import b4a from 'b4a'
import fs from '#host-fs'
import unixPathResolve from 'unix-path-resolve'
import { raceWithAbortAndTimeout } from './bare-os-abort.js'
import {
  isDelegateKindAllowed,
  loadBareOsHostDelegates,
  parseDelegateAllowSet
} from './host-delegate-registry.js'
import { bareOsDelegateRateAllow } from './delegate-rate-limit.js'
import {
  bareOsDelegateConcurrentExit,
  bareOsDelegateConcurrentTryEnter
} from './bare-os-delegate-concurrent.js'

const AsyncFunction = Object.getPrototypeOf(async function () {}).constructor
/** @type {Map<string, number>} */
const workerHeartbeatByKey = new Map()

/**
 * @param {string} key
 */
export function bareOsNoteWorkerHeartbeat(key) {
  workerHeartbeatByKey.set(String(key || '').slice(0, 128), Date.now())
}

/**
 * @param {{ staleAfterMs?: number }} [opts]
 */
export function bareOsWorkerHeartbeatSnapshot(opts = {}) {
  const now = Date.now()
  const staleAfterMs = Math.max(
    100,
    Math.min(300000, Number(opts.staleAfterMs) || 30000)
  )
  /** @type {{ key: string, lastMs: number, stale: boolean }[]} */
  const rows = []
  for (const [key, lastMs] of workerHeartbeatByKey.entries()) {
    rows.push({
      key,
      lastMs,
      stale: now - lastMs > staleAfterMs
    })
  }
  return {
    schema: 1,
    atMs: now,
    staleAfterMs,
    workers: rows
  }
}

/**
 * Persist non-secret liveness checkpoint when enabled.
 * @param {Record<string, string | undefined> | null | undefined} env
 */
export async function bareOsPersistWorkerLivenessCheckpoint(env) {
  const p = String(env?.BARE_OS_WORKER_LIVENESS_PATH || '').trim()
  if (!p || (!p.startsWith('/') && !p.startsWith('./'))) return false
  try {
    await fs.promises.writeFile(
      p,
      JSON.stringify(bareOsWorkerHeartbeatSnapshot(), null, 2) + '\n'
    )
    return true
  } catch {
    return false
  }
}

/**
 * Pear/Bare cannot resolve `node:module`. Holepunch's `bare-module` exposes the same `createRequire(parentURL)` as Node. Only called from bin-worker offload after the Node early-return in `tryRunBinInBareWorker`.
 * @returns {((specifier: string) => unknown) | null}
 */
async function bareOsCreateRequireFromMetaUrl() {
  try {
    const bm = await import('bare-module')
    const createRequire = bm.createRequire || bm.default?.createRequire
    if (typeof createRequire !== 'function') return null
    return createRequire(import.meta.url)
  } catch {
    return null
  }
}

/**
 * @param {string} cmd
 * @param {Record<string, string | undefined> | null | undefined} env
 */
const _BIN_WORKER_TEXTPROC = new Set([
  'awk',
  'sed',
  'jq',
  'cut',
  'tr',
  'sort',
  'uniq'
])

const _BIN_WORKER_MATHPROC = new Set(['bc', 'dc'])

const _BIN_WORKER_IOPROC = new Set(['cat', 'head', 'tail'])

const _BIN_WORKER_MEDIAPROC = new Set(['ffmpeg', 'ffprobe'])

/** Crypto-class `/bin` entries (e.g. openssl) under `cryptoproc:*` (word 11). */
const _BIN_WORKER_CRYPTOPROC = new Set(['openssl'])

/** Indexer-adjacent tools under `indexerproc:*` (word 11; reserved; extend when `/bin` gains indexer helpers). */
const _BIN_WORKER_INDEXERPROC = new Set([])

/** VFS metadata utilities under `metaproc:*` (ACL / xattr sidecars). */
const _BIN_WORKER_METAPROC = new Set(['getfacl', 'setfacl', 'xattr'])

/** Process/shell-adjacent builtins allowed under `sysproc:*` (documentary group; bare-process-class). */
const _BIN_WORKER_SYSPROC = new Set([
  'pwd',
  'echo',
  'printenv',
  'uname',
  'id',
  'env',
  'true',
  'false'
])

