// @local/dsh-remote — Host side.
//
// Master/slave remote control for DSH (Claude-Desktop-remote style):
//   * slaves keep one authenticated WebSocket link to the master (outbound, NAT-friendly);
//   * every device's DSH is reachable from every other device at /r/<device>/ (HTTP +
//     WebSocket tunnelled over the link; sessions execute on the owning machine);
//     slave→slave goes through the master's relay;
//   * the master aggregates device + session lists for the Devices UI;
//   * plugins and config are synced master → slave (managed bundle layer, allow/deny,
//     opt-in per-secret credential sync).
//
// HTTP routes (all behind DSH's own browser auth via ctx.connection.requestRejection):
//   GET  /dsh-remote/state                → role, self, link status, devices (+ online)
//   GET  /dsh-remote/sessions             → sessions of every reachable device
//   POST /dsh-remote/pairing              → master: create a one-time pairing code
//   POST /dsh-remote/pair                 → slave: pair with {masterUrl, code}
//   POST /dsh-remote/unpair               → slave: forget the master
//   POST /dsh-remote/devices/<id>/revoke  → master: revoke a device key
//   POST /dsh-remote/devices/<id>/remove  → master: delete a device
//   POST /dsh-remote/devices/<id>/sync    → master: set {enabled, allow, deny, secrets}
//   POST /dsh-remote/sync                 → slave: pull + apply now
//   GET  /dsh-remote/sync/status          → slave: last sync result / master: manifest summary
//   POST /dsh-remote/new-session          → {device, cwd?} create a session on a device
//   *    /r/<device>/...                  → proxy to that device's DSH
// Upgrade routes:
//   /dsh-remote/link                      → slave → master link (device id + key headers)
//   /r/<device>/api/remote.mux            → DSH Remote stream WebSocket of another device
import os from 'node:os'
import { acceptUpgrade, connect, rejectUpgrade } from './lib/ws.mjs'
import { Mux } from './lib/mux.mjs'
import { Store, randomId, setProfileDir, slug } from './lib/store.mjs'
import { CookieJar } from './lib/auth-cookie.mjs'
import { ownHttp, ownUpgrade, viewHttp, viewUpgrade } from './lib/proxy.mjs'
import * as sync from './lib/sync.mjs'
import * as ops from './lib/agent-ops.mjs'

export const name = 'dsh-remote'
export const inject = {
  webServer: { required: true },
  connection: { required: true },
  credentials: { required: false },
  tools: { required: false },
}

/** Optional services, read at call time (they may load after this plugin). */
function svc(ctx, key) {
  try { return ctx.get(key) } catch { return undefined }
}

const MAX_BODY = 256 * 1024
const PREFIX = '/r/'
const LINK_PATH = '/dsh-remote/link'
const MUX_PATH = '/api/remote.mux'
/** Link methods that act on a device on behalf of an agent. */
const OPS = new Set(['exec', 'readFile', 'writeFile', 'listDir', 'task', 'taskStatus', 'taskCancel', 'inspectSession'])
/** Pseudo-secret name: opting into it ships the master's forge (git) logins. */
const FORGE_SECRET = 'FORGE_CREDENTIALS'

function sendJson(res, status, payload) {
  res.statusCode = status
  res.setHeader('content-type', 'application/json; charset=utf-8')
  res.setHeader('cache-control', 'no-store')
  res.end(JSON.stringify(payload))
}

async function readJson(req) {
  const chunks = []
  let size = 0
  for await (const c of req) {
    size += c.length
    if (size > MAX_BODY) throw Object.assign(new Error('body too large'), { status: 413 })
    chunks.push(c)
  }
  if (!size) return {}
  const v = JSON.parse(Buffer.concat(chunks).toString('utf8'))
  if (!v || typeof v !== 'object' || Array.isArray(v)) throw Object.assign(new Error('body must be an object'), { status: 400 })
  return v
}

const httpErr = (status, message) => Object.assign(new Error(message), { status })

export function apply(ctx, config = {}) {
  const prof = svc(ctx, 'profileContext')
  if (prof?.dir) setProfileDir(prof.dir)
  const store = new Store()
  const self = store.identity(config.deviceName || os.hostname())
  if (config.deviceName && config.deviceName !== self.name) {
    self.name = config.deviceName
    store.save()
  }
  const role = config.role === 'master' ? 'master' : config.role === 'slave' ? 'slave' : (store.master ? 'slave' : 'master')
  const log = ctx.logger ?? console
  const cookies = new CookieJar(ctx)
  const localTarget = () => ({ host: '127.0.0.1', port: ctx.webServer.port })

  // device id -> { mux, info, connectedAt }   (master: slaves; slave: { master })
  const links = new Map()
  const listeners = new Set()
  const notify = (event) => { for (const l of listeners) { try { l(event) } catch { /* ignore */ } } }
  let lastSync = store.data.lastSync || null
  let masterLink = null // slave only

  // ------------------------------------------------------------------ stream routing
  // A stream's meta.to names the device that must serve it. "self" streams hit local DSH.
  // The master relays streams whose target is another slave.
  function serveStream(stream) {
    const to = stream.meta.to
    if (to && to !== self.id) {
      if (role !== 'master') return stream.fail(`cannot relay to ${to}`)
      const peer = links.get(to)
      if (!peer) return stream.fail(`device ${to} offline`)
      return relay(stream, peer.mux)
    }
    if (stream.kind === 'http') return ownHttp(stream, { target: localTarget(), cookie: (a) => cookies.get(a) })
    if (stream.kind === 'ws') return ownUpgrade(stream, { target: localTarget(), cookie: (a) => cookies.get(a) })
    if (stream.kind === 'blob') return serveBlob(stream)
    return stream.fail(`unknown stream kind ${stream.kind}`)
  }

