param(
    [Parameter(Mandatory = $true)]
    [string]$SiteUrl,

    [string]$TermSetName = '',

    [string]$TermSetId = '',

    [ValidateRange(1, 1440)]
    [int]$CacheMinutes = 15,

    [string]$CacheVersion = '1',

    [ValidateSet('megaMenu', 'flyout')]
    [string]$MenuMode = 'megaMenu',

    [switch]$EnableDebug,

    [string]$Description = 'MSFT-Custom-Solution:MegaMenu'
)

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 'Die SharePoint PowerShell-Komponenten wurden nicht gefunden. Bitte in der SharePoint Management Shell ausfuehren.'
    }
}

$componentId = [Guid]'c0abbffb-355d-4d4e-bd38-9e15fb811506'
$legacyComponentId = [Guid]'abc3361f-bb2d-491f-aba3-cd51c19a299b'
$legacyPropertyName = 'PortalSettings.MegaMenu.Configuration'

if ([string]::IsNullOrWhiteSpace($TermSetId) -and [string]::IsNullOrWhiteSpace($TermSetName)) {
    throw 'Bitte TermSetId oder TermSetName angeben.'
}

$properties = [string](@{
    termSetName = $TermSetName.Trim()
    termSetId = $TermSetId.Trim()
    cacheMinutes = $CacheMinutes
    cacheVersion = $CacheVersion
    menuMode = $MenuMode
    debug = [bool]$EnableDebug.IsPresent
} | ConvertTo-Json -Depth 10 -Compress)

$site = Get-SPSite -Identity $SiteUrl

try {
    @($site.UserCustomActions | Where-Object {
        $_.ClientSideComponentId -eq $componentId -or
        $_.ClientSideComponentId -eq $legacyComponentId
    }) | ForEach-Object {
        Write-Host ('Entferne alte Site-Action: ' + $_.Id)
        $_.Delete()
    }

    try {
        if ($site.RootWeb.AllProperties.ContainsKey($legacyPropertyName)) {
            $site.RootWeb.AllProperties.Remove($legacyPropertyName)
            $site.RootWeb.Update()
            Write-Host ('Alte Property-Bag-Konfiguration entfernt: ' + $legacyPropertyName)
        }
    }
    catch {
        Write-Warning ('Die alte Property-Bag-Konfiguration konnte nicht entfernt werden: ' + $_.Exception.Message)
    }

    foreach ($web in $site.AllWebs) {
        try {
            $webUrl = $web.Url
            $actions = @($web.UserCustomActions | Where-Object {
                $_.ClientSideComponentId -eq $componentId -or
                $_.ClientSideComponentId -eq $legacyComponentId
            })

            foreach ($action in $actions) {
                Write-Host ('Entferne alte Web-Action: ' + $webUrl + ' / ' + $action.Id)
                $action.Delete()
            }
        }
        finally {
            $web.Dispose()
        }
    }
}
finally {
    $site.Dispose()
}

$site = Get-SPSite -Identity $SiteUrl

try {
    $action = $site.UserCustomActions.Add()
    $action.Name = [Guid]::NewGuid().ToString('B')
    $action.Title = 'MegaMenu Application Customizer'
    $action.Description = $Description
    $action.Location = 'ClientSideExtension.ApplicationCustomizer'
    $action.ClientSideComponentId = $componentId
    $action.ClientSideComponentProperties = $properties
    $action.Sequence = 100
    $action.Update()

    Write-Host ''
    Write-Host 'MegaMenu wurde zentral fuer die Site Collection registriert.' -ForegroundColor Green
    Write-Host ('Site Collection: ' + $site.Url)
    Write-Host ('Action-ID: ' + $action.Id)
    Write-Host ('Menu mode: ' + $MenuMode)
    Write-Host ('Properties: ' + $properties)
    Write-Host 'Das MegaMenu-SPFx-Paket muss im App Catalog zentral bereitgestellt sein.' -ForegroundColor Yellow
}
finally {
    $site.Dispose()
}