"use strict";

const { encodedCommand, parseWindowsOutput } = require("./windowsPrivilegedExec");

// Detects the remote operating system from system facts, never from prompts or host names.
// 1) "uname -s" identifies POSIX systems (Linux, BSD, macOS).
// 2) Otherwise a self-contained encoded PowerShell command reads the Windows version (registry, plus
//    Win32_OperatingSystem when WMI is permitted) and the OpenSSH DefaultShell registry value; it works whether
//    the default shell is cmd.exe, powershell.exe or pwsh.
const POSIX_KERNELS = /^(Linux|Darwin|FreeBSD|OpenBSD|NetBSD|DragonFly|SunOS|AIX)\b/;
const WINDOWS_PROBE = String.raw`$ProgressPreference='SilentlyContinue'
try {
  # Registry first: standard accounts on an SSH network logon are usually denied WMI/CIM access.
  $nt = Get-ItemProperty 'HKLM:\SOFTWARE\Microsoft\Windows NT\CurrentVersion' -ErrorAction SilentlyContinue
  $shell = (Get-ItemProperty 'HKLM:\SOFTWARE\OpenSSH' -ErrorAction SilentlyContinue).DefaultShell
  $caption = [string]$nt.ProductName; $build = [string]$nt.CurrentBuildNumber
  if ($caption -match '^Windows 10' -and [int]("0$build") -ge 22000) { $caption = $caption -replace '^Windows 10', 'Windows 11' }
  $type = [string](Get-ItemProperty 'HKLM:\SYSTEM\CurrentControlSet\Control\ProductOptions' -ErrorAction SilentlyContinue).ProductType
  $productType = @{ 'WinNT' = 1; 'LanmanNT' = 2; 'ServerNT' = 3 }[$type]
  $version = [Environment]::OSVersion.Version.ToString()
  try { $os = Get-CimInstance Win32_OperatingSystem -ErrorAction Stop; $caption = $os.Caption; $version = $os.Version; $productType = [int]$os.ProductType } catch {}
  $value = [ordered]@{ caption = $caption; version = $version; build = $build; productType = $productType
    installationType = [string]$nt.InstallationType; defaultShell = [string]$shell; psVersion = $PSVersionTable.PSVersion.ToString()
    is64BitProcess = [Environment]::Is64BitProcess; languageMode = [string]$ExecutionContext.SessionState.LanguageMode
    localAccounts = [bool](Get-Command Get-LocalUser -ErrorAction SilentlyContinue); pwsh = [string](Get-Command pwsh.exe -ErrorAction SilentlyContinue).Source }
  [Console]::Out.WriteLine('CHJ_RESULT:' + [Convert]::ToBase64String([Text.Encoding]::UTF8.GetBytes(($value | ConvertTo-Json -Compress))))
} catch { [Console]::Out.WriteLine('CHJ_ERR:PLATFORM_PROBE_FAILED:' + [Convert]::ToBase64String([Text.Encoding]::UTF8.GetBytes($_.Exception.Message))) }`;

function shellName(defaultShell) {
  const value = String(defaultShell || "").toLowerCase();
  if (!value) return "cmd.exe";
  if (/pwsh(\.exe)?$/.test(value)) return "pwsh";
  if (/powershell(\.exe)?$/.test(value)) return "powershell";
  if (/cmd(\.exe)?$/.test(value)) return "cmd.exe";
  if (/bash(\.exe)?$/.test(value)) return "bash";
  return value.split(/[\\/]/).pop();
}

async function detectPlatform(sessionManager, sessionId, { refresh = false } = {}) {
  const record = sessionManager._requireConnected(sessionId);
  if (record.platform && !refresh) return record.platform;
  const uname = await sessionManager._execStream(record, "uname -s", { timeoutMs: 15000 }).done.catch(() => null);
  const kernel = String(uname?.stdout || "").trim().split(/\r?\n/)[0] || "";
  if (uname?.code === 0 && POSIX_KERNELS.test(kernel)) {
    record.platform = { os: kernel.startsWith("Linux") ? "linux" : "posix", kernel, detectedBy: "uname" };
    return record.platform;
  }
  const probe = await sessionManager._execStream(record, encodedCommand(WINDOWS_PROBE), { timeoutMs: 60000 }).done;
  let info;
  try { info = parseWindowsOutput(probe.stdout, probe.stderr, probe.code, "PLATFORM_"); }
  catch (error) {
    record.platform = { os: "unknown", kernel, detectedBy: "none", reason: error.message };
    return record.platform;
  }
  record.platform = {
    os: "windows",
    detectedBy: "Win32_OperatingSystem",
    caption: String(info.caption || ""),
    version: String(info.version || ""),
    build: String(info.build || ""),
    server: Number(info.productType) !== 1,
    serverCore: /server core/i.test(String(info.installationType || "")),
    installationType: String(info.installationType || ""),
    defaultShell: shellName(info.defaultShell),
    defaultShellPath: String(info.defaultShell || ""),
    powershell: String(info.psVersion || ""),
    is64BitProcess: info.is64BitProcess === true,
    languageMode: String(info.languageMode || ""),
    localAccounts: info.localAccounts === true,
    pwsh: String(info.pwsh || ""),
    unameOutput: kernel
  };
  return record.platform;
}

module.exports = { WINDOWS_PROBE, detectPlatform, shellName };