Rework ADK detection

functions/microwin/Invoke-MicrowinGetIso.ps1

@@ -122,11 +122,17 @@ function Invoke-MicrowinGetIso {
     Set-WinUtilTaskbaritem -state "Indeterminate" -overlay "logo"
     Invoke-MicrowinBusyInfo -action "wip" -message "Checking system requirements..." -interactive $false
 
+    $adkKitsRoot = Microwin-GetKitsRoot -wow64environment $false
+    $adkKitsRoot_WOW64Environ = Microwin-GetKitsRoot -wow64environment $true
+
+    $expectedADKPath = "$($adkKitsRoot)Assessment and Deployment Kit"
+    $expectedADKPath_WOW64Environ = "$($adkKitsRoot_WOW64Environ)Assessment and Deployment Kit"
+
     $oscdimgPath = Join-Path $env:TEMP 'oscdimg.exe'
-    $oscdImgFound = [bool] (Get-Command -ErrorAction Ignore -Type Application oscdimg.exe) -or (Test-Path $oscdimgPath -PathType Leaf)
+    $oscdImgFound = [bool] (Microwin-TestKitsRootPaths -adkKitsRootPath "$expectedADKPath" -adkKitsRootPath_WOW64Environ "$expectedADKPath_WOW64Environ") -or (Test-Path $oscdimgPath -PathType Leaf)
     Write-Host "oscdimg.exe on system: $oscdImgFound"
 
-    if (!$oscdImgFound) {
+    if (-not ($oscdImgFound)) {
         $downloadFromGitHub = $sync.WPFMicrowinDownloadFromGitHub.IsChecked
 
         if (!$downloadFromGitHub) {
@@ -162,6 +168,30 @@ function Invoke-MicrowinGetIso {
                 Write-Host "oscdimg.exe was successfully downloaded from github"
             }
         }
+    } elseif (Microwin-TestKitsRootPaths -adkKitsRootPath "$expectedADKPath" -adkKitsRootPath_WOW64Environ "$expectedADKPath_WOW64Environ") {
+        # We have to guess where oscdimg is. We'll check both values...
+        $peToolsPath = ""
+
+        if ($expectedADKPath -ne "Assessment and Deployment Kit") { $peToolsPath = $expectedADKPath }
+        if (($peToolsPath -eq "") -and ($expectedADKPath_WOW64Environ -ne "Assessment and Deployment Kit")) { $peToolsPath = $expectedADKPath_WOW64Environ }
+
+        Write-Host "Using $peToolsPath as the Preinstallation Environment tools path..."
+        # Paths change depending on platform
+        if ([Environment]::Is64BitOperatingSystem) {
+            $oscdimgPath = "$peToolsPath\Deployment Tools\amd64\Oscdimg\oscdimg.exe"
+        } else {
+            $oscdimgPath = "$peToolsPath\Deployment Tools\x86\Oscdimg\oscdimg.exe"
+        }
+
+        # If it's a non-existent file, we won't continue.
+        if (-not (Test-Path -Path "$oscdimgPath" -PathType Leaf)) {
+            $oscdimgFound = $false
+        }
+    }
+
+    if (-not ($oscdimgFound)) {
+        [System.Windows.MessageBox]::Show("oscdimg.exe is not found on the system. Cannot continue.")
+        return
     }
 
     Invoke-MicrowinBusyInfo -action "wip" -message "Checking disk space..." -interactive $false

functions/microwin/Microwin-GetKitsRoot.ps1

@@ -0,0 +1,40 @@
+function Microwin-GetKitsRoot {
+    <#
+        .SYNOPSIS
+            Gets the kits root path for the Windows Assessment and Deployment Kit (ADK)
+        .PARAMETER wow64environment
+            Determines whether to search in a WOW64 compatibility environment (HKLM\SOFTWARE\WOW6432Node)
+        .OUTPUTS
+            The path to the kits root
+    #>
+
+    param (
+        [Parameter(Mandatory = $true, Position = 0)] [bool]$wow64environment
+    )
+
+    $adk10KitsRoot = ""
+
+    # if we set the wow64 bit on and we're on a 32-bit system, then we prematurely return the value
+    if (($wow64environment -eq $true) -and (-not [Environment]::Is64BitOperatingSystem)) {
+        return $adk10KitsRoot
+    }
+
+    $regPath = ""
+    if ($wow64environment) {
+        $regPath = "HKLM:\SOFTWARE\WOW6432Node\Microsoft\Windows Kits\Installed Roots"
+    } else {
+        $regPath = "HKLM:\SOFTWARE\Microsoft\Windows Kits\Installed Roots"
+    }
+
+    if ((Test-Path "$regPath") -eq $false) {
+        return $adk10KitsRoot
+    }
+
+    try {
+        $adk10KitsRoot = Get-ItemPropertyValue -Path $regPath -Name "KitsRoot10" -ErrorAction Stop
+    } catch {
+        Write-Host "Could not find ADK."
+    }
+
+    return $adk10KitsRoot
+}

functions/microwin/Microwin-TestKitsRootPaths.ps1

@@ -0,0 +1,11 @@
+function Microwin-TestKitsRootPaths {
+    param (
+        [Parameter(Mandatory = $true, Position = 0)] [string]$adkKitsRootPath,
+        [Parameter(Mandatory = $true, Position = 1)] [string]$adkKitsRootPath_WOW64Environ
+    )
+
+    if (Test-Path "$adkKitsRootPath") { return $true }
+    if (Test-Path "$adkKitsRootPath_WOW64Environ") { return $true }
+
+    return $false
+}