$uninstallPaths = @(
    "HKLM:\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall",
    "HKLM:\SOFTWARE\WOW6432Node\Microsoft\Windows\CurrentVersion\Uninstall"
)

Write-Host "=== Checking Veeam version consistency ==="

$veeamProducts = @(
    @{
        Name          = "VBR"
        RegistryPath  = "HKLM:\SOFTWARE\Veeam\Veeam Backup and Replication"
        PathValueName = "CorePath"
        ExeName       = "Veeam.Backup.Manager.exe"
        DisplayName   = "Veeam Backup & Replication Server"
    },
    @{
        Name          = "EM"
        RegistryPath  = "HKLM:\SOFTWARE\Veeam\Veeam Backup Reporting"
        PathValueName = "ServicePath"
        ExeName       = "Veeam.Backup.EnterpriseService.exe"
        DisplayName   = "Veeam Backup Enterprise Manager"
    }
)

function Get-VeeamUninstallKey {
    param (
        [Parameter(Mandatory = $true)]
        [string]$DisplayName
    )

    foreach ($path in $uninstallPaths) {
        $key = Get-ChildItem $path -ErrorAction SilentlyContinue | ForEach-Object {
            $props = Get-ItemProperty $_.PsPath -ErrorAction SilentlyContinue
            if ($props.DisplayName -eq $DisplayName) { $_.PsPath }
        } | Select-Object -First 1

        if ($key) {
            return $key
        }
    }

    return $null
}

function Convert-ToVersionObject {
    param (
        [string]$VersionString
    )

    if (-not $VersionString) {
        return $null
    }

    try {
        return [version]($VersionString -replace '[^\d\.]', '')
    }
    catch {
        return $null
    }
}

$processedCount = 0

foreach ($product in $veeamProducts) {
    Write-Host ""
    Write-Host "=== Processing $($product.DisplayName) ==="

    $installPath = (Get-ItemProperty -Path $product.RegistryPath -Name $product.PathValueName -ErrorAction SilentlyContinue).$($product.PathValueName)
    if (-not $installPath) {
        Write-Host "$($product.Name) not found in registry path $($product.RegistryPath). Skipping." -ForegroundColor Cyan
        continue
    }

    $exePath = Join-Path $installPath $product.ExeName
    if (-not (Test-Path $exePath)) {
        Write-Warning "$($product.ExeName) not found at: $exePath"
        continue
    }

    $newVersion = (Get-Item $exePath).VersionInfo.ProductVersion
    if (-not $newVersion) {
        Write-Warning "Could not determine file version from: $exePath"
        continue
    }

    Write-Host "Detected version from file: $newVersion"

    $veeamUninstallKey = Get-VeeamUninstallKey -DisplayName $product.DisplayName
    if (-not $veeamUninstallKey) {
        Write-Warning "Could not find Uninstall entry for '$($product.DisplayName)'."
        continue
    }

    $currentRegVersion = (Get-ItemProperty -Path $veeamUninstallKey -ErrorAction SilentlyContinue).DisplayVersion
    Write-Host "Registry currently lists version: $currentRegVersion"

    $currentVersionObject = Convert-ToVersionObject -VersionString $currentRegVersion
    $newVersionObject = Convert-ToVersionObject -VersionString $newVersion

    if (-not $currentRegVersion) {
        Write-Host "Registry version is empty. Updating registry..." -ForegroundColor Yellow
        Set-ItemProperty -Path $veeamUninstallKey -Name DisplayVersion -Value $newVersion
        Write-Host "Registry updated successfully at:`n $veeamUninstallKey" -ForegroundColor Green
        $processedCount++
        continue
    }

    if ($currentRegVersion -eq $newVersion) {
        Write-Host "Versions match. No update needed." -ForegroundColor Cyan
        $processedCount++
        continue
    }

    if ($currentVersionObject -and $newVersionObject) {
        if ($newVersionObject -gt $currentVersionObject) {
            Write-Host "Newer version detected ($newVersion > $currentRegVersion). Updating registry..." -ForegroundColor Yellow
            Set-ItemProperty -Path $veeamUninstallKey -Name DisplayVersion -Value $newVersion
            Write-Host "Registry updated successfully at:`n $veeamUninstallKey" -ForegroundColor Green
        }
        else {
            Write-Host "Registry version ($currentRegVersion) is equal or newer. No update needed." -ForegroundColor Cyan
        }
    }
    else {
        Write-Host "Version format could not be compared numerically. Updating registry to file version." -ForegroundColor Yellow
        Set-ItemProperty -Path $veeamUninstallKey -Name DisplayVersion -Value $newVersion
        Write-Host "Registry updated successfully at:`n $veeamUninstallKey" -ForegroundColor Green
    }

    $processedCount++
}

if ($processedCount -eq 0) {
    Write-Warning "No supported Veeam installations were processed."
}

Write-Host "`n=== Completed ==="