Add-Type -AssemblyName System.Windows.Forms

$SetFTAPath = "C:\ProgramData\SetUserFTA\SetUserFTA.exe"

# Prepare form early so we can use it as a message box owner
$form = New-Object System.Windows.Forms.Form
$form.Text = "Set Default PDF Application"
$form.Size = New-Object System.Drawing.Size(400, 250)
$form.StartPosition = "CenterScreen"
$form.TopMost = $true

# Check if SetUserFTA.exe exists
if (-not (Test-Path $SetFTAPath)) {
    [System.Windows.Forms.MessageBox]::Show($form, "SetUserFTA.exe not found.`nExpected at:`n$SetFTAPath", "Missing Dependency", [System.Windows.Forms.MessageBoxButtons]::OK, [System.Windows.Forms.MessageBoxIcon]::Error)
    $form.Close()
    return
}

# Known ProgIDs and Friendly Names
$friendlyMap = @{
    "AcroExch.Document.DC" = "Adobe Acrobat"
    "AcroExch.Document"    = "Adobe Reader"
    "NitroPDF.Pro.v13"     = "Nitro PDF Pro 13"
    "NitroPDF.Pro.v14"     = "Nitro PDF Pro 14"
    "Bluebeam.Revu.PDF"    = "Bluebeam Revu"
    "RedlinePDFfile"       = "Bluebeam Revu PDF"
    "MSEdgePDF"            = "Microsoft Edge"
}

# Check if a ProgID exists in the registry
function Is-ProgIDPresent($progId) {
    $paths = @(
        "HKCR:\$progId",
        "HKCU:\Software\Classes\$progId",
        "HKLM:\Software\Classes\$progId"
    )
    foreach ($path in $paths) {
        if (Test-Path $path) { return $true }
    }
    return $false
}

# Get only installed PDF handlers
function Get-InstalledPDFProgIDs {
    $installed = @()
    foreach ($progId in $friendlyMap.Keys) {
        if (Is-ProgIDPresent $progId) {
            $installed += $progId
        }
    }
    return $installed
}

# Get current default handler
function Get-CurrentPDFHandler {
    try {
        $userSID = ([System.Security.Principal.WindowsIdentity]::GetCurrent()).User.Value
        $keyPath = "Registry::HKEY_USERS\$userSID\Software\Microsoft\Windows\CurrentVersion\Explorer\FileExts\.pdf\UserChoice"
        if (Test-Path $keyPath) {
            return (Get-ItemProperty -Path $keyPath -Name ProgId).ProgId
        } else {
            return "Unknown"
        }
    } catch {
        return "Error"
    }
}

# Set PDF default using SetUserFTA with a mapping file
function Set-PDFDefaultHandler($progId) {
    try {
        $mapFile = Join-Path $env:TEMP "SetFTA.txt"
        "pdf $progId" | Out-File -FilePath $mapFile -Encoding ASCII -Force
        Start-Process -FilePath $SetFTAPath -ArgumentList "`"$mapFile`"" -Wait -NoNewWindow
    } catch {
        [System.Windows.Forms.MessageBox]::Show($form, "Failed to apply default:`n$_", "Error", [System.Windows.Forms.MessageBoxButtons]::OK, [System.Windows.Forms.MessageBoxIcon]::Error)
    }
}

# Add controls
$labelCurrent = New-Object System.Windows.Forms.Label
$labelCurrent.Text = "Current Default Handler:"
$labelCurrent.Location = New-Object System.Drawing.Point(20, 20)
$labelCurrent.AutoSize = $true
$form.Controls.Add($labelCurrent)

$labelCurrentValue = New-Object System.Windows.Forms.Label
$labelCurrentValue.Text = Get-CurrentPDFHandler
$labelCurrentValue.Location = New-Object System.Drawing.Point(180, 20)
$labelCurrentValue.AutoSize = $true
$form.Controls.Add($labelCurrentValue)

$comboBox = New-Object System.Windows.Forms.ComboBox
$comboBox.Location = New-Object System.Drawing.Point(20, 60)
$comboBox.Size = New-Object System.Drawing.Size(340, 20)
$comboBox.DropDownStyle = "DropDownList"
$form.Controls.Add($comboBox)

# Build dropdown from installed handlers
$displayToProgID = @{}
$installedProgIDs = Get-InstalledPDFProgIDs
$currentHandler = Get-CurrentPDFHandler

foreach ($progId in $installedProgIDs) {
    $friendlyName = $friendlyMap[$progId]
    if (-not $friendlyName) { $friendlyName = $progId }
    $displayToProgID[$friendlyName] = $progId
    $comboBox.Items.Add($friendlyName)

    if ($progId -eq $currentHandler) {
        $comboBox.SelectedItem = $friendlyName
    }
}

# Apply Button
$buttonApply = New-Object System.Windows.Forms.Button
$buttonApply.Text = "Set as Default"
$buttonApply.Location = New-Object System.Drawing.Point(20, 100)
$buttonApply.Size = New-Object System.Drawing.Size(120, 30)
$buttonApply.Add_Click({
    if ($comboBox.SelectedItem -and $comboBox.Enabled) {
        $selectedDisplayName = $comboBox.SelectedItem
        $selectedProgId = $displayToProgID[$selectedDisplayName]
        Set-PDFDefaultHandler $selectedProgId
        [System.Windows.Forms.MessageBox]::Show($form, "Default PDF app set to: $selectedDisplayName", "Success", [System.Windows.Forms.MessageBoxButtons]::OK, [System.Windows.Forms.MessageBoxIcon]::Information)
        $labelCurrentValue.Text = Get-CurrentPDFHandler
    } else {
        [System.Windows.Forms.MessageBox]::Show($form, "Please select an application.", "Error", [System.Windows.Forms.MessageBoxButtons]::OK, [System.Windows.Forms.MessageBoxIcon]::Error)
    }
})
$form.Controls.Add($buttonApply)

# Close Button
$buttonClose = New-Object System.Windows.Forms.Button
$buttonClose.Text = "Close"
$buttonClose.Location = New-Object System.Drawing.Point(240, 100)
$buttonClose.Size = New-Object System.Drawing.Size(120, 30)
$buttonClose.Add_Click({ $form.Close() })
$form.Controls.Add($buttonClose)

# Show GUI
[void]$form.ShowDialog()