/**
 * @param {string} cmd
 * @param {Record<string, string | undefined> | null | undefined} env
 */
function binWorkerOffloadEnabled(cmd, env) {
  if (!env) return false
  if (
    env.BARE_OS_BIN_WORKER_OFFLOAD !== '1' &&
    env.BARE_OS_BIN_WORKER_OFFLOAD !== 'true'
  ) {
    return false
  }
  const allowRaw = String(env.BARE_OS_BIN_WORKER_ALLOW || '').trim()
  if (!allowRaw) return cmd === 'awk' || cmd === 'sed' || cmd === 'jq'
  const parts = allowRaw
    .split(',')
    .map((s) => s.trim())
    .filter(Boolean)
  for (const p of parts) {
    if (p === 'textproc:*') {
      if (_BIN_WORKER_TEXTPROC.has(cmd)) return true
      continue
    }
    if (p === 'mathproc:*') {
      if (_BIN_WORKER_MATHPROC.has(cmd)) return true
      continue
    }
    if (p === 'ioproc:*') {
      if (_BIN_WORKER_IOPROC.has(cmd)) return true
      continue
    }
    if (p === 'mediaproc:*') {
      if (_BIN_WORKER_MEDIAPROC.has(cmd)) return true
      continue
    }
    if (p === 'sysproc:*') {
      if (_BIN_WORKER_SYSPROC.has(cmd)) return true
      continue
    }
    if (p === 'cryptoproc:*') {
      if (_BIN_WORKER_CRYPTOPROC.has(cmd)) return true
      continue
    }
    if (p === 'indexerproc:*') {
      if (_BIN_WORKER_INDEXERPROC.has(cmd)) return true
      continue
    }
    if (p === 'metaproc:*') {
      if (_BIN_WORKER_METAPROC.has(cmd)) return true
      continue
    }
    if (p.endsWith(':*')) {
      const pre = p.slice(0, -2)
      if (pre === 'textproc' && _BIN_WORKER_TEXTPROC.has(cmd)) return true
      if (pre === 'mathproc' && _BIN_WORKER_MATHPROC.has(cmd)) return true
      if (pre === 'ioproc' && _BIN_WORKER_IOPROC.has(cmd)) return true
      if (pre === 'mediaproc' && _BIN_WORKER_MEDIAPROC.has(cmd)) return true
      if (pre === 'sysproc' && _BIN_WORKER_SYSPROC.has(cmd)) return true
      if (pre === 'cryptoproc' && _BIN_WORKER_CRYPTOPROC.has(cmd)) return true
      if (pre === 'indexerproc' && _BIN_WORKER_INDEXERPROC.has(cmd)) return true
      if (pre === 'metaproc' && _BIN_WORKER_METAPROC.has(cmd)) return true
      continue
    }
    if (p === cmd) return true
  }
  return false
}

