {
      // Only a definite rejection releases the ID. Timeouts/5xx keep it for idempotent recovery.
      if ([400, 401, 403, 404, 409, 413, 415].includes(errorStatus(error))) {
        pending.value = null
        job.value = null
        message.value = error?.data?.error?.message || 'Der Auftrag wurde abgelehnt. Bitte erneut prüfen.'
        if ([401, 403].includes(errorStatus(error))) report(error)
      } else {
        connected.value = false
        report(error)
      }
    } finally { submitting.value = false; persist() }
    await refreshLogs()
  }
  const check = async () => {
    if (!available.value) return
    pending.value = { command: 'check', body: { requestId: crypto.randomUUID() } }
    job.value = null
    persist()
    await sendPending()
  }
  const apply = async () => {
    if (!canApply.value) return
    pending.value = { command: 'apply', body: {
      requestId: crypto.randomUUID(), version: job.value!.plan!.version, checkRequestId: job.value!.requestId!,
    } }
    persist()
    await sendPending()
  }
  const poll = async () => {
    await refresh()
    if (!stopped && !accessDenied.value) timer = setTimeout(poll, busy.value || !connected.value ? 3000 : 15000)
  }
  onMounted(() => {
    try {
      const saved = JSON.parse(localStorage.getItem(storageKey) || 'null')
      const validId = (value: unknown) => typeof value === 'string' && /^[A-Za-z0-9][A-Za-z0-9_-]{7,79}$/.test(value)
      if (validId(saved?.requestId)) job.value = { status: 'unknown', requestId: saved.requestId }
      const p = saved?.pending
      if (p && ['check', 'apply'].includes(p.command) && validId(p.body?.requestId)
        && (p.command === 'check' || (validId(p.body?.checkRequestId) && /^\d+\.\d+\.\d+$/.test(p.body?.version)))) {
        pending.value = { command: p.command, body: { requestId: p.body.requestId,
          ...(p.command === 'apply' ? { version: p.body.version, checkRequestId: p.body.checkRequestId } : {}) } }
      }
    } catch {}
    void poll()
  })
  onBeforeUnmount(() => { stopped = true; clearTimeout(timer) })
  return { overview, job, pending, connected, submitting, refreshing, message, accessDenied, recovery, busy, available, canApply,
    logsOpen, logsLoading, logsMessage, logEntries, refreshLogs, toggleLogs, check, apply, refresh, sendPending }
}