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) }
function MK([int[]]$cp) { -join ($cp | ForEach-Object { [char]$_ }) }
$zh2  = MK @(0x4E2D, 0x6587)                             # 2 CJK
$zh4  = MK @(0x4E2D, 0x6587, 0x5907, 0x4EFD)             # 4 CJK
$ascii8 = '12345678'
$emoji  = [char]::ConvertFromUtf32(0x1F600)
$box3   = MK @(0x250C, 0x2500, 0x2510)                   # box drawing light
$fullw  = MK @(0xFF21, 0xFF22)                           # fullwidth latin A B
$halfk  = MK @(0xFF71, 0xFF72)                           # halfwidth katakana
L "===== DISPLAY-WIDTH PROBE [$HostLabel] ====="
L ("PSVersion              : " + $PSVersionTable.PSVersion)
L ("PSEdition              : " + $PSVersionTable.PSEdition)
L ("IsOutputRedirected     : " + [Console]::IsOutputRedirected)
L ("Console.OutputEncoding : " + [Console]::OutputEncoding.WebName + " (CP " + [Console]::OutputEncoding.CodePage + ")")
L ("`$OutputEncoding       : " + $OutputEncoding.WebName)
try { L ("Console.WindowWidth    : " + [Console]::WindowWidth) } catch { L ("Console.WindowWidth THREW") }
try { L ("RawUI.WindowSize       : " + $Host.UI.RawUI.WindowSize.Width + 'x' + $Host.UI.RawUI.WindowSize.Height) } catch { L ("RawUI.WindowSize THREW") }
L ""
L "--- .Length / Measure-Object -Character / CODEPOINTS ---"
$cases = @(
  ,@('8 ASCII    ', $ascii8)
  ,@('2 CJK      ', $zh2)
  ,@('4 CJK      ', $zh4)
  ,@('3 boxdraw  ', $box3)
  ,@('1 emoji    ', $emoji)
  ,@('2 fullwidth', $fullw)
  ,@('2 halfkana ', $halfk)
)
foreach ($c in $cases) {
  $nm = $c[0]; $s = $c[1]
  $s = [string]$s
  $cps = ($s.ToCharArray() | ForEach-Object { 'U+{0:X4}' -f [int]$_ }) -join ' '
  L ("  $nm .Length=" + $s.Length + "  Measure-Object-Character=" + (($s | Measure-Object -Character).Characters) + "  cps=[$cps]")
}
L ""
L "--- BUILT-IN DISPLAY-WIDTH FUNCTION? ---"
$found = @()
foreach ($c in (Get-Command -CommandType Cmdlet,Function -ErrorAction SilentlyContinue)) {
  if ($c.Name -match 'Width|Wide') { $found += ($c.Name + '(' + $c.CommandType + '/' + $c.Source + ')') }
}
L ("  commands matching *Width*|*Wide* : " + $(if ($found.Count) { $found -join ', ' } else { 'NONE' }))
L ("  [System.Globalization.StringInfo]::ParseCombiningCharacters(2CJK).Count = " + [System.Globalization.StringInfo]::ParseCombiningCharacters($zh2).Count + " (text elements, not columns)")
L ""
L "--- MEASURED COLUMNS (cursor teleport to column 0 of row 12, write, read CursorLeft) ---"
$skip = $false
try { if ([Console]::IsOutputRedirected) { L "  SKIPPED (redirected)"; $skip = $true } } catch { $skip = $true }
if (-not $skip) {
  $row = 12
  if ([Console]::BufferWidth -lt 40) { $row = 5 }
  $vis = [Console]::CursorVisible
  try { [Console]::CursorVisible = $false } catch {}
  foreach ($c in $cases) {
    $nm = $c[0]; $s = [string]$c[1]
    try {
      [Console]::SetCursorPosition(0, $row)
      [Console]::Write((' ' * 60))
      [Console]::SetCursorPosition(0, $row)
      [Console]::Write($s)
      $col = [Console]::CursorLeft
      L ("  write [$nm] at col 0 -> CursorLeft=" + $col + "   => title column width = " + $col + "  (.Length=" + $s.Length + ")")
    } catch { L ("  write [$nm] THREW: " + $_.Exception.Message) }
  }
  try { [Console]::SetCursorPosition(0, $row); [Console]::Write((' ' * 60)); [Console]::SetCursorPosition(0, $row); [Console]::Write($zh2 + 'X'); [Console]::SetCursorPosition(0, $row + 1) } catch {}
  try { [Console]::CursorVisible = $vis } catch {}
}
[System.IO.File]::WriteAllLines($OutFile, $lines, (New-Object System.Text.UTF8Encoding($false)))
Write-Host ("[width-probe2 {0}] wrote {1}" -f $HostLabel, $OutFile) -ForegroundColor Yellow
if ($WatchSeconds -gt 0) { Start-Sleep -Seconds $WatchSeconds }