/**
 * @param {Record<string, unknown>} ctx
 * @param {string[]} argv
 * @param {string} source
 * @returns {Promise<boolean>} true when the worker handled the command
 */
async function tryRunBinInBareWorker(ctx, argv, source) {
  if (
    typeof process !== 'undefined' &&
    process.release &&
    process.release.name === 'node'
  ) {
    return false
  }
  const cmd = argv[0]
  const env = ctx.vfs?.env
  if (!binWorkerOffloadEnabled(cmd, env)) return false
  const reportFallback = (reason, err) => {
    if (!env) return
    const on =
      env.BARE_OS_BIN_WORKER_REPORT_FALLBACK === '1' ||
      env.BARE_OS_BIN_WORKER_REPORT_FALLBACK === 'true'
    if (!on) return
    const msg = err && err.message ? `${reason}: ${err.message}` : String(reason)
    try {
      ctx.console?.error?.(`[bare-os] bin-worker fallback for ${cmd}: ${msg}`)
    } catch {
      /* ignore */
    }
  }
  try {
    const req = await bareOsCreateRequireFromMetaUrl()
    if (!req) {
      reportFallback('bare-module createRequire unavailable')
      return false
    }
    const { runBinOffloaded } = req('./bare-os-bin-offload-worker.cjs')
    const wasmRaw = env && String(env.BARE_OS_BIN_WORKER_WASM_MS_MAX || '').trim()
    const wasmN = wasmRaw ? Number.parseInt(wasmRaw, 10) : 0
    const maxWasmMs =
      Number.isFinite(wasmN) && wasmN > 0
        ? Math.min(wasmN, 3_600_000)
        : 0
    const msg = await runBinOffloaded(
      { source, argv },
      maxWasmMs > 0 ? { maxWasmMs } : undefined
    )
    if (!msg || msg.ok === false) {
      reportFallback(
        msg && typeof msg === 'object' && msg.reason ? `worker rejected (${msg.reason})` : 'worker rejected'
      )
      return false
    }
    const logs = Array.isArray(msg.logs) ? msg.logs : []
    const errs = Array.isArray(msg.errs) ? msg.errs : []
    for (const line of logs) ctx.console.log(line)
    for (const line of errs) ctx.console.error(line)
    if (Number(msg.droppedLogs) > 0 || Number(msg.droppedErrs) > 0) {
      ctx.console.error(
        `[bare-os] bin-worker output truncated for ${cmd} (dropped logs=${Number(msg.droppedLogs) || 0}, errs=${Number(msg.droppedErrs) || 0})`
      )
    }
    ctx.exitCode =
      msg.exitCode != null ? Number(msg.exitCode) || 0 : 0
    return true
  } catch (e) {
    reportFallback('worker exception', /** @type {Error} */ (e))
    return false
  }
}

/** @type {ReturnType<loadBareOsHostDelegates>} */
let _delegateCache = null
function bareOsHostDelegates() {
  if (!_delegateCache) _delegateCache = loadBareOsHostDelegates()
  return _delegateCache
}

/**
 * @param {Record<string, unknown>} ctx
 * @param {string} kind
 * @param {string[]} argv
 */
async function auditDelegateJson(ctx, kind, argv) {
  const env = ctx.vfs?.env
  if (!env || (env.BARE_OS_AUDIT !== '1' && env.BARE_OS_AUDIT !== 'true'))
    return
  if (env.BARE_OS_AUDIT_JSON !== '1' && env.BARE_OS_AUDIT_JSON !== 'true')
    return
  const { appendVarLog, AUDIT_LOG } = await import('./bare-os-var-log.js')
  const args = argv.slice(0, 24).map((a) => {
    const s = String(a)
    return s.length > 160 ? s.slice(0, 160) + '…' : s
  })
  void appendVarLog(
    ctx,
    AUDIT_LOG,
    'json',
    JSON.stringify({
      auditSchemaVersion: 8,
      requestSmugglingClass: 'none',
      type: 'delegate',
      kind,
      ts: Date.now(),
      argv: args,
      argvRawCount: argv.length,
      argvTruncated: argv.length > 24,
      sessionId: String(env.BARE_OS_SESSION_ID || '').trim() || undefined,
      delegateChainDepth: 1,
      delegateChainTruncated: false
    })
  )
}

/** Strip one leading Unix shebang so AsyncFunction does not see `#!` as invalid syntax. */
function stripShebang(source) {
  if (typeof source !== 'string' || !source.startsWith('#!')) return source
  const m = source.match(/^#![^\n]*\n/)
  return m ? source.slice(m[0].length) : source
}

/**
 * Execute kernel source from Hyperdrive (trusted). Expects top-level `async function start(ctx)`.
 * @param {string} source
 * @param {Record<string, unknown>} ctx
 */
export async function runKernelFromSource(source, ctx) {
  const fn = new AsyncFunction(
    'ctx',
    `${source}\nif (typeof start !== 'function') throw new Error('kernel must define async function start')\nreturn start(ctx)\n`
  )
  return fn(ctx)
}