  /** Splice an incoming stream onto a new stream to another link (master relay). */
  function relay(inbound, mux) {
    const out = mux.open(inbound.kind, inbound.meta)
    const pipe = (a, b) => {
      a.on('head', (m) => b.head(m))
      a.on('data', (d) => b.write(d))
      a.on('end', () => b.end())
      a.on('error', (e) => b.fail(e.message))
      a.on('remote-pause', () => b.mux.sendControl({ t: 'pause', id: b.id }))
      a.on('remote-resume', () => b.mux.sendControl({ t: 'resume', id: b.id }))
    }
    pipe(inbound, out)
    pipe(out, inbound)
    inbound.start()
  }

  // ------------------------------------------------------------------ control handlers
  const handlers = {
    hello: async (p) => ({ id: self.id, name: self.name, role, version: config.version || '1' }),
    sessions: async () => listLocalSessions(),
    newSession: async (p) => createLocalSession(p),
    devices: async (p, mux) => devicesView(),
    route: async () => ({ ok: true }),
    manifest: async (p, mux) => {
      if (role !== 'master') throw httpErr(400, 'not a master')
      const dev = store.devices()[mux.deviceId]
      if (dev?.sync?.enabled === false) return { version: 1, bundles: [], patch: [], secrets: [], disabled: true }
      const m = await buildManifestCached()
      return { ...m, _dirs: undefined, secrets: offerSecretsFor(dev) }
    },
    secret: async (p, mux) => {
      if (role !== 'master') throw httpErr(400, 'not a master')
      const dev = store.devices()[mux.deviceId]
      const name = String(p.name || '')
      if (!offerSecretsFor(dev).includes(name)) throw httpErr(403, `secret ${name} not offered to this device`)
      const c = svc(ctx, 'credentials')
      if (!c) throw httpErr(503, 'credentials service unavailable')
      const r = await c.resolve(name)
      if (!r?.value) throw httpErr(404, `secret ${name} not set on master`)
      return { name, value: r.value }
    },
    // Forwarded calls: master answers for another device by asking it.
    forward: async (p, mux) => {
      if (role !== 'master') throw httpErr(400, 'not a master')
      const peer = links.get(p.device)
      if (!peer) throw httpErr(404, `device ${p.device} offline`)
      // Agent control (exec/files/task) is master → device only, unless explicitly allowed.
      if (OPS.has(p.method) && config.agentTools?.allowPeerControl !== true) throw httpErr(403, `${p.method} on other devices is only allowed from the master`)
      return peer.mux.call(p.method, p.params || {}, p.timeoutMs || 20000)
    },
    // ---- agent operations (served by the target device) ----
    exec: async (p, mux) => { guardOps(mux); return ops.execCommand(p) },
    readFile: async (p, mux) => { guardOps(mux); return ops.readFileOp(p) },
    writeFile: async (p, mux) => { guardOps(mux); return ops.writeFileOp(p) },
    listDir: async (p, mux) => { guardOps(mux); return ops.listDirOp(p) },
    task: async (p, mux) => { guardOps(mux); return ops.runTask(svc(ctx, 'sessionController'), svc(ctx, 'workspaceRegistry'), p, undefined, svc(ctx, 'permissionPresets')) },
    taskStatus: async (p, mux) => { guardOps(mux); return ops.taskStatus(svc(ctx, 'sessionController'), p) },
    taskCancel: async (p, mux) => { guardOps(mux); return svc(ctx, 'sessionController').cancel({ sessionId: p.sessionId }) },
    inspectSession: async (p, mux) => {
      guardOps(mux)
      const ins = await svc(ctx, 'sessionController').inspect(p.sessionId)
      return { sessionId: p.sessionId, events: ins.events.slice(-Math.min(Number(p.last) || 400, 2000)) }
    },
    // Master → slave: hand over forge logins (only names the slave accepted).
    forgeLogins: async (p, mux) => {
      if (role !== 'master') throw httpErr(400, 'not a master')
      const dev = store.devices()[mux.deviceId]
      if (!offerSecretsFor(dev).includes(FORGE_SECRET)) throw httpErr(403, `${FORGE_SECRET} not offered to this device`)
      return { logins: ops.readForgeLogins() }
    },
  }

  /**
   * Agent ops arrive over a link. On a slave, only the master may call them; on the master,
   * slaves may not (the master is the controller) unless allowPeerControl is set.
   */
  function guardOps(mux) {
    if (config.agentTools?.enabled === false) throw httpErr(403, `agent control is disabled on ${self.name}`)
    if (role === 'slave' && mux?.deviceId !== 'master') throw httpErr(403, 'agent control only from the master')
    if (role === 'master' && mux && config.agentTools?.allowPeerControl !== true) throw httpErr(403, 'slaves may not control the master')
  }

  function offerSecretsFor(dev) {
    const offered = new Set(config.sync?.offerSecrets || [])
    return (dev?.sync?.secrets || []).filter((n) => offered.has(n))
  }

  let manifestCache = null
  async function buildManifestCached() {
    if (manifestCache && Date.now() - manifestCache.at < 15000) return manifestCache.value
    const value = await sync.buildManifest({
      self,
      include: config.sync || {},
      offerSecrets: config.sync?.offerSecrets || [],
    })
    manifestCache = { at: Date.now(), value }
    return value
  }

  async function serveBlob(stream) {
    // Only the master serves blobs: packed local plugins named in its manifest.
    try {
      if (role !== 'master') throw new Error('not a master')
      const m = await buildManifestCached()
      const dir = m._dirs?.[stream.meta.name]
      if (!dir) throw new Error(`no local plugin ${stream.meta.name}`)
      const dev = store.devices()[stream.mux.deviceId]
      if (dev && !sync.allowed(stream.meta.name, dev.sync || {})) throw new Error('denied for this device')
      const buf = await sync.packLocal(dir)
      stream.head({ status: 200, size: buf.length })
      stream.write(buf)
      stream.end()
    } catch (e) {
      stream.fail(e.message)
    }
  }

