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

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

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

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

$site = Get-SPSite -Identity $SiteUrl

try {
    $rootWeb = $site.RootWeb
    $properties = [string]$rootWeb.AllProperties[$configurationProperty]

    if ([string]::IsNullOrWhiteSpace($properties)) {
        $existingAction = $null

        foreach ($web in $site.AllWebs) {
            try {
                $existingAction = @(
                    $web.UserCustomActions |
                        Where-Object {
                            $_.ClientSideComponentId -eq $componentId -or
                            $_.ClientSideComponentId -eq $legacyComponentId
                        }
                ) | Select-Object -First 1

                if ($existingAction) {
                    $properties = [string]$existingAction.ClientSideComponentProperties
                    break
                }
            }
            finally {
                $web.Dispose()
            }
        }
    }

    if ([string]::IsNullOrWhiteSpace($properties)) {
        throw ('Keine MegaMenu-Konfiguration im Property Bag oder in einer bestehenden ' +
            'Web-Registrierung gefunden. Bitte zuerst add-megamenu.ps1 ausfuehren.')
    }

    try {
        $null = $properties | ConvertFrom-Json
    }
    catch {
        throw ('Die gefundene MegaMenu-Konfiguration ist kein gueltiges JSON: ' + $_.Exception.Message)
    }

    $removedSiteActions = 0
    @(
        $site.UserCustomActions |
            Where-Object {
                $_.ClientSideComponentId -eq $componentId -or
                $_.ClientSideComponentId -eq $legacyComponentId
            }
    ) | ForEach-Object {
        $_.Delete()
        $removedSiteActions++
    }

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

    $removedWebActions = 0
    $testedWebUrls = @()

    foreach ($web in $site.AllWebs) {
        try {
            $testedWebUrls += $web.Url

            @(
                $web.UserCustomActions |
                    Where-Object {
                        $_.ClientSideComponentId -eq $componentId -or
                        $_.ClientSideComponentId -eq $legacyComponentId
                    }
            ) | ForEach-Object {
                $_.Delete()
                $removedWebActions++
            }
        }
        finally {
            $web.Dispose()
        }
    }

    $verification = @(
        $site.UserCustomActions |
            Where-Object { $_.ClientSideComponentId -eq $componentId }
    )

    Write-Host ''
    Write-Host '=== MegaMenu Site-Scope-Test vorbereitet ===' -ForegroundColor Green
    Write-Host ('Site-Action-ID: ' + $siteAction.Id)
    Write-Host ('Component-ID: ' + $componentId)
    Write-Host ('Entfernte vorherige Site-Actions: ' + $removedSiteActions)
    Write-Host ('Entfernte Web-Actions: ' + $removedWebActions)
    Write-Host ('Verifizierte Site-Actions: ' + $verification.Count)
    Write-Host ('Properties: ' + $properties)
    Write-Host ''
    Write-Host 'Bitte jeweils mit Strg+F5 testen:' -ForegroundColor Cyan
    $testedWebUrls | ForEach-Object { Write-Host ('  ' + $_) }
    Write-Host ''
    Write-Host 'Rueckkehr zum bisherigen Web-Scope:' -ForegroundColor Yellow
    Write-Host ('.\deployment\add-megamenu.ps1 -SiteUrl ''' + $site.Url + '''')
}
finally {
    if ($site) {
        $site.Dispose()
    }
}