#!/usr/bin/env node

import crypto from 'node:crypto'
import fs from 'node:fs'
import http from 'node:http'
import path from 'node:path'
import { fileURLToPath } from 'node:url'

const MAX_CONTROL_BYTES = 1024 * 1024
const VERSION_PATTERN = /^(0|[1-9]\d*)\.(0|[1-9]\d*)\.(0|[1-9]\d*)(?:-[0-9A-Za-z.-]+)?(?:\+[0-9A-Za-z.-]+)?$/
const SHA256_PATTERN = /^[a-f0-9]{64}$/

const fail = (code) => {
  throw new Error(code)
}

const sha256 = (bytes) => crypto.createHash('sha256').update(bytes).digest('hex')

const requireText = (value, code) => {
  if (typeof value !== 'string' || value.trim() === '') fail(code)
  return value.trim()
}

function trustedRegularFile(file, { enforceRootOwner, maxBytes = null }) {
  const info = fs.lstatSync(file)
  if (!info.isFile() || info.isSymbolicLink()) fail('HOLOLAKE_RELEASE_FILE_NOT_REGULAR')
  if ((info.mode & 0o022) !== 0) fail('HOLOLAKE_RELEASE_FILE_WRITABLE_BY_NON_OWNER')
  if (enforceRootOwner && info.uid !== 0) fail('HOLOLAKE_RELEASE_FILE_NOT_ROOT_OWNED')
  if (maxBytes !== null && info.size > maxBytes) fail('HOLOLAKE_RELEASE_CONTROL_FILE_TOO_LARGE')
  return info
}

function safeRelative(root, value, code) {
  const relative = requireText(value, code)
  if (path.isAbsolute(relative) || relative.includes('\0')) fail(code)
  const resolved = path.resolve(root, relative)
  if (!resolved.startsWith(`${root}${path.sep}`)) fail(code)
  return resolved
}

function readTrustedJson(file, options) {
  trustedRegularFile(file, { ...options, maxBytes: MAX_CONTROL_BYTES })
  return { bytes: fs.readFileSync(file), value: JSON.parse(fs.readFileSync(file, 'utf8')) }
}

function validatePlatform(platform, releaseDirectory, enforceRootOwner) {
  const url = new URL(requireText(platform?.url, 'HOLOLAKE_RELEASE_PACKAGE_URL_REQUIRED'))
  if (url.protocol !== 'https:' || url.username || url.password || url.search || url.hash) {
    fail('HOLOLAKE_RELEASE_PACKAGE_URL_INVALID')
  }
  const packageName = decodeURIComponent(path.posix.basename(url.pathname))
  if (!packageName || packageName === '.' || packageName === '..') fail('HOLOLAKE_RELEASE_PACKAGE_NAME_INVALID')
  const packagePath = safeRelative(releaseDirectory, packageName, 'HOLOLAKE_RELEASE_PACKAGE_PATH_INVALID')
  const packageInfo = trustedRegularFile(packagePath, { enforceRootOwner })
  if (!Number.isSafeInteger(platform.size) || platform.size <= 0 || platform.size !== packageInfo.size) {
    fail('HOLOLAKE_RELEASE_PACKAGE_SIZE_MISMATCH')
  }
  if (!SHA256_PATTERN.test(platform.sha256 || '') || sha256(fs.readFileSync(packagePath)) !== platform.sha256) {
    fail('HOLOLAKE_RELEASE_PACKAGE_SHA256_MISMATCH')
  }
  requireText(platform.signature, 'HOLOLAKE_RELEASE_PACKAGE_SIGNATURE_REQUIRED')
  const codeReceiptId = requireText(platform.platformCodeSignatureReceipt, 'HOLOLAKE_RELEASE_CODESIGN_RECEIPT_REQUIRED')
  const notarizationReceiptId = requireText(platform.notarizationReceipt, 'HOLOLAKE_RELEASE_NOTARIZATION_RECEIPT_REQUIRED')
  const codeReceipt = readTrustedJson(
    safeRelative(releaseDirectory, `${codeReceiptId}.json`, 'HOLOLAKE_RELEASE_CODESIGN_RECEIPT_PATH_INVALID'),
    { enforceRootOwner },
  ).value
  const notarizationReceipt = readTrustedJson(
    safeRelative(releaseDirectory, `${notarizationReceiptId}.json`, 'HOLOLAKE_RELEASE_NOTARIZATION_RECEIPT_PATH_INVALID'),
    { enforceRootOwner },
  ).value
  if (
    codeReceipt?.schema !== 'hololake.platform-code-signature-receipt/v1' ||
    codeReceipt?.state !== 'DEVELOPER_ID_SIGNATURE_STRICT_AND_GATEKEEPER_ACCEPTED'
  ) fail('HOLOLAKE_RELEASE_CODESIGN_RECEIPT_INVALID')
  if (
    notarizationReceipt?.schema !== 'hololake.apple-notarization-receipt/v1' ||
    notarizationReceipt?.state !== 'APPLE_NOTARIZATION_ACCEPTED_AND_STAPLED'
  ) fail('HOLOLAKE_RELEASE_NOTARIZATION_RECEIPT_INVALID')
  return { pathname: url.pathname, file: packagePath, size: packageInfo.size }
}