  // ------------------------------------------------------------------ sessions
  async function listLocalSessions() {
    const sc = svc(ctx, 'sessionController')
    if (!sc) return { items: [], workspaces: [] }
    const ac = new AbortController()
    const t = setTimeout(() => ac.abort(), 10000)
    try {
      const { items } = await sc.list({}, ac.signal)
      const wr = svc(ctx, 'workspaceRegistry')
      const workspaces = wr ? wr.list().map((w) => ({ id: w.id, title: w.title, path: w.path })) : []
      return {
        items: items
          .filter((s) => !s.parentSessionId && !s.blank)
          .slice(0, config.maxSessions || 200)
          .map((s) => ({
            sessionId: s.sessionId,
            updatedAt: s.updatedAt,
            running: s.running,
            cwd: s.cwd,
            title: s.projections?.values?.title ?? null,
          })),
        workspaces,
      }
    } finally {
      clearTimeout(t)
    }
  }

  async function createLocalSession({ cwd, workspaceId } = {}) {
    const sc = svc(ctx, 'sessionController')
    if (!sc) throw httpErr(503, 'session controller unavailable')
    const req = {}
    if (workspaceId) req.workspaceId = workspaceId
    else if (cwd) req.cwd = cwd
    const r = await sc.create(req)
    return { sessionId: r.sessionId }
  }

  // ------------------------------------------------------------------ device views
  function devicesView() {
    const out = [{ id: self.id, name: self.name, role, self: true, online: true }]
    if (role === 'master') {
      for (const d of Object.values(store.devices())) {
        const l = links.get(d.id)
        out.push({
          id: d.id, name: d.name, platform: d.platform, role: 'slave', revoked: !!d.revoked,
          online: !!l, connectedAt: l?.connectedAt || null, lastSeenAt: d.lastSeenAt || null,
          sync: d.sync,
        })
      }
    } else if (masterLink?.info) {
      out.push({ ...masterLink.info, role: 'master', online: true })
      // Peers in the master's broadcast are by definition online right now.
      for (const d of masterLink.peers || []) if (d.id !== self.id && d.role !== 'master') out.push({ ...d, online: true, via: 'master' })
    }
    return out
  }

  /** Mux that reaches `device` from here (null = local). */
  function routeTo(device) {
    if (!device || device === self.id) return { local: true }
    if (role === 'master') {
      const l = links.get(device)
      return l ? { mux: l.mux, meta: {} } : null
    }
    if (!masterLink?.mux || masterLink.mux.closed) return null
    if (masterLink.info?.id === device) return { mux: masterLink.mux, meta: {} }
    return { mux: masterLink.mux, meta: { to: device } } // relay through master
  }

  async function callDevice(device, method, params, timeoutMs = 20000) {
    const r = routeTo(device)
    if (!r) throw httpErr(404, `device ${device} unreachable`)
    if (r.local) return handlers[method](params || {})
    if (r.meta.to) return r.mux.call('forward', { device, method, params, timeoutMs }, timeoutMs + 5000)
    return r.mux.call(method, params || {}, timeoutMs)
  }

  /** Resolve a device by id or (case-insensitive) name; "self"/"local" = this device. */
  function resolveDevice(ref) {
    const want = String(ref || '').trim().toLowerCase()
    if (!want || want === 'self' || want === 'local' || want === 'this') return self.id
    const all = devicesView()
    const hit = all.find((d) => d.id === want) || all.find((d) => String(d.name).toLowerCase() === want) || all.find((d) => slug(d.name) === slug(want))
    if (!hit) throw httpErr(404, `unknown device "${ref}". Known: ${all.map((d) => `${d.id}${d.online ? '' : ' (offline)'}`).join(', ')}`)
    if (!hit.online) throw httpErr(503, `device ${hit.id} is offline`)
    return hit.id
  }

  async function allSessions() {
    const devices = devicesView().filter((d) => d.online && !d.revoked)
    const results = await Promise.allSettled(devices.map(async (d) => ({ device: d, ...(await callDevice(d.id, 'sessions', {})) })))
    return results.map((r, i) => r.status === 'fulfilled'
      ? { device: devices[i].id, name: devices[i].name, self: !!devices[i].self, items: r.value.items, workspaces: r.value.workspaces }
      : { device: devices[i].id, name: devices[i].name, self: !!devices[i].self, error: String(r.reason?.message ?? r.reason), items: [] })
  }

  // ------------------------------------------------------------------ session activity watch
  // Poll local running states; emit "finished" events (for notifications) to all viewers.
  const lastRunning = new Map()
  async function pollActivity() {
    try {
      const { items } = await listLocalSessions()
      for (const s of items) {
        const was = lastRunning.get(s.sessionId)
        if (was === true && !s.running) {
          const ev = { type: 'session-finished', device: self.id, deviceName: self.name, sessionId: s.sessionId, title: s.title, at: Date.now() }
          notify(ev)
          broadcast('activity', ev)
        }
        lastRunning.set(s.sessionId, s.running)
      }
    } catch { /* ignore */ }
  }
  const activityTimer = setInterval(pollActivity, config.activityPollMs || 4000)
  activityTimer.unref?.()
  ctx.effect(() => () => clearInterval(activityTimer), 'dsh-remote: activity poll')

  function broadcast(name, data) {
    if (role === 'master') for (const l of links.values()) l.mux.event(name, data)
    else masterLink?.mux?.event(name, data)
  }

  function onLinkEvent(name, data, fromDevice) {
    if (name === 'activity') {
      notify(data)
      // Master fans slave activity out to the other slaves.
      if (role === 'master') for (const [id, l] of links) if (id !== fromDevice) l.mux.event(name, data)
    } else if (name === 'peers' && role === 'slave' && masterLink) {
      masterLink.peers = data
      notify({ type: 'devices' })
    } else if (name === 'sync-available' && role === 'slave') {
      if (config.sync?.auto !== false) runSlaveSync().catch((e) => log.warn(`dsh-remote: sync failed: ${e.message}`))
    }
  }

  function pushPeers() {
    if (role !== 'master') return
    const peers = devicesView().filter((d) => d.online).map(({ id, name, role: r, platform }) => ({ id, name, role: r, platform }))
    for (const l of links.values()) l.mux.event('peers', peers)
    notify({ type: 'devices' })
  }