/**
 * Evaluate user script source: top-level statements run in an async function with `ctx` and `argv`.
 * If the script defines a top-level `run` function, it is awaited after the body (same as `/bin` utilities).
 *
 * @param {Record<string, unknown>} ctx
 * @param {string} src
 * @param {string[]} argv
 * @param {string} [_label] reserved for diagnostics
 */
/**
 * Evaluate user script source (same contract as `/bin` utilities).
 * @param {Record<string, unknown>} ctx
 * @param {string} src
 * @param {string[]} argv
 * @param {string} [_label]
 */
export async function runUserScriptFromSource(ctx, src, argv, _label = argv[0]) {
  try {
    const body = stripShebang(src)
    const sessionConsole =
      ctx &&
      ctx.console &&
      typeof ctx.console === 'object' &&
      typeof ctx.console.log === 'function'
        ? ctx.console
        : null
    const prelude =
      sessionConsole != null
        ? 'var console = ctx.console;\n'
        : ''
    const fn = new AsyncFunction(
      'ctx',
      'argv',
      `${prelude}${body}\nif (typeof run === 'function') await run(ctx, argv)\n`
    )
    await fn(ctx, argv)
    if (ctx.exitCode === undefined || ctx.exitCode === null) ctx.exitCode = 0
    return
  } catch (e) {
    const msg = e?.message || String(e)
    const stack = e?.stack
    if (typeof ctx.console?.error === 'function') {
      ctx.console.error(msg)
      if (stack && typeof stack === 'string' && stack !== msg) {
        const lines = stack.split('\n').slice(1, 4)
        for (const line of lines) {
          if (line && line.trim()) ctx.console.error(line.trim())
        }
      }
    }
    ctx.exitCode = 1
    ctx.bareOsScriptCompletedWithCatch = true
  }
}

/**
 * Run a command: bare `*.js` in cwd (before PATH), path script on any routed drive, then PATH on system.
 * @param {Record<string, unknown>} ctx
 * @param {string[]} argv
 * @param {import('./bare-os-abort.js').BareOsAbortOpts} [runOpts]
 */
export async function runBinCommand(ctx, argv, runOpts) {
  const env = ctx?.vfs?.env
  const defTo = Number.parseInt(
    String(env?.BARE_OS_RUNBIN_DEFAULT_TIMEOUT_MS || ''),
    10
  )
  /** @type {import('./bare-os-abort.js').BareOsAbortOpts | undefined} */
  let merged =
    runOpts && typeof runOpts === 'object' ? { ...runOpts } : undefined
  if (Number.isFinite(defTo) && defTo > 0) {
    const cap = Math.min(defTo, 3_600_000)
    if (!merged) merged = { timeoutMs: cap }
    else if (merged.timeoutMs == null) merged.timeoutMs = cap
  }
  const bridgeOn =
    env?.BARE_OS_BARE_SUBPROCESS_BRIDGE === '1' ||
    env?.BARE_OS_BARE_SUBPROCESS_BRIDGE === 'true'
  if (bridgeOn) {
    const subMs = Number.parseInt(
      String(env?.BARE_OS_BARE_SUBPROCESS_TIMEOUT_MS || ''),
      10
    )
    if (Number.isFinite(subMs) && subMs > 0) {
      const cap = Math.min(subMs, 3_600_000)
      if (!merged) merged = { timeoutMs: cap }
      else if (merged.timeoutMs == null) merged.timeoutMs = cap
    }
  }
  return raceWithAbortAndTimeout(
    runBinCommandInner(ctx, argv),
    merged,
    'runBinCommand'
  )
}

/**
 * @param {Record<string, unknown>} ctx
 * @param {string[]} argv
 */
async function runBinCommandInner(ctx, argv) {
  const cmd = argv[0]
  const systemDrive = ctx.drive
  const vfs = ctx.vfs
  const pathEnv = (vfs && vfs.env && vfs.env.PATH) || '/bin'
  const allow = parseDelegateAllowSet(vfs?.env)
  const argvTail = argv.length > 1 ? argv.slice(1) : []

  // `.sh` scripts should execute through the shell frontend, not JS eval.
  const runViaSh = (scriptPath) => runBinCommandInner(ctx, ['sh', scriptPath, ...argvTail])

