$ErrorActionPreference = 'Stop'
$root = Split-Path -Parent $PSScriptRoot
$tempRoot = [System.IO.Path]::GetFullPath((Join-Path $root 'temp'))
$work = Join-Path $tempRoot ('hta-hidden-' + [guid]::NewGuid().ToString('N'))
$hta = Join-Path $work 'MassMailer.hta'
$started = $null
try {
    $null = New-Item -ItemType Directory -Path $work -Force
    Copy-Item -LiteralPath (Join-Path $root 'tools') -Destination (Join-Path $work 'tools') -Recurse
    Copy-Item -LiteralPath (Join-Path $root 'src') -Destination (Join-Path $work 'src') -Recurse
    $null = New-Item -ItemType Directory -Path (Join-Path $work 'templates') -Force
    $app = Get-Content -LiteralPath (Join-Path $root 'MassMailer.hta') -Raw
    $app.Replace('APPLICATIONNAME="MassMailer"', 'APPLICATIONNAME="MassMailerSmoke"') |
        Set-Content -LiteralPath $hta -Encoding UTF8
    $dbPath = Join-Path $work 'data\test.mdb'
    $null = New-Item -ItemType Directory -Path (Split-Path -Parent $dbPath) -Force
    $settings = Get-Content -LiteralPath (Join-Path $root 'config.example.ini') -Raw
    $settings.Replace('DB_PATH=data/MassMailer.mdb', ('DB_PATH=' + $dbPath)) |
        Set-Content -LiteralPath (Join-Path $work 'config.ini') -Encoding UTF8
    $cscript = Join-Path $env:SystemRoot 'SysWOW64\cscript.exe'
    & $cscript //nologo (Join-Path $work 'tools\init-db.vbs') (Join-Path $work 'config.ini')
    if ($LASTEXITCODE -ne 0) { throw 'Isolated MDB initialization failed' }
    $mshta = Join-Path $env:SystemRoot 'SysWOW64\mshta.exe'
    $started = Start-Process -FilePath $mshta -ArgumentList ('"' + $hta + '"') -PassThru -WindowStyle Hidden
    $session = $null
    for ($wait = 0; $wait -lt 30; $wait++) {
        Start-Sleep -Seconds 1
        $matches = @(Get-CimInstance Win32_Process -Filter "Name='mshta.exe'" |
            Where-Object { $_.CommandLine -and $_.CommandLine.IndexOf($hta,
                [StringComparison]::OrdinalIgnoreCase) -ge 0 })
        if ($matches.Count -eq 1) {
            $session = Join-Path $work ('temp\session-' + $matches[0].ProcessId + '.txt')
            if (Test-Path -LiteralPath $session -PathType Leaf) { break }
        }
    }
    if ($matches.Count -ne 1 -or -not (Test-Path -LiteralPath $session -PathType Leaf)) {
        throw 'Isolated HTA did not initialize its hidden dispatcher session'
    }
    Start-Sleep -Seconds 3
    Write-Output 'Isolated HTA startup passed while the main app remained open'
}
finally {
    $matches = @(Get-CimInstance Win32_Process -Filter "Name='mshta.exe'" |
        Where-Object { $_.CommandLine -and $_.CommandLine.IndexOf($hta,
            [StringComparison]::OrdinalIgnoreCase) -ge 0 })
    foreach ($process in $matches) {
        Stop-Process -Id $process.ProcessId -Force -ErrorAction SilentlyContinue
    }
    $resolvedWork = [System.IO.Path]::GetFullPath($work)
    if (-not $resolvedWork.StartsWith($tempRoot + [System.IO.Path]::DirectorySeparatorChar,
        [StringComparison]::OrdinalIgnoreCase)) { throw 'Unsafe isolated test cleanup path' }
    if (Test-Path -LiteralPath $resolvedWork) {
        Remove-Item -LiteralPath $resolvedWork -Recurse -Force
    }
}