  // ------------------------------------------------------------------ master: accept links
  if (role === 'master') {
    ctx.effect(() => ctx.webServer.registerUpgrade({
      path: LINK_PATH,
      handler: (req, socket, head) => {
        const id = String(req.headers['x-dsh-remote-device'] || '')
        const key = String(req.headers['x-dsh-remote-key'] || '')
        const dev = store.verifyDevice(id, key)
        if (!dev) return rejectUpgrade(socket, 401, 'unknown or revoked device')
        const ws = acceptUpgrade(req, socket, head)
        if (!ws) return
        const prev = links.get(id)
        if (prev) prev.mux.close(4000, 'replaced by new connection')
        const mux = new Mux(ws, { odd: false, handlers, onStream: serveStream })
        mux.deviceId = id
        const entry = { mux, connectedAt: Date.now(), info: { id, name: dev.name } }
        links.set(id, entry)
        dev.lastSeenAt = Date.now()
        dev.platform = String(req.headers['x-dsh-remote-platform'] || dev.platform || '')
        store.save()
        mux.on('event', (n, d) => onLinkEvent(n, d, id))
        mux.on('close', () => {
          if (links.get(id) === entry) links.delete(id)
          const d = store.devices()[id]
          if (d) { d.lastSeenAt = Date.now(); store.save() }
          log.info?.(`dsh-remote: ${id} disconnected`)
          pushPeers()
        })
        log.info?.(`dsh-remote: ${id} connected`)
        pushPeers()
      },
    }), 'dsh-remote: link endpoint')
  }

  // ------------------------------------------------------------------ slave: keep link up
  let stopped = false
  let backoff = 1000
  async function connectMaster() {
    const m = store.master
    if (!m || stopped) return
    const url = new URL(m.url)
    url.protocol = url.protocol === 'https:' ? 'wss:' : url.protocol === 'http:' ? 'ws:' : url.protocol
    url.pathname = url.pathname.replace(/\/+$/, '') + LINK_PATH
    try {
      const ws = await connect(url.href, {
        headers: {
          'x-dsh-remote-device': m.deviceId,
          'x-dsh-remote-key': m.key,
          'x-dsh-remote-platform': `${process.platform}-${process.arch}`,
        },
      })
      const mux = new Mux(ws, { odd: true, handlers, onStream: serveStream })
      mux.deviceId = 'master'
      masterLink = { mux, info: null, peers: [] }
      backoff = 1000
      mux.on('event', (n, d) => onLinkEvent(n, d, 'master'))
      mux.on('close', (code, reason) => {
        masterLink = null
        notify({ type: 'devices' })
        if (code === 4401) {
          lastLinkError = `master rejected this device (${reason || 'revoked'}); re-pair it`
          log.warn(`dsh-remote: ${lastLinkError}`)
          return
        }
        lastLinkError = `link closed (${code}${reason ? ' ' + reason : ''}); reconnecting`
        if (!stopped) schedule()
      })
      const info = await mux.call('hello', { id: self.id, name: self.name })
      masterLink.info = { id: info.id, name: info.name }
      // Only devices that are online on the master are reachable through its relay.
      masterLink.peers = (await mux.call('devices', {})).filter((d) => d.online && !d.revoked).map(({ id, name, role: r }) => ({ id, name, role: r }))
      notify({ type: 'devices' })
      lastLinkError = null
      log.info?.(`dsh-remote: linked to master ${info.name} (${m.url})`)
      if (config.sync?.auto !== false) runSlaveSync().catch((e) => log.warn(`dsh-remote: sync failed: ${e.message}`))
    } catch (e) {
      masterLink = null
      if (e.status === 401) { log.warn(`dsh-remote: master refused key (${e.message}); re-pair this device`); lastLinkError = e.message; return }
      lastLinkError = e.message
      schedule()
    }
  }
  let lastLinkError = null
  let timer = null
  function schedule() {
    clearTimeout(timer)
    timer = setTimeout(connectMaster, backoff)
    timer.unref?.()
    backoff = Math.min(backoff * 2, 30000)
  }
  if (role === 'slave') connectMaster()
  ctx.effect(() => () => {
    stopped = true
    clearTimeout(timer)
    masterLink?.mux?.close(1001, 'shutdown')
    for (const l of links.values()) l.mux.close(1001, 'shutdown')
  }, 'dsh-remote: links')

