param(
    [Parameter(Mandatory = $true)]
    [ValidateSet("Notifier", "BackupOnLogoff")]
    [string]$Task,

    [string]$TaskFolder = "BakRest"
)

$ErrorActionPreference = "Stop"

$repoRoot = Split-Path -Parent $PSScriptRoot
$pythonExe = (& python -c "import sys; print(sys.executable)").Trim()

if (-not $pythonExe -or -not (Test-Path -LiteralPath $pythonExe)) {
    $pythonCommand = Get-Command python -ErrorAction Stop
    $pythonExe = $pythonCommand.Source
}

if (-not (Test-Path -LiteralPath $pythonExe)) {
    throw "Python executable not found. Run this script from the same shell where 'python' works."
}

if ($Task -eq "Notifier") {
    $taskName = "$TaskFolder\ServerNotifierEvery30Minutes"
    $xmlPath = Join-Path $repoRoot "tasks\BakRestServerNotifierEvery30Minutes.xml"
} else {
    $taskName = "$TaskFolder\BackupOnLogoff"
    $xmlPath = Join-Path $repoRoot "tasks\BakRestBackupOnLogoff.xml"
}

if (-not (Test-Path -LiteralPath $xmlPath)) {
    throw "Task XML not found: $xmlPath"
}

$xml = Get-Content -LiteralPath $xmlPath -Raw
$xml = $xml -replace 'encoding="UTF-8"', 'encoding="UTF-16"'
$xml = $xml -replace '<Command>.*?</Command>', ('<Command>{0}</Command>' -f [System.Security.SecurityElement]::Escape($pythonExe))
$xml = $xml -replace '<WorkingDirectory>.*?</WorkingDirectory>', ('<WorkingDirectory>{0}</WorkingDirectory>' -f [System.Security.SecurityElement]::Escape($repoRoot))

$tempXml = Join-Path $env:TEMP ("bakrest-task-{0}.xml" -f ([Guid]::NewGuid()))
[System.IO.File]::WriteAllText($tempXml, $xml, [System.Text.Encoding]::Unicode)

try {
    schtasks.exe /Create /TN $taskName /XML $tempXml /F
    if ($LASTEXITCODE -ne 0) {
        throw "schtasks failed with exit code $LASTEXITCODE"
    }
    Write-Host "Registered task: $taskName"
    Write-Host "Python: $pythonExe"
    Write-Host "WorkingDirectory: $repoRoot"
} finally {
    Remove-Item -LiteralPath $tempXml -Force -ErrorAction SilentlyContinue
}