#!/usr/bin/env node

const PORT_PATTERN = /^(?:[1-9]\d{3,4})$/

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

export function renderFrontDoorSnippet(portValue) {
  const text = String(portValue ?? '')
  if (!PORT_PATTERN.test(text)) fail('HOLOLAKE_RELEASE_FRONT_DOOR_PORT_REQUIRED')
  const port = Number(text)
  if (!Number.isInteger(port) || port < 1024 || port > 65535) fail('HOLOLAKE_RELEASE_FRONT_DOOR_PORT_INVALID')
  return `location = /hololake/releases {
    return 308 /hololake/releases/;
}

location ^~ /hololake/releases/ {
    limit_except GET HEAD { deny all; }
    client_max_body_size 0;
    proxy_pass http://127.0.0.1:${port};
    proxy_http_version 1.1;
    proxy_set_header Host $host;
    proxy_set_header Connection "";
    proxy_set_header Authorization "";
    proxy_set_header Cookie "";
    proxy_set_header X-Forwarded-For "";
    proxy_set_header X-Forwarded-Host "";
    proxy_set_header X-Forwarded-Proto "";
    proxy_pass_request_body off;
    proxy_set_header Content-Length "";
    proxy_connect_timeout 2s;
    proxy_send_timeout 10s;
    proxy_read_timeout 60s;
}
`
}

export function main(argv = process.argv.slice(2)) {
  const portIndex = argv.indexOf('--loopback-port')
  if (portIndex < 0 || portIndex + 1 >= argv.length || argv.length !== 2) {
    fail('HOLOLAKE_RELEASE_FRONT_DOOR_USAGE:--loopback-port PORT')
  }
  process.stdout.write(renderFrontDoorSnippet(argv[portIndex + 1]))
}

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