function loadActiveRelease(stateRoot, enforceRootOwner) {
  const activationPath = path.join(stateRoot, 'ACTIVE.json')
  if (!fs.existsSync(activationPath)) {
    return { state: 'EMPTY_FAIL_CLOSED', release: null, reasonCode: null }
  }
  const activation = readTrustedJson(activationPath, { enforceRootOwner }).value
  if (
    activation?.schema !== 'hololake.release-broadcast-activation/v1' ||
    activation?.state !== 'HUMAN_APPROVED_SIGNED_NOTARIZED_RELEASE_ACTIVE'
  ) fail('HOLOLAKE_RELEASE_ACTIVATION_INVALID')
  const releaseId = requireText(activation.releaseId, 'HOLOLAKE_RELEASE_ID_REQUIRED')
  const version = requireText(activation.version, 'HOLOLAKE_RELEASE_VERSION_REQUIRED')
  if (!VERSION_PATTERN.test(version)) fail('HOLOLAKE_RELEASE_VERSION_INVALID')
  if (!SHA256_PATTERN.test(activation.broadcastSha256 || '')) fail('HOLOLAKE_RELEASE_BROADCAST_SHA256_INVALID')
  requireText(activation.humanApprovalReceipt, 'HOLOLAKE_RELEASE_HUMAN_APPROVAL_REQUIRED')
  const broadcastPath = safeRelative(stateRoot, activation.broadcastRelativePath, 'HOLOLAKE_RELEASE_BROADCAST_PATH_INVALID')
  const pipelinePath = safeRelative(stateRoot, activation.pipelineReceiptRelativePath, 'HOLOLAKE_RELEASE_PIPELINE_PATH_INVALID')
  const broadcastDocument = readTrustedJson(broadcastPath, { enforceRootOwner })
  const pipelineReceipt = readTrustedJson(pipelinePath, { enforceRootOwner }).value
  if (sha256(broadcastDocument.bytes) !== activation.broadcastSha256) fail('HOLOLAKE_RELEASE_BROADCAST_SHA256_MISMATCH')
  if (
    pipelineReceipt?.schema !== 'hololake.signed-release-pipeline-receipt/v1' ||
    pipelineReceipt?.state !== 'SIGNED_NOTARIZED_RELEASE_BROADCAST_READY_FOR_JD_CONTROLLER_UPLOAD' ||
    pipelineReceipt?.broadcastSha256 !== activation.broadcastSha256 ||
    pipelineReceipt?.automaticUpload !== false ||
    pipelineReceipt?.automaticActivation !== false
  ) fail('HOLOLAKE_RELEASE_PIPELINE_RECEIPT_INVALID')
  const broadcast = broadcastDocument.value
  if (
    broadcast?.schema !== 'hololake.release-broadcast/v1' ||
    broadcast?.releaseId !== releaseId ||
    broadcast?.version !== version ||
    broadcast?.hololake?.restart?.required !== true ||
    broadcast?.hololake?.restart?.automaticAllowed !== false ||
    broadcast?.hololake?.rollback?.supported !== true ||
    broadcast?.hololake?.rollback?.healthReceiptRequired !== true ||
    !broadcast.platforms || typeof broadcast.platforms !== 'object' || Array.isArray(broadcast.platforms) ||
    Object.keys(broadcast.platforms).length === 0
  ) fail('HOLOLAKE_RELEASE_BROADCAST_INVALID')
  const releaseDirectory = path.dirname(broadcastPath)
  const packages = new Map()
  for (const platform of Object.values(broadcast.platforms)) {
    const accepted = validatePlatform(platform, releaseDirectory, enforceRootOwner)
    if (packages.has(accepted.pathname)) fail('HOLOLAKE_RELEASE_PACKAGE_ROUTE_COLLISION')
    packages.set(accepted.pathname, accepted)
  }
  return {
    state: 'READY_SIGNED_NOTARIZED_BROADCAST',
    release: { releaseId, version, broadcastBytes: broadcastDocument.bytes, packages },
    reasonCode: null,
  }
}

