param([Parameter(Mandatory=$true)][string]$HostLabel, [Parameter(Mandatory=$true)][string]$OutFile, [int]$WatchSeconds = 2)
$lines = New-Object System.Collections.Generic.List[string]
function L($s) { $lines.Add($s) }
$zh       = [string]::Concat([char]0x4E2D, [char]0x6587)
$zh2      = [string]::Concat([char]0x4E2D, [char]0x6587, [char]0x5907, [char]0x4EFD)
$ascii8   = '12345678'
$emoji    = [string]::Concat([char]::ConvertFromUtf32(0x1F600))
$box      = [string]::Concat([char]0x250C, [char]0x2500, [char]0x2510)
$boxOdd   = [string]::Concat([char]0x250C, [char]0x2502, [char]0x2510)
L "===== Chinese / fullwidth width measurement [$HostLabel] ====="
L ("PSVersion                 : " + $PSVersionTable.PSVersion)
L ("Console.WindowWidth       : " + [Console]::WindowWidth)
L ("Console.BufferWidth       : " + [Console]::BufferWidth)
try { L ("RawUI.WindowSize          : " + $Host.UI.RawUI.WindowSize.Width + 'x' + $Host.UI.RawUI.WindowSize.Height) } catch { L ("RawUI.WindowSize THREW: " + $_.Exception.Message) }
L ("Console.OutputEncoding    : " + [Console]::OutputEncoding.WebName)
L ("IsOutputRedirected        : " + [Console]::IsOutputRedirected)
L ""
L ".Length (CHARACTER COUNT) vs REAL COLUMNS:"
foreach ($item in @(@('ascii 8 chars ', $ascii8), @('Chinese 2 chars', $zh), @('Chinese 4 chars', $zh2), @('box-drawing 3  ', $box), @('emoji 1        ', $emoji))) {
  $name = $item[0]; $s = $item[1]
  $chars = $s.ToCharArray()
  $codes = ($chars | ForEach-Object { 'U+{0:X4}' -f [int]$_ }) -join ' '
  $surr  = if ($s.Length -gt 0) { ($s.ToCharArray() | Where-Object { [int]$_ -ge 0xD800 -and [int]$_ -le 0xDFFF }).Count } else { 0 }
  L ("  $name : .Length=$($s.Length)  UTF16-surrogates=$surr  Measure-Object -Character=$(($s | Measure-Object -Character).Characters)  codeunits=$codes")
}
$ms = [string]::Concat($zh, ':', [System.IO.File]::ReadAllText((Join-Path $env:TEMP 'nowhere.txt')) ) 2>$null
L ""
L "WHICH BUILT-IN CAN MEASURE DISPLAY WIDTH? (probe of plausible names)"
$candidates = @('Get-DisplayWidth','Get-StringWidth','Measure-String','Get-VisualLength','Get-ConsoleStringWidth','Format-WideString','Get-WCWidth','Get-CharWidth','Get-TextWidth','Measure-Text','Get-EastAsianWidth')
foreach ($c in $candidates) {
  $cmd = Get-Command $c -ErrorAction SilentlyContinue
  L ("  Get-Command $c -> " + $(if ($cmd) { $cmd.CommandType.ToString() + ' ' + $cmd.Source } else { 'NOT FOUND' }))
}
L ("  [System.Globalization.StringInfo]::ParseCombiningCharacters('$zh').Count = " + [System.Globalization.StringInfo]::ParseCombiningCharacters($zh).Count + "  (text-element count, NOT width)")
L ("  TextInfo: CurrentCulture = " + [System.Globalization.CultureInfo]::CurrentCulture.Name)
L ("  IsInputRedirected/IsOutputRedirected : " + [Console]::IsInputRedirected + '/' + [Console]::IsOutputRedirected)
L ""
L "CURSOR POSITION TEST (needs a real console; skipped if redirected)"
$skip = $false
try { if ([Console]::IsOutputRedirected) { L "  SKIPPED: stdout is redirected, [Console]::SetCursorPosition would throw 'The handle is invalid'"; $skip = $true } } catch { $skip = $true }
if (-not $skip) {
  try {
    [Console]::CursorVisible = $false
    foreach ($pair in @(@('8 ASCII chars ', $ascii8), @('2 CJK chars   ', $zh), @('4 CJK chars   ', $zh2), @('3 box-drawing ', $box), @('1 emoji       ', $emoji))) {
      $name = $pair[0]; $s = $pair[1]
      [Console]::BufferWidth = [Console]::BufferWidth
      [Console]::SetCursorPosition(0, 10)
      [Console]::Write($s)
      $after = [Console]::CursorLeft
      L ("  write '$name' from column 0 -> CursorLeft = $after   (implied display columns = $after)")
    }
    [Console]::SetCursorPosition(0, 10); [Console]::Write('.' * 40)
    [Console]::SetCursorPosition(0, 10); [Console]::Write($zh); [Console]::Write('X')
    L "  visual check: expect 'ZhongWenX' where X starts at column 4 (2 CJK = 4 columns)"
    [Console]::CursorVisible = $true
  } catch { L ("  CURSOR TEST THREW: " + $_.Exception.Message) }
}
[System.IO.File]::WriteAllLines($OutFile, $lines, (New-Object System.Text.UTF8Encoding($false)))
Write-Host ("[width-probe {0}] done, wrote {1}" -f $HostLabel, $OutFile) -ForegroundColor Yellow
if ($WatchSeconds -gt 0) { Start-Sleep -Seconds $WatchSeconds }