/* eslint-disable no-undef */

"use strict";

/**
 * Windows PowerShell command helpers for remote SSH hosts.
 *
 * Every script is UTF-16LE Base64-encoded and invoked via
 *   powershell -NoProfile -NonInteractive -EncodedCommand <blob>
 * so cmd.exe / OpenSSH-Server quoting cannot break it.
 */

/**
 * Encode a PowerShell script string as UTF-16LE bytes, then Base64.
 * Matches what `powershell -EncodedCommand` expects.
 */
function encodePowerShellScript(script) {
  if (typeof Buffer !== "undefined" && Buffer.alloc) {
    // Node Buffer path: convert UTF-8 → UTF-16LE → Base64.
    const utf8 = Buffer.from(String(script), "utf8");
    const utf16 = Buffer.alloc(utf8.length * 2);
    for (let i = 0; i < utf8.length; i++) {
      utf16[i * 2] = utf8[i];       // low byte (ASCII chars: high byte = 0)
      utf16[i * 2 + 1] = 0;         // high byte
    }
    return utf16.toString("base64");
  }
  // Browser / pure JS fallback.
  const chars = String(script);
  let out = "";
  for (let i = 0; i < chars.length; i++) {
    const code = chars.charCodeAt(i);
    out += String.fromCharCode(code & 0xff, (code >> 8) & 0xff);
  }
  return btoa(out);
}

/** Build an SSH-exec-friendly PowerShell invocation. */
function wrapPowerShell(encodedBlob) {
  return `powershell -NoProfile -NonInteractive -EncodedCommand ${encodedBlob}`;
}

// ---------------------------------------------------------------------------
// Process list
// ---------------------------------------------------------------------------

const PROCESS_LIST_PS = [
  // Minimal Windows process list — speed > precision.
  // Single Get-Process pass; CPU% is a rough estimate (cumulative/uptime/cores).
  // PPID and command line come from Win32_Process (one WMI query, indexed).
  '$ErrorActionPreference = "SilentlyContinue";',
  '$procs = Get-Process;',
  // Build WMI lookup for PPID + command line
  '$wmi = @{};',
  'Get-CimInstance Win32_Process | ForEach-Object { $wmi[[int]$_.ProcessId] = $_ };',
  // Get logical core count from first processor (faster than ComputerSystem WMI)
  '$cores = (Get-CimInstance Win32_Processor | Measure-Object -Property NumberOfLogicalProcessors -Sum).Sum;',
  'if (-not $cores -or $cores -le 0) { $cores = 1 };',
  '$totalMemMB = [math]::Round((Get-CimInstance Win32_ComputerSystem).TotalPhysicalMemory / 1MB, 0);',
  '$now = Get-Date;',
  '$rows = foreach ($p in $procs) {',
  '  $cpu = 0;',
  '  if ($p.CPU -ne $null -and $p.StartTime -ne $null) {',
  '    $up = ($now - $p.StartTime).TotalSeconds;',
  '    if ($up -gt 0) { $cpu = [math]::Round([double]$p.CPU / $up / $cores * 100, 2) };',
  '    if ($cpu -lt 0) { $cpu = 0 };',
  '    if ($cpu -gt 100) { $cpu = 100 };',
  '  }',
  '  $w = $wmi[$p.Id];',
  '  $ppid = if ($w) { [int]$w.ParentProcessId } else { 0 };',
  '  $cmd = if ($w -and $w.CommandLine) { $w.CommandLine } else { $p.ProcessName };',
  '  $el = "";',
  '  if ($p.StartTime) {',
  '    $e = $now - $p.StartTime;',
  '    $el = "{0}:{1}:{2}" -f [int]$e.TotalHours, $e.Minutes, $e.Seconds;',
  '  };',
  '  $wsKb = [math]::Round($p.WorkingSet64 / 1024, 0);',
  '  $mem = if ($totalMemMB -gt 0) { [math]::Round($wsKb / 1024 / $totalMemMB * 100, 2) } else { 0 };',
  '  [PSCustomObject]@{',
  '    ProcessId = $p.Id;',
  '    ParentProcessId = $ppid;',
  '    Name = $p.ProcessName;',
  '    CpuPercent = $cpu;',
  '    MemPercent = $mem;',
  '    WorkingSetKb = $wsKb;',
  '    Elapsed = $el;',
  '    CommandLine = $cmd;',
  '  }',
  '}',
  '$rows | Sort-Object WorkingSetKb -Descending | Select-Object -First 200 | ConvertTo-Json -Compress',
].join(" ");

const PROCESS_LIST_PS_COMMAND = wrapPowerShell(encodePowerShellScript(PROCESS_LIST_PS));

// ---------------------------------------------------------------------------
// Port list
// ---------------------------------------------------------------------------