  // ------------------------------------------------------------------ slave: sync
  let syncing = null
  async function runSlaveSync() {
    if (role !== 'slave') throw httpErr(400, 'only slaves sync')
    if (syncing) return syncing
    syncing = (async () => {
      const mux = masterLink?.mux
      if (!mux) throw httpErr(503, 'not linked to a master')
      const local = config.sync || {}
      const manifest = await mux.call('manifest', {}, 30000)
      const result = { at: Date.now(), installed: [], updated: [], skipped: [], failed: [], secrets: [], patchEntries: manifest.patch?.length || 0 }
      if (manifest.disabled) { result.skipped.push('sync disabled for this device on master'); return result }
      const pm = svc(ctx, 'pluginManager')
      const prev = store.data.synced || {}
      const next = {}
      let profileChanged = false
      for (const b of manifest.bundles || []) {
        if (!sync.allowed(b.name, local)) { result.skipped.push(`${b.name} (local deny/allow)`); continue }
        try {
          if (b.kind === 'local') {
            if (prev[b.name]?.hash === b.hash) { next[b.name] = prev[b.name]; continue }
            const stream = mux.open('blob', { name: b.name })
            const buf = await new Promise((resolve, reject) => {
              const parts = []
              stream.on('data', (d) => parts.push(d))
              stream.on('end', () => { resolve(Buffer.concat(parts)); stream.end() })
              stream.on('error', reject)
            })
            const dir = await sync.unpackLocal(b.name, b.version, buf)
            profileChanged = sync.linkLocalBundle(b.name, dir) || profileChanged
            next[b.name] = { kind: 'local', hash: b.hash, version: b.version, dir }
            ;(prev[b.name] ? result.updated : result.installed).push(`${b.name}@${b.version}`)
          } else {
            if (!pm) throw new Error('plugin manager unavailable')
            const have = (await pm.listBundles()).find((x) => x.name === b.name)
            if (have?.installed && have.version === b.version) {
              if (!have.enabled) await pm.setBundleEnabled(b.name, true)
              next[b.name] = { kind: 'registry', version: b.version }
              continue
            }
            const r = await pm.installBundle(`${b.name}@${b.version}`, { enabled: true })
            if (r.application === 'failed') throw new Error(r.error?.message || 'install failed')
            next[b.name] = { kind: 'registry', version: b.version }
            ;(have ? result.updated : result.installed).push(`${b.name}@${b.version}`)
          }
        } catch (e) {
          result.failed.push(`${b.name}: ${e.message}`)
          if (prev[b.name]) next[b.name] = prev[b.name]
        }
      }
      // Config layer.
      await sync.writeManagedBundle(manifest.patch || [], Object.keys(next))
      profileChanged = sync.ensureManagedBundleOrder() || profileChanged
      // Opt-in secrets.
      for (const name of manifest.secrets || []) {
        if (!(local.secrets || []).includes(name)) continue
        try {
          if (name === FORGE_SECRET) {
            // Not a credential ref: the master's forge logins (tea + git https credentials).
            const { logins } = await mux.call('forgeLogins', {}, 15000)
            if (!logins?.length) throw new Error('master has no forge logins')
            const r = await ops.installForgeLogins(logins)
            result.secrets.push(`${name} (${r.installed.join(', ')})`)
            continue
          }
          const { value } = await mux.call('secret', { name }, 15000)
          const creds = svc(ctx, 'credentials')
          if (!creds) throw new Error('credentials service unavailable')
          await creds.set(name, value)
          result.secrets.push(name)
        } catch (e) {
          result.failed.push(`secret ${name}: ${e.message}`)
        }
      }
      store.data.synced = next
      store.data.lastSync = result
      store.save()
      lastSync = result
      result.restartRequired = profileChanged
      notify({ type: 'sync', result })
      // Unattended slaves (LaunchAgent KeepAlive / systemd Restart=always): restart DSH so
      // newly synced plugins load. Only when no session is running, and at most once per
      // 10 minutes so a broken plugin can't cause a restart loop.
      if (profileChanged && config.sync?.restartOnSync) scheduleSelfRestart('plugins changed by sync')
      return result
    })()
    try { return await syncing } finally { syncing = null }
  }

  function scheduleSelfRestart(reason) {
    const last = Number(store.data.lastSelfRestart || 0)
    if (Date.now() - last < 10 * 60 * 1000) { log.warn(`dsh-remote: restart needed (${reason}) but skipped: restarted <10 min ago`); return }
    const attempt = async (tries) => {
      let busy = false
      try { busy = (await listLocalSessions()).items.some((s) => s.running) } catch { busy = false }
      if (busy && tries < 60) { setTimeout(() => attempt(tries + 1), 30000).unref?.(); return }
      store.data.lastSelfRestart = Date.now()
      store.save()
      log.warn(`dsh-remote: restarting DSH (${reason}); the service manager brings it back`)
      setTimeout(() => process.kill(process.pid, 'SIGTERM'), 1500).unref?.()
    }
    setTimeout(() => attempt(0), 3000).unref?.()
  }

  // ------------------------------------------------------------------ HTTP API
  const route = (path, methods, handler) => ctx.effect(() => ctx.webServer.register({
    kind: 'exact',
    path,
    handler: async (req, res) => {
      const rejection = ctx.connection.requestRejection(req)
      if (rejection !== undefined) return sendJson(res, rejection, { error: 'rejected' })
      if (!methods.includes(req.method)) { res.statusCode = 405; res.setHeader('allow', methods.join(', ')); return res.end() }
      try {
        sendJson(res, 200, await handler(req, new URL(req.url || '/', 'http://x')))
      } catch (e) {
        sendJson(res, e.status && e.status < 600 ? e.status : 500, { error: String(e.message || e) })
      }
    },
  }), `dsh-remote: ${path}`)

  route('/dsh-remote/state', ['GET'], async () => ({
    role,
    self,
    master: role === 'slave' ? { url: store.master?.url || null, linked: !!masterLink?.mux, info: masterLink?.info || null, error: masterLink ? null : lastLinkError } : null,
    devices: devicesView(),
    publicUrl: config.publicUrl || null,
    lanUrl: config.lanUrl || null,
    lastSync,
    sync: { auto: config.sync?.auto !== false, allow: config.sync?.allow || [], deny: config.sync?.deny || [], secrets: config.sync?.secrets || [], offerSecrets: config.sync?.offerSecrets || [] },
  }))

  route('/dsh-remote/sessions', ['GET'], async () => ({ devices: await allSessions() }))

  route('/dsh-remote/pairing', ['POST'], async (req) => {
    if (role !== 'master') throw httpErr(400, 'pairing codes are created on the master')
    const body = await readJson(req)
    return store.createPairingCode({ label: String(body.label || '') })
  })

