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

    [string]$CssPath = '',

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

Add-PSSnapin Microsoft.SharePoint.PowerShell -ErrorAction SilentlyContinue | Out-Null

$componentId = '035ba968-6488-4d42-86b3-0470ffcc95b9'
$location = 'ClientSideExtension.ApplicationCustomizer'
$name = 'CustomBranding'
$title = 'Custom Branding'

function Get-CustomBrandingPropertiesJson {
    param(
        [string]$Path
    )

    $config = @{
        cssfiles = @()
        placeholdertop = @{ elements = @() }
        placeholderbottom = @{ elements = @() }
    }

    if ($Path -and $Path.Trim().Length -gt 0) {
        $config.cssfiles += @{ path = $Path.Trim() }
    }

    return ($config | ConvertTo-Json -Depth 10 -Compress)
}

function Remove-WebScopedComponentActions {
    param(
        [Microsoft.SharePoint.SPSite]$CurrentSite,
        [string]$CurrentComponentId,
        [string]$CurrentLocation
    )

    $removedCount = 0

    foreach ($web in $CurrentSite.AllWebs) {
        try {
            $webActions = @($web.UserCustomActions | Where-Object {
                $_.Location -eq $CurrentLocation -and
                $_.ClientSideComponentId -and
                $_.ClientSideComponentId.ToString().ToLower() -eq $CurrentComponentId
            })

            foreach ($webAction in $webActions) {
                $web.UserCustomActions.Delete($webAction.Id)
                $removedCount++
            }

            if ($webActions.Count -gt 0) {
                $web.Update()
            }
        }
        finally {
            $web.Dispose()
        }
    }

    return $removedCount
}

$site = Get-SPSite -Identity $SiteUrl
try {
    $removedWebScopedActions = Remove-WebScopedComponentActions -CurrentSite $site -CurrentComponentId $componentId -CurrentLocation $location

    $existingAction = $site.UserCustomActions | Where-Object {
        $_.Location -eq $location -and $_.ClientSideComponentId -and $_.ClientSideComponentId.ToString().ToLower() -eq $componentId
    } | Select-Object -First 1

    if ($existingAction) {
        $action = $existingAction
        Write-Host 'Aktualisiere vorhandene site-scoped Custom Branding UserCustomAction...' -ForegroundColor Yellow
    }
    else {
        $action = $site.UserCustomActions.Add()
        Write-Host 'Erstelle neue site-scoped Custom Branding UserCustomAction...' -ForegroundColor Yellow
    }

    $action.Name = $name
    $action.Title = $title
    $action.Description = $Description
    $action.Location = $location
    $action.ClientSideComponentId = [Guid]$componentId
    $action.ClientSideComponentProperties = Get-CustomBrandingPropertiesJson -Path $CssPath
    $action.Update()

    Write-Host 'Custom Branding wurde site-scoped registriert.' -ForegroundColor Green
    Write-Host ('Entfernte web-scoped Eintraege: ' + $removedWebScopedActions)
    Write-Host ('Beschreibung: ' + $Description)
    Write-Host ('Properties: ' + $action.ClientSideComponentProperties)
}
finally {
    if ($site) {
        $site.Dispose()
    }
}