  for (const del of bareOsHostDelegates()) {
    if (!del.shouldDelegate(cmd)) continue
    if (!isDelegateKindAllowed(del.kind, allow)) {
      // `curl` / `wget` have drive-resident `/bin` scripts that call
      // `ctx.bareOsRunCurlCli` / `ctx.bareOsRunWgetCli` (same fetch backends).
      if (del.kind === 'curl' || del.kind === 'wget') continue
      ctx.console.error('delegate denied by BARE_OS_DELEGATE_ALLOW: ' + del.kind)
      ctx.exitCode = 126
      return
    }
    if (!bareOsDelegateRateAllow(del.kind, vfs?.env)) {
      ctx.console.error('delegate rate limit exceeded: ' + del.kind)
      ctx.exitCode = 126
      return
    }
    const env = vfs?.env
    const auditOnly =
      env &&
      (env.BARE_OS_DELEGATE_AUDIT_ONLY === '1' ||
        env.BARE_OS_DELEGATE_AUDIT_ONLY === 'true') &&
      (env.BARE_OS_AUDIT === '1' || env.BARE_OS_AUDIT === 'true')
    if (auditOnly) {
      await auditDelegateJson(ctx, del.kind, argv)
      const { appendVarLog, AUDIT_LOG } = await import('./bare-os-var-log.js')
      void appendVarLog(
        ctx,
        AUDIT_LOG,
        'delegate-audit-only',
        del.kind + ' ' + argv.slice(0, 8).join(' ')
      )
      ctx.console.error(
        '[bare-os] delegate audit-only (skipped run): ' + del.kind
      )
      ctx.exitCode = 0
      return
    }
    if (!bareOsDelegateConcurrentTryEnter(del.kind, vfs?.env)) {
      ctx.console.error('delegate concurrency limit exceeded: ' + del.kind)
      ctx.exitCode = 126
      return
    }
    await auditDelegateJson(ctx, del.kind, argv)
    try {
      return await del.run(ctx, argv)
    } finally {
      bareOsDelegateConcurrentExit(del.kind)
    }
  }

  if (cmd.includes('/')) {
    if (cmd.endsWith('.sh')) return runViaSh(cmd)
    const abs = vfs.resolveLogical(cmd)
    const { drive, path } = vfs.route(abs)
    const buf = await drive.get(path, { follow: true })
    if (!buf) {
      ctx.console.log('not found: ' + cmd)
      ctx.exitCode = 127
      return
    }
    const source = b4a.toString(buf)
    if (await tryRunBinInBareWorker(ctx, argv, source)) return
    return runUserScriptFromSource(ctx, source, argv, cmd)
  }

  // `script.js` in $PWD before PATH (same VFS routing as `./script.js`).
  if (cmd.endsWith('.sh')) {
    const abs = vfs.resolveLogical(cmd)
    const { drive, path } = vfs.route(abs)
    const buf = await drive.get(path, { follow: true })
    if (buf) return runViaSh(cmd)
  }

  // `script.js` in $PWD before PATH (same VFS routing as `./script.js`).
  if (cmd.endsWith('.js')) {
    const abs = vfs.resolveLogical(cmd)
    const { drive, path } = vfs.route(abs)
    const buf = await drive.get(path, { follow: true })
    if (buf) {
      const source = b4a.toString(buf)
      if (await tryRunBinInBareWorker(ctx, argv, source)) return
      return runUserScriptFromSource(ctx, source, argv, cmd)
    }
  }

  const dirs = pathEnv.split(':').filter(Boolean)
  for (const dir of dirs) {
    const p = unixPathResolve(dir, cmd)
    const buf = await systemDrive.get(p, { follow: true })
    if (buf) {
      const source = b4a.toString(buf)
      if (await tryRunBinInBareWorker(ctx, argv, source)) return
      return runUserScriptFromSource(ctx, source, argv, p)
    }
  }

  ctx.console.log('unknown command: ' + cmd)
  ctx.exitCode = 127
}

/**
 * Resolve an executable name on PATH (system drive only).
 * @param {Record<string, unknown>} ctx
 * @param {string} name
 * @returns {Promise<string | null>}
 */
export async function resolveBinInPath(ctx, name) {
  if (!name || name.includes('/')) return null
  const systemDrive = ctx.drive
  const vfs = ctx.vfs
  const pathEnv = (vfs && vfs.env && vfs.env.PATH) || '/bin'
  const dirs = pathEnv.split(':').filter(Boolean)
  for (const dir of dirs) {
    const p = unixPathResolve(dir, name)
    const buf = await systemDrive.get(p, { follow: true })
    if (buf) return p
  }
  return null
}