  // Pair endpoint ON THE MASTER, called by a slave's DSH (not by a browser): exchanges a
  // pairing code for a device key. Not behind browser auth (the code is the credential).
  ctx.effect(() => ctx.webServer.register({
    kind: 'exact',
    path: '/dsh-remote/enroll',
    handler: async (req, res) => {
      if (req.method !== 'POST') { res.statusCode = 405; return res.end() }
      try {
        if (role !== 'master') throw httpErr(400, 'not a master')
        const body = await readJson(req)
        const rec = store.consumePairingCode(body.code)
        if (!rec) throw httpErr(403, 'invalid or expired pairing code')
        const dev = store.addDevice({ id: body.id, name: body.name, platform: body.platform })
        sendJson(res, 200, { deviceId: dev.id, key: dev.secret, master: { id: self.id, name: self.name } })
      } catch (e) {
        sendJson(res, e.status || 500, { error: String(e.message || e) })
      }
    },
  }), 'dsh-remote: enroll')

  route('/dsh-remote/pair', ['POST'], async (req) => {
    const body = await readJson(req)
    const masterUrl = String(body.masterUrl || '').trim().replace(/\/+$/, '')
    if (!/^https?:\/\//.test(masterUrl)) throw httpErr(400, 'masterUrl must start with http:// or https://')
    const r = await fetch(`${masterUrl}/dsh-remote/enroll`, {
      method: 'POST',
      headers: { 'content-type': 'application/json' },
      body: JSON.stringify({ code: body.code, id: self.id, name: self.name, platform: `${process.platform}-${process.arch}` }),
    })
    const j = await r.json().catch(() => ({}))
    if (!r.ok) throw httpErr(r.status, j.error || `enroll failed (HTTP ${r.status})`)
    store.setMaster({ url: masterUrl, deviceId: j.deviceId, key: j.key, master: j.master, pairedAt: Date.now() })
    return { ok: true, deviceId: j.deviceId, master: j.master, restartRequired: role !== 'slave' }
  })

  route('/dsh-remote/unpair', ['POST'], async () => {
    store.setMaster(null)
    masterLink?.mux?.close(1000, 'unpaired')
    return { ok: true }
  })

  ctx.effect(() => ctx.webServer.register({
    kind: 'prefix',
    path: '/dsh-remote/devices',
    handler: async (req, res) => {
      const rejection = ctx.connection.requestRejection(req)
      if (rejection !== undefined) return sendJson(res, rejection, { error: 'rejected' })
      try {
        if (role !== 'master') throw httpErr(400, 'devices are managed on the master')
        if (req.method !== 'POST') throw httpErr(405, 'POST only')
        const m = new URL(req.url || '/', 'http://x').pathname.match(/^\/dsh-remote\/devices\/([a-z0-9-]+)\/(revoke|remove|sync)$/)
        if (!m) throw httpErr(404, 'not found')
        const [, id, action] = m
        if (action === 'revoke') { store.revokeDevice(id); links.get(id)?.mux.close(4401, 'revoked') }
        else if (action === 'remove') { store.removeDevice(id); links.get(id)?.mux.close(4401, 'removed') }
        else {
          const dev = store.devices()[id]
          if (!dev) throw httpErr(404, 'unknown device')
          const body = await readJson(req)
          const asList = (v) => (Array.isArray(v) ? v.map(String).filter(Boolean) : [])
          dev.sync = { enabled: body.enabled !== false, allow: asList(body.allow), deny: asList(body.deny), secrets: asList(body.secrets) }
          store.save()
          links.get(id)?.mux.event('sync-available', {})
        }
        pushPeers()
        sendJson(res, 200, { ok: true, devices: devicesView() })
      } catch (e) {
        sendJson(res, e.status || 500, { error: String(e.message || e) })
      }
    },
  }), 'dsh-remote: devices')

  route('/dsh-remote/sync', ['POST'], async () => {
    if (role === 'master') {
      manifestCache = null
      for (const l of links.values()) l.mux.event('sync-available', {})
      return { ok: true, pushed: links.size }
    }
    return runSlaveSync()
  })

  route('/dsh-remote/sync/status', ['GET'], async () => {
    if (role === 'master') {
      const m = await buildManifestCached()
      return { role, bundles: m.bundles, patchIds: m.patch.map((e) => e.id || (e.insert ? 'insert' : '?')), patchError: m.patchError || null, offerSecrets: m.secrets }
    }
    return { role, lastSync, synced: store.data.synced || {} }
  })

  // Session events of a session on any device (same auth as the UI; used by tooling).
  route('/dsh-remote/debug/inspect', ['GET'], async (_req, url) => {
    const sessionId = url.searchParams.get('sessionId')
    const device = url.searchParams.get('device') || self.id
    if (!sessionId) throw httpErr(400, 'sessionId required')
    if (device !== self.id) return callDevice(device, 'inspectSession', { sessionId }, 30000)
    return handlers.inspectSession({ sessionId })
  })

  route('/dsh-remote/new-session', ['POST'], async (req) => {
    const body = await readJson(req)
    const device = String(body.device || self.id)
    const r = await callDevice(device, 'newSession', { cwd: body.cwd, workspaceId: body.workspaceId })
    return { device, sessionId: r.sessionId, url: device === self.id ? `./#/session/${r.sessionId}` : `./r/${device}/#/session/${r.sessionId}` }
  })

  // Server-sent events for the client: devices changes, activity, sync results.
  route('/dsh-remote/events', ['GET'], async () => ({}))
  ctx.effect(() => {
    const dispose = ctx.webServer.register({
      kind: 'exact',
      path: '/dsh-remote/stream',
      handler: (req, res) => {
        const rejection = ctx.connection.requestRejection(req)
        if (rejection !== undefined) { res.statusCode = rejection; return res.end() }
        res.writeHead(200, { 'content-type': 'text/event-stream', 'cache-control': 'no-store', connection: 'keep-alive', 'x-accel-buffering': 'no' })
        res.write(': ok\n\n')
        const l = (ev) => res.write(`data: ${JSON.stringify(ev)}\n\n`)
        listeners.add(l)
        const ka = setInterval(() => res.write(': ka\n\n'), 20000)
        req.on('close', () => { listeners.delete(l); clearInterval(ka) })
      },
    })
    return dispose
  }, 'dsh-remote: event stream')

