functions/grouppolicies/Invoke-DMGroupPolicy.ps1

function Invoke-DMGroupPolicy
{
    <#
    .SYNOPSIS
        Brings the group policy settings into compliance with the desired state.
     
    .DESCRIPTION
        Brings the group policy settings into compliance with the desired state.
        Define the desired state by using Register-DMGroupPolicy.
        Note: The original export will need to be carefully crafted to fit this system.
        TODO: Add definition on how to provide the GPO export,
     
    .PARAMETER Delete
        By default, this command will NOT delete group policies, in order to avoid accidentally locking yourself out of the system.
        Use this parameter to delete group policies that are no longer needed.
     
    .PARAMETER Server
        The server / domain to work with.
     
    .PARAMETER Credential
        The credentials to use for this operation.
     
    .PARAMETER EnableException
        This parameters disables user-friendly warnings and enables the throwing of exceptions.
        This is less user friendly, but allows catching exceptions in calling scripts.
 
    .PARAMETER Confirm
        If this switch is enabled, you will be prompted for confirmation before executing any operations that change state.
     
    .PARAMETER WhatIf
        If this switch is enabled, no actions are performed but informational messages will be displayed that explain what would happen if the command were to run.
     
    .EXAMPLE
        PS C:\> Invoke-DMGroupPolicy -Server fabrikam.com
 
        Brings the group policy settings from the domain fabrikam.com into compliance with the desired state.
 
    .EXAMPLE
        PS C:\> Invoke-DMGroupPolicy -Server fabrikam.com -Delete
 
        Brings the group policy settings from the domain fabrikam.com into compliance with the desired state.
        Will also delete all deprecated policies linked to the managed infrastructure.
    #>

    [CmdletBinding(SupportsShouldProcess = $true, ConfirmImpact = 'Medium')]
    param (
        [switch]
        $Delete,

        [PSFComputer]
        $Server,
        
        [PSCredential]
        $Credential,

        [switch]
        $EnableException
    )
    
    begin
    {
        $parameters = $PSBoundParameters | ConvertTo-PSFHashtable -Include Server, Credential
        $parameters['Debug'] = $false
        Assert-ADConnection @parameters -Cmdlet $PSCmdlet
        Invoke-Callback @parameters -Cmdlet $PSCmdlet
        Assert-Configuration -Type GroupPolicyObjects -Cmdlet $PSCmdlet
        $computerName = (Get-ADDomain @parameters).PDCEmulator
        $psParameter = $PSBoundParameters | ConvertTo-PSFHashtable -Include ComputerName, Credential -Inherit
        try { $session = New-PSSession @psParameter -ErrorAction Stop }
        catch {
            Stop-PSFFunction -String 'Invoke-DMGroupPolicy.WinRM.Failed' -StringValues $computerName -ErrorRecord $_ -EnableException $EnableException -Cmdlet $PSCmdlet -Target $computerName
            return
        }
        $PSDefaultParameterValues['Invoke-Command:Session'] = $session
        $testResult = Test-DMGroupPolicy @parameters
        Set-DMDomainContext @parameters

        if (-not $testResult) { return }

        try { $gpoRemotePath = New-GpoWorkingDirectory -Session $session -ErrorAction Stop }
        catch {
            Stop-PSFFunction -String 'Invoke-DMGroupPolicy.Remote.WorkingDirectory.Failed' -StringValues $computerName -Target $computerName -ErrorRecord $_ -EnableException $EnableException
            return
        }
    }
    process
    {
        if (Test-PSFFunctionInterrupt) { return }
        
        foreach ($testItem in $testResult) {
            switch ($testItem.Type) {
                'Delete' {
                    if (-not $Delete) { continue }
                    Invoke-PSFProtectedCommand -ActionString 'Invoke-DMGroupPolicy.Delete' -Target $testItem -ScriptBlock {
                        Remove-GroupPolicy -Session $session -ADObject $testItem.ADObject -ErrorAction Stop
                    } -EnableException $EnableException.ToBool() -PSCmdlet $PSCmdlet -Continue
                }
                'ConfigError' {
                    Invoke-PSFProtectedCommand -ActionString 'Invoke-DMGroupPolicy.Install.OnConfigError' -Target $testItem -ScriptBlock {
                        Install-GroupPolicy -Session $session -Configuration $testItem.Configuration -WorkingDirectory $gpoRemotePath -ErrorAction Stop
                    } -EnableException $EnableException.ToBool() -PSCmdlet $PSCmdlet -Continue
                }
                'CriticalError' {
                    Write-PSFMessage -Level Warning -String 'Invoke-DMGroupPolicy.Skipping.InCriticalState' -StringValues $testItem.Identity -Target $testItem
                }
                'Update' {
                    Invoke-PSFProtectedCommand -ActionString 'Invoke-DMGroupPolicy.Install.OnUpdate' -Target $testItem -ScriptBlock {
                        Install-GroupPolicy -Session $session -Configuration $testItem.Configuration -WorkingDirectory $gpoRemotePath -ErrorAction Stop
                    } -EnableException $EnableException.ToBool() -PSCmdlet $PSCmdlet -Continue
                }
                'Modified' {
                    Invoke-PSFProtectedCommand -ActionString 'Invoke-DMGroupPolicy.Install.OnModify' -Target $testItem -ScriptBlock {
                        Install-GroupPolicy -Session $session -Configuration $testItem.Configuration -WorkingDirectory $gpoRemotePath -ErrorAction Stop
                    } -EnableException $EnableException.ToBool() -PSCmdlet $PSCmdlet -Continue
                }
                'Manage' {
                    Invoke-PSFProtectedCommand -ActionString 'Invoke-DMGroupPolicy.Install.OnManage' -Target $testItem -ScriptBlock {
                        Install-GroupPolicy -Session $session -Configuration $testItem.Configuration -WorkingDirectory $gpoRemotePath -ErrorAction Stop
                    } -EnableException $EnableException.ToBool() -PSCmdlet $PSCmdlet -Continue
                }
                'Create' {
                    Invoke-PSFProtectedCommand -ActionString 'Invoke-DMGroupPolicy.Install.OnNew' -Target $testItem -ScriptBlock {
                        Install-GroupPolicy -Session $session -Configuration $testItem.Configuration -WorkingDirectory $gpoRemotePath -ErrorAction Stop
                    } -EnableException $EnableException.ToBool() -PSCmdlet $PSCmdlet -Continue
                }
            }
        }
    }
    end
    {
        if ($gpoRemotePath) {
            Invoke-Command -Session $session -ArgumentList $gpoRemotePath -ScriptBlock {
                param ($GpoRemotePath)
                Remove-Item -Path $GpoRemotePath -Recurse -Force -Confirm:$false -ErrorAction SilentlyContinue -WhatIf:$false
            }
        }
    }
}