export function loadRuntimeState(stateRoot, { enforceRootOwner = false } = {}) {
  const resolvedRoot = path.resolve(stateRoot)
  try {
    return loadActiveRelease(resolvedRoot, enforceRootOwner)
  } catch (error) {
    return {
      state: 'LOCKED_INVALID_RELEASE_EVIDENCE',
      release: null,
      reasonCode: error instanceof Error ? error.message : 'HOLOLAKE_RELEASE_UNKNOWN_FAILURE',
    }
  }
}

function jsonResponse(response, status, value) {
  const body = Buffer.from(`${JSON.stringify(value)}\n`)
  response.writeHead(status, {
    'Content-Type': 'application/json; charset=utf-8',
    'Content-Length': body.length,
    'Cache-Control': 'no-store',
    'X-Content-Type-Options': 'nosniff',
  })
  response.end(body)
}

export function createReleaseServer(runtimeState) {
  return http.createServer((request, response) => {
    response.setHeader('X-Content-Type-Options', 'nosniff')
    if (!['GET', 'HEAD'].includes(request.method || '')) {
      response.writeHead(405, { Allow: 'GET, HEAD', 'Cache-Control': 'no-store' })
      return response.end()
    }
    const pathname = new URL(request.url || '/', 'http://127.0.0.1').pathname
    if (pathname === '/health') {
      const status = runtimeState.state === 'LOCKED_INVALID_RELEASE_EVIDENCE' ? 503 : 200
      return jsonResponse(response, status, {
        schema: 'hololake.release-broadcast-health/v1',
        state: runtimeState.state,
        updateAvailable: runtimeState.release !== null,
        automaticUpload: false,
        automaticActivation: false,
        upstreamUpdateSources: [],
        ...(runtimeState.release ? { releaseId: runtimeState.release.releaseId, version: runtimeState.release.version } : {}),
        ...(runtimeState.reasonCode ? { reasonCode: runtimeState.reasonCode } : {}),
      })
    }
    if (pathname === '/latest.json') {
      if (runtimeState.state === 'EMPTY_FAIL_CLOSED') {
        response.writeHead(204, { 'Cache-Control': 'no-store' })
        return response.end()
      }
      if (!runtimeState.release) {
        response.writeHead(503, { 'Cache-Control': 'no-store' })
        return response.end()
      }
      response.writeHead(200, {
        'Content-Type': 'application/json; charset=utf-8',
        'Content-Length': runtimeState.release.broadcastBytes.length,
        'Cache-Control': 'no-store',
        'X-Content-Type-Options': 'nosniff',
      })
      return response.end(request.method === 'HEAD' ? undefined : runtimeState.release.broadcastBytes)
    }
    const packageFile = runtimeState.release?.packages.get(pathname)
    if (packageFile) {
      response.writeHead(200, {
        'Content-Type': 'application/octet-stream',
        'Content-Length': packageFile.size,
        'Cache-Control': 'public, max-age=31536000, immutable',
        'X-Content-Type-Options': 'nosniff',
      })
      if (request.method === 'HEAD') return response.end()
      return fs.createReadStream(packageFile.file).on('error', () => response.destroy()).pipe(response)
    }
    response.writeHead(404, { 'Cache-Control': 'no-store' })
    response.end()
  })
}

export function main(env = process.env) {
  const host = env.HOLOLAKE_RELEASE_HOST || '127.0.0.1'
  if (host !== '127.0.0.1') fail('HOLOLAKE_RELEASE_LOOPBACK_BIND_REQUIRED')
  const port = Number(env.HOLOLAKE_RELEASE_PORT || 3940)
  if (!Number.isInteger(port) || port < 1024 || port > 65535) fail('HOLOLAKE_RELEASE_PORT_INVALID')
  const stateRoot = path.resolve(env.HOLOLAKE_RELEASE_STATE_ROOT || '/var/lib/guanghu/hololake-release-broadcast')
  const runtimeState = loadRuntimeState(stateRoot, { enforceRootOwner: env.HOLOLAKE_RELEASE_ENFORCE_ROOT_OWNER === '1' })
  const server = createReleaseServer(runtimeState)
  server.on('clientError', (_error, socket) => socket.end('HTTP/1.1 400 Bad Request\r\nConnection: close\r\n\r\n'))
  server.listen(port, host, () => {
    process.stdout.write(`${JSON.stringify({ schema: 'hololake.release-broadcast-startup/v1', host, port, state: runtimeState.state })}\n`)
  })
  return server
}

if (process.argv[1] && path.resolve(process.argv[1]) === fileURLToPath(import.meta.url)) {
  try {
    main()
  } catch (error) {
    process.stderr.write(`${error instanceof Error ? error.message : String(error)}\n`)
    process.exitCode = 1
  }
}