  // ------------------------------------------------------------------ /r/<device>/ proxy
  function parseRemote(urlPath) {
    const m = urlPath.match(/^\/r\/([a-z0-9-]+)(\/.*)?$/)
    if (!m) return null
    return { device: m[1], rest: m[2] || '/' }
  }

  ctx.effect(() => ctx.webServer.register({
    kind: 'prefix',
    path: '/r',
    handler: (req, res) => {
      const rejection = ctx.connection.requestRejection(req)
      if (rejection !== undefined) {
        res.writeHead(rejection, { 'content-type': 'text/plain; charset=utf-8' })
        return res.end(rejection === 401 ? 'dsh-remote: open this DSH first (authentication required)\n' : 'forbidden\n')
      }
      const url = new URL(req.url || '/', 'http://x')
      const p = parseRemote(url.pathname)
      if (!p) { res.statusCode = 404; return res.end() }
      // "/r/ai-pc" → "/r/ai-pc/" so relative URLs (<base href="./">) resolve under the mount.
      if (url.pathname === `/r/${p.device}`) {
        res.writeHead(301, { location: `/r/${p.device}/${url.search}${url.hash}` })
        return res.end()
      }
      if (p.device === self.id) {
        res.writeHead(302, { location: `/${url.search}` })
        return res.end()
      }
      const r = routeTo(p.device)
      if (!r) {
        res.writeHead(502, { 'content-type': 'text/html; charset=utf-8', 'cache-control': 'no-store' })
        return res.end(`<!doctype html><meta charset=utf-8><title>offline</title><body style="font:15px system-ui;padding:3em;background:#111;color:#ddd">
<h2>Device <code>${p.device}</code> is offline</h2><p>Its DSH is not linked right now. <a style="color:#8af" href="/">Back</a></p>`)
      }
      viewHttp(req, res, (kind, meta) => r.mux.open(kind, { ...meta, ...r.meta }), { rest: p.rest + url.search, basePath: `/r/${p.device}` })
    },
  }), 'dsh-remote: /r proxy')

  // Upgrades: DSH's webserver matches upgrade routes exactly, so register the Remote mux
  // path for each known device id (and re-register as devices appear).
  const upgradeRoutes = new Map()
  function ensureUpgradeRoute(device) {
    if (device === self.id || upgradeRoutes.has(device)) return
    const path = `/r/${device}${MUX_PATH}`
    try {
      const dispose = ctx.webServer.registerUpgrade({
        path,
        handler: (req, socket, head) => {
          if (ctx.connection.requestRejection(req) !== undefined) return rejectUpgrade(socket, 401, 'auth required')
          const r = routeTo(device)
          if (!r) return rejectUpgrade(socket, 502, 'device offline')
          const url = new URL(req.url || '/', 'http://x')
          viewUpgrade(req, socket, head, (kind, meta) => r.mux.open(kind, { ...meta, ...r.meta }), { rest: MUX_PATH + url.search })
        },
      })
      upgradeRoutes.set(device, dispose)
    } catch (e) {
      log.warn(`dsh-remote: upgrade route ${path}: ${e.message}`)
    }
  }
  const upgradeSync = setInterval(() => { for (const d of devicesView()) ensureUpgradeRoute(d.id) }, 2000)
  upgradeSync.unref?.()
  for (const d of Object.keys(store.devices())) ensureUpgradeRoute(d)
  ctx.effect(() => () => {
    clearInterval(upgradeSync)
    for (const dispose of upgradeRoutes.values()) { try { dispose() } catch { /* ignore */ } }
    upgradeRoutes.clear()
  }, 'dsh-remote: upgrade routes')

