param(
    [Parameter(Mandatory = $true)][string]$SiteUrl,
    [Parameter(Mandatory = $true)][string]$TermSetId,
    [int]$CacheMinutes = 15,
    [string]$CacheVersion = '1',
    [ValidateRange(1, 8)][int]$MaxDepth = 3,
    [switch]$ShowRoot,
    [switch]$EnableDebug
)

if (-not (Get-Command -Name Get-SPSite -ErrorAction SilentlyContinue)) {
    if (Get-Module -ListAvailable -Name Microsoft.SharePoint.PowerShell) {
        Import-Module Microsoft.SharePoint.PowerShell -DisableNameChecking
    } elseif (Get-PSSnapin -Registered -Name Microsoft.SharePoint.PowerShell -ErrorAction SilentlyContinue) {
        Add-PSSnapin Microsoft.SharePoint.PowerShell
    } else { throw 'Bitte in der SharePoint Management Shell ausführen.' }
}

$componentId = [Guid]'e37b828f-4315-461a-b1b0-fcf991deda3d'
$parsedTermSetId = [Guid]::Empty
if (-not [Guid]::TryParse($TermSetId, [ref]$parsedTermSetId)) { throw 'TermSetId ist keine gültige GUID.' }
$properties = @{
    schemaVersion = 1
    portalSettings = @{ providerKey = 'currentnavigation'; contractVersion = 1; minimumPortalSettingsVersion = '3.1.0' }
    termSetId = $parsedTermSetId.ToString()
    termSetName = ''
    cacheMinutes = [Math]::Min([Math]::Max($CacheMinutes, 1), 1440)
    cacheVersion = $(if ([string]::IsNullOrWhiteSpace($CacheVersion)) { '1' } else { $CacheVersion.Trim() })
    maxDepth = $MaxDepth
    showRoot = [bool]$ShowRoot.IsPresent
    debug = [bool]$EnableDebug.IsPresent
}

$site = Get-SPSite -Identity $SiteUrl
try {
    $actions = @($site.UserCustomActions | Where-Object {
        $_.Location -eq 'ClientSideExtension.ApplicationCustomizer' -and $_.ClientSideComponentId -eq $componentId
    })
    $action = $actions | Select-Object -First 1
    if (-not $action) { $action = $site.UserCustomActions.Add() }
    $action.Name = 'CurrentNavigation'
    $action.Title = 'Current Navigation Application Customizer'
    $action.Description = 'MSFT-Custom-Solution:CurrentNavigation'
    $action.Location = 'ClientSideExtension.ApplicationCustomizer'
    $action.Sequence = 110
    $action.ClientSideComponentId = $componentId
    $action.ClientSideComponentProperties = $properties | ConvertTo-Json -Depth 10 -Compress
    $action.Update()
    @($actions | Select-Object -Skip 1) | ForEach-Object { $_.Delete() }
    foreach ($web in $site.AllWebs) {
        try {
            @($web.UserCustomActions | Where-Object {
                $_.Location -eq 'ClientSideExtension.ApplicationCustomizer' -and $_.ClientSideComponentId -eq $componentId
            }) | ForEach-Object { $_.Delete() }
        } finally { $web.Dispose() }
    }
    Write-Host 'CurrentNavigation wurde für die Site Collection registriert.' -ForegroundColor Green
} finally { if ($site) { $site.Dispose() } }