<#
.SYNOPSIS
    Finds AD users based on UVHD (User Profile Disk) file names.

.DESCRIPTION
    Scans a folder of UVHD disks, extracts the SID from each file name
    (format UVHD-S-1-5-21-*.vhdx), and looks up the matching user in AD.

.PARAMETER UVHDPath
    Path to the folder containing the UVHD files.

.PARAMETER ExportCsv
    Optional path to export the results to a CSV file.

.EXAMPLE
    .\Get-RDSUsersFromUVHD.ps1 -UVHDPath "\\fileserver\UPD$"

.EXAMPLE
    .\Get-RDSUsersFromUVHD.ps1 -UVHDPath "D:\UPD" -ExportCsv "C:\Temp\uvhd_users.csv"

.NOTES
    Author:   Petr Štěpán
    Created:  2026-07-21
    Version:  1.0.0
    Changelog:
        1.0.0 - Initial version
#>

#Requires -Modules ActiveDirectory
[CmdletBinding(SupportsShouldProcess = $true, ConfirmImpact = 'Low')]
param (
    [Parameter(Mandatory = $true)]
    [ValidateNotNullOrEmpty()]
    [string]
    $UVHDPath,

    [Parameter(Mandatory = $false)]
    [ValidateNotNullOrEmpty()]
    [string]
    $ExportCsv
)

Set-StrictMode -Version Latest
$ErrorActionPreference = 'Stop'

Write-Verbose "Loading UVHD files from '$UVHDPath'..."
try {
    $vhdxFiles = @(Get-ChildItem -Path $UVHDPath -Filter "UVHD-S-1-5-21-*.vhdx" -File -ErrorAction Stop)
}
catch {
    Write-Error "Failed to read folder '$UVHDPath': $_"
    exit 1
}

if ($vhdxFiles.Count -eq 0) {
    Write-Warning "No UVHD files were found in folder '$UVHDPath'."
    exit 0
}

Write-Host "Found $($vhdxFiles.Count) UVHD files. Looking up users in AD...`n" -ForegroundColor Cyan

$results = @(foreach ($file in $vhdxFiles) {
    # Extract the SID from the file name: UVHD-S-1-5-21-xxx-xxx-xxx-xxxx.vhdx
    $sidString = $file.BaseName -replace '^UVHD-', ''

    $adUser = $null
    $status = $null

    try {
        $sid    = [System.Security.Principal.SecurityIdentifier]::new($sidString)
        $adUser = Get-ADUser -Identity $sid -Properties DisplayName, EmailAddress, Enabled, DistinguishedName -ErrorAction Stop
        $status = "OK"
    }
    catch [Microsoft.ActiveDirectory.Management.ADIdentityNotFoundException] {
        $status = "User not found in AD"
    }
    catch {
        $status = "Error: $($_.Exception.Message)"
    }

    [PSCustomObject]@{
        File              = $file.Name
        SID               = $sidString
        SamAccountName    = $adUser.SamAccountName
        DisplayName       = $adUser.DisplayName
        Email             = $adUser.EmailAddress
        Enabled           = $adUser.Enabled
        DistinguishedName = $adUser.DistinguishedName
        SizeMB            = [math]::Round($file.Length / 1MB, 0)
        LastModified      = $file.LastWriteTime
        Status            = $status
    }
})

# Console output
$results | Format-Table -AutoSize File, SamAccountName, DisplayName, Enabled, SizeMB, LastModified, Status

# Summary
$ok      = @($results | Where-Object { $_.Status -eq "OK" }).Count
$missing = @($results | Where-Object { $_.Status -ne "OK" }).Count

Write-Host "`nSummary:" -ForegroundColor Cyan
Write-Host "  Found in AD : $ok" -ForegroundColor Green
Write-Host "  Not found   : $missing" -ForegroundColor $(if ($missing -gt 0) { "Yellow" } else { "Green" })

# Optional CSV export
if ($ExportCsv) {
    if ($PSCmdlet.ShouldProcess($ExportCsv, "Export $($results.Count) records to CSV")) {
        $results | Export-Csv -Path $ExportCsv -NoTypeInformation -Encoding UTF8
        Write-Host "`nResults exported to: $ExportCsv" -ForegroundColor Cyan
    }
}

exit 0