  // ------------------------------------------------------------------ agent tools
  // Registered only where ctx.tools exists (agent compositions). By default they are
  // offered on the master; a slave can enable them too (agentTools.enabled: true), in which
  // case it can only reach itself and, if the master allows peer control, other devices.
  const tools = svc(ctx, 'tools')
  const toolsOn = config.agentTools?.tools !== false && (role === 'master' || config.agentTools?.tools === true)
  if (tools && typeof tools.register === 'function' && toolsOn) {
    const T = (def, fn) => ({
      name: def.name,
      description: def.description,
      parameters: { type: 'object', properties: def.properties, required: def.required ?? [], additionalProperties: false },
      output: { schema: {}, render: (_a, v) => [{ type: 'text', text: typeof v === 'string' ? v : JSON.stringify(v, null, 1) }] },
      timeoutMs: def.timeoutMs,
      async execute(args, exec) {
        try { return JSON.parse(JSON.stringify((await fn(args ?? {}, exec)) ?? null)) } catch (e) { return { error: String(e?.message ?? e) } }
      },
    })
    const S = (type, description, extra = {}) => ({ type, description, ...extra })
    const DEVICE = S('string', 'Device id or name from remote_devices (e.g. "ai-pc"); "self" = this machine.')
    const CWD = S('string', 'Working directory on the device (absolute or ~/…; default: the device user\'s home).')
    const toolDefs = [
      T({
        name: 'remote_devices',
        description: 'List the DSH devices linked through dsh-remote (this master + paired slaves): id, name, online state, user, home, platform, and optionally their workspaces and recent sessions. Use the ids with remote_exec / remote_file / remote_task.',
        properties: { sessions: S('boolean', 'Include each online device\'s workspaces and recent sessions (default false).') },
      }, async (args) => {
        const devices = devicesView().filter((d) => !d.revoked)
        const out = []
        for (const d of devices) {
          const row = { id: d.id, name: d.name, role: d.role, online: !!d.online, self: !!d.self, platform: d.platform || (d.self ? `${process.platform}-${process.arch}` : undefined) }
          if (d.online) {
            try {
              const info = await callDevice(d.id, 'exec', { command: 'printf "%s\\n%s\\n%s" "$(id -un)" "$HOME" "$(uname -sr)"', timeoutMs: 8000 }, 12000)
              const [user, home, kernel] = String(info.stdout || '').split('\n')
              Object.assign(row, { user, home, kernel })
            } catch (e) { row.execError = e.message }
            if (args.sessions) {
              try {
                const s = await callDevice(d.id, 'sessions', {}, 15000)
                row.workspaces = s.workspaces
                row.sessions = (s.items || []).slice(0, 15).map(({ sessionId, title, running, cwd, updatedAt }) => ({ sessionId, title, running, cwd, updatedAt: new Date(updatedAt).toISOString() }))
              } catch (e) { row.sessionsError = e.message }
            }
          }
          out.push(row)
        }
        return { devices: out }
      }),
      T({
        name: 'remote_exec',
        description: 'Run a bash command on another DSH device (e.g. a slave) and return exit code, stdout and stderr. Runs as that device\'s DSH user, in `bash -lc`, non-interactive (no TTY, GIT_TERMINAL_PROMPT=0). Use for quick deterministic steps: git clone/pull, builds, test runs, inspecting files. For long multi-step work prefer remote_task.',
        properties: {
          device: DEVICE,
          command: S('string', 'The bash command line.'),
          cwd: CWD,
          timeoutMs: S('integer', 'Kill the command after this many ms (default 120000, max 1800000).'),
          stdin: S('string', 'Optional data written to stdin.'),
        },
        required: ['device', 'command'],
        timeoutMs: 31 * 60 * 1000,
      }, async (args) => {
        const device = resolveDevice(args.device)
        const t = Math.min(Math.max(Number(args.timeoutMs) || 120000, 1000), 1800000)
        const r = await callDevice(device, 'exec', { command: args.command, cwd: args.cwd, timeoutMs: t, stdin: args.stdin }, t + 15000)
        return { device, ...r }
      }),
      T({
        name: 'remote_file',
        description: 'Files on another DSH device. action=read (path, offset, limit; binary comes back base64), write (path, content, encoding utf8|base64, append), list (directory entries).',
        properties: {
          device: DEVICE,
          action: S('string', 'read | write | list', { enum: ['read', 'write', 'list'] }),
          path: S('string', 'File or directory path (absolute or relative to cwd / home).'),
          cwd: CWD,
          content: S('string', 'write: file content.'),
          encoding: S('string', 'write: utf8 (default) or base64.', { enum: ['utf8', 'base64'] }),
          append: S('boolean', 'write: append instead of replace.'),
          offset: S('integer', 'read: byte offset.'),
          limit: S('integer', 'read: max bytes (default/max 4 MiB).'),
          hidden: S('boolean', 'list: include dotfiles.'),
        },
        required: ['device', 'action', 'path'],
      }, async (args) => {
        const device = resolveDevice(args.device)
        const method = { read: 'readFile', write: 'writeFile', list: 'listDir' }[args.action]
        if (!method) throw httpErr(400, 'action must be read, write or list')
        return { device, ...(await callDevice(device, method, args, 30000)) }
      }),
      T({
        name: 'remote_task',
        description: 'Delegate a task to the AI agent running on another DSH device, so the work executes there with that device\'s own tools and model, and get its final answer. action=run (default): create a session on the device (in cwd, attached to that workspace) or continue sessionId, send prompt, and wait up to timeoutMs for the turn to finish. action=status: collect the latest answer of sessionId. action=cancel: stop it. The session stays visible on that device (Devices panel / /r/<device>/). Write a complete, self-contained prompt — the remote agent has no access to this conversation.',
        properties: {
          device: DEVICE,
          action: S('string', 'run (default) | status | cancel', { enum: ['run', 'status', 'cancel'] }),
          prompt: S('string', 'run: the full task for the remote agent.'),
          sessionId: S('string', 'Continue / poll / cancel this session on the device.'),
          cwd: CWD,
          title: S('string', 'run, new session: session title.'),
          permission: S('string', 'run: permission preset for the remote session, e.g. "danger-full-access" when the job must run tools outside the workspace sandbox (test suites that spawn processes, git credential writes). Default: the device\'s default preset.'),
          wait: S('boolean', 'run: wait for completion (default true). false = start and return the sessionId.'),
          timeoutMs: S('integer', 'run: how long to wait (default 1200000 = 20 min, max 2 h). On timeout the task keeps running; poll with action=status.'),
        },
        required: ['device'],
        timeoutMs: 2 * 60 * 60 * 1000 + 60000,
      }, async (args, exec) => {
        const device = resolveDevice(args.device)
        const action = args.action || 'run'
        if (action === 'status') return { device, ...(await callDevice(device, 'taskStatus', { sessionId: args.sessionId }, 30000)) }
        if (action === 'cancel') return { device, ...(await callDevice(device, 'taskCancel', { sessionId: args.sessionId }, 15000)) }
        const t = Math.min(Math.max(Number(args.timeoutMs) || 1200000, 10000), 2 * 60 * 60 * 1000)
        const r = await callDevice(device, 'task', {
          prompt: args.prompt, sessionId: args.sessionId, cwd: args.cwd, title: args.title, permission: args.permission,
          wait: args.wait !== false, timeoutMs: t,
        }, t + 30000)
        return { device, ...r, url: device === self.id ? `#/session/${r.sessionId}` : `/r/${device}/#/session/${r.sessionId}` }
      }),
    ]
    ctx.effect(function* () { for (const t of toolDefs) yield tools.register(t) }, 'dsh-remote: agent tools')
  }

  log.info?.(`dsh-remote: ${role} "${self.name}" (${self.id}) ready`)
}