function quote(value: string): string {
  return `'${value.replace(/'/g, `'"'"'`)}'`
}

// SSH may forward LANG/LC_* through the user's SendEnv configuration.
// Undefined entries also remove inherited keys when merged by the command runner.
export function remoteShellEnvironment(env: NodeJS.ProcessEnv): NodeJS.ProcessEnv {
  const result = { ...env }
  for (const key of Object.keys(result)) {
    if (key === 'LANGUAGE' || key.startsWith('LC_')) result[key] = undefined
  }
  return { ...result, LANG: 'C', LC_ALL: 'C' }
}

export function remoteShellCommand(command: string): string {
  const script = [
    'selected_locale=C',
    // Probe under C so an inherited, unavailable locale cannot break the probe.
    'available_locales=$(locale -a 2>/dev/null) || available_locales=',
    'for candidate in $available_locales; do',
    '  case "$candidate" in C.utf8|C.UTF-8) selected_locale=$candidate; break ;;',
    '    *utf8|*UTF-8|*utf-8) if [ "$selected_locale" = C ]; then selected_locale=$candidate; fi ;;',
    '  esac',
    'done',
    `exec env LANG="$selected_locale" LC_ALL="$selected_locale" LANGUAGE=C /bin/bash --noprofile --norc -c ${quote(command)}`,
  ].join('\n')
  return `env LANG=C LC_ALL=C LANGUAGE=C /bin/sh -c ${quote(script)}`
}