// portOps.cjs already defines LISTEN_PORTS_WINDOWS inline; export it here too
// so other ops can re-use the encoding convention.
const PORT_LIST_PS_INNER = [
  '$rows = @();',
  '$rows += @(Get-NetTCPConnection -State Listen -ErrorAction SilentlyContinue | ',
  "Select-Object LocalAddress,LocalPort,OwningProcess,@{Name='Protocol';Expression={'tcp'}});",
  '$rows += @(Get-NetUDPEndpoint -ErrorAction SilentlyContinue | Where-Object { ',
  '$a = [string]$_.LocalAddress; ',
  '$wildcard = ($a -eq "0.0.0.0" -or $a -eq "::" -or $a -eq "*"); ',
  '$loopback = ($a -eq "127.0.0.1" -or $a -eq "::1"); ',
  'if ($wildcard -or $loopback) { $true } else { $_.LocalPort -lt 49152 } ',
  "} | Select-Object LocalAddress,LocalPort,OwningProcess,@{Name='Protocol';Expression={'udp'}}); ",
  "if ($rows.Count -gt 0) { $rows | ConvertTo-Json -Compress } else { '[]' }",
].join("");

const PORT_LIST_PS_COMMAND = wrapPowerShell(encodePowerShellScript(PORT_LIST_PS_INNER));

// ---------------------------------------------------------------------------
// Service list
// ---------------------------------------------------------------------------

const SERVICE_LIST_PS_INNER = [
  // Force UTF-8 output so Chinese service names don't get mangled over SSH.
  '[Console]::OutputEncoding = [System.Text.Encoding]::UTF8;',
  '$OutputEncoding = [System.Text.Encoding]::UTF8;',
  '$services = Get-Service -ErrorAction SilentlyContinue | ForEach-Object {',
  '  [PSCustomObject]@{',
  '    Name = $_.Name;',
  '    DisplayName = $_.DisplayName;',
  '    Status = $_.Status.ToString();',
  '    StartType = $_.StartType.ToString();',
  '  }',
  '};',
  '$services | ConvertTo-Json -Compress',
].join(" ");

const SERVICE_LIST_PS_COMMAND = wrapPowerShell(encodePowerShellScript(SERVICE_LIST_PS_INNER));

// ---------------------------------------------------------------------------
// Capability probe (mirrors CAPABILITY_SCRIPT_POSIX marker format)
// ---------------------------------------------------------------------------

const CAPABILITY_PROBE_PS_INNER = [
  '$ErrorActionPreference = "SilentlyContinue";',
  'Write-Output "__NC_OS__=Windows";',
  'if (Get-Command tmux -ErrorAction SilentlyContinue) { Write-Output "__NC_TMUX__=1" };',
  'if (Get-Command docker -ErrorAction SilentlyContinue) { Write-Output "__NC_DOCKER__=1" };',
  'if (Get-Command nvidia-smi -ErrorAction SilentlyContinue) { Write-Output "__NC_NVIDIA_SMI__=1" };',
  'if (Get-Command npu-smi -ErrorAction SilentlyContinue) { Write-Output "__NC_NPU_SMI__=1" };',
  'if (Get-Command ss -ErrorAction SilentlyContinue) { Write-Output "__NC_SS__=1" };',
  // Windows always has netstat.exe
  'Write-Output "__NC_NETSTAT__=1";',
  'if (Get-Command lsof -ErrorAction SilentlyContinue) { Write-Output "__NC_LSOF__=1" };',
  // Windows has system services via Get-Service — treat as "systemctl-equivalent"
  'Write-Output "__NC_SYSTEMCTL__=1";',
].join(" ");

const CAPABILITY_PROBE_PS_COMMAND = wrapPowerShell(encodePowerShellScript(CAPABILITY_PROBE_PS_INNER));

// ---------------------------------------------------------------------------
// Service action helper
// ---------------------------------------------------------------------------

function buildServiceActionPsCommand(action, serviceName) {
  const safe = String(serviceName).replace(/[^a-zA-Z0-9_\\-]/g, "").slice(0, 256);
  if (!safe) return null;
  let verb;
  switch (action) {
    case "start":   verb = "Start-Service";   break;
    case "stop":    verb = "Stop-Service";    break;
    case "restart": verb = "Restart-Service"; break;
    default: return null;
  }
  const script = `${verb} -Name "${safe}" -ErrorAction Stop; Write-Output "__NC_OK__"`;
  return wrapPowerShell(encodePowerShellScript(script));
}

// ---------------------------------------------------------------------------
// Process kill
// ---------------------------------------------------------------------------

function buildStopProcessPsCommand(pid, force) {
  const p = Math.trunc(Number(pid));
  if (!Number.isFinite(p) || p <= 0) return null;
  const cmd = force
    ? `Stop-Process -Id ${p} -Force -ErrorAction Stop; Write-Output "__NC_OK__"`
    : `Stop-Process -Id ${p} -ErrorAction Stop; Write-Output "__NC_OK__"`;
  return wrapPowerShell(encodePowerShellScript(cmd));
}

module.exports = {
  encodePowerShellScript,
  wrapPowerShell,
  PROCESS_LIST_PS_COMMAND,
  PORT_LIST_PS_COMMAND,
  SERVICE_LIST_PS_COMMAND,
  CAPABILITY_PROBE_PS_COMMAND,
  buildServiceActionPsCommand,
  buildStopProcessPsCommand,
};