#requires -Version 3.0 -Modules UpdateServices

<#
   .SYNOPSIS
   Approves all Windows Server Update Services (WSUS) definition updates

   .DESCRIPTION
   Approves all definition updates to all given Windows Server Update Services (WSUS) Computer Groups

   .PARAMETER Name
   Specifies the name of a WSUS server.

   .PARAMETER TargetGroupNames
   Specifies the name(s) of the WSUS computer target group(s) for which to run this cmdlet.

   .EXAMPLE
   PS C:\> Approve-WSUSDefinitionUpdates -TargetGroupNames 'All Computers'

   Approve Definition Updates to the 'All Computers' Group

   .EXAMPLE
   PS C:\> Approve-WSUSDefinitionUpdates -Name 'mycdc01' -TargetGroupNames 'All Computers'

   Approves all definition updates to the 'All Computers' Group on the Windows Server Update Services (WSUS) Server 'mycdc01'

   .EXAMPLE
   PS C:\> Approve-WSUSDefinitionUpdates -TargetGroupNames 'All Computers' -WhatfIf

   Simmulate the approval of all definition updates to the 'All Computers' Windows Server Update Services (WSUS) Group

   .EXAMPLE
   PS C:\> Approve-WSUSDefinitionUpdates -TargetGroupNames 'Pilot Servers','Pilot Workstations'

   Approves all definition updates to the 'Pilot Servers' and 'Pilot Workstations' Windows Server Update Services (WSUS) groups

   .NOTES
   Initial beta Version
#>
[CmdletBinding(ConfirmImpact = 'Low',
   SupportsShouldProcess)]
param
(
   [Parameter(ValueFromPipeline,
      ValueFromPipelineByPropertyName,
      Position = 1)]
   [Alias('WSUSServer')]
   [string]
   $Name = $null,
   [Parameter(Mandatory,
      ValueFromPipeline,
      ValueFromPipelineByPropertyName,
      Position = 2,
      HelpMessage = 'Specifies the name(s) of the WSUS computer target group(s) for which to run this cmdlet.')]
   [ValidateNotNullOrEmpty()]
   [Alias('InstallGroups')]
   [string[]]
   $TargetGroupNames
)

begin
{
   try
   {
      # Set the Defaults
      $paramGetWsusServer = @{
         ErrorAction   = 'Stop'
         WarningAction = 'Continue'
      }

      if ($Name)
      {
         Write-Verbose -Message ('Use {0} as WSUS Server' -f $Name)

         # Add the Name field with the given value to the Hashtable (Command Splat)
         $paramGetWsusServer['Name'] = $Name
      }

      $WSUS = (Get-WsusServer @paramGetWsusServer)
   }
   catch
   {
      # Get error record
      [Management.Automation.ErrorRecord]$e = $_

      # Retrieve information about the error
      $info = [PSCustomObject]@{
         Exception = $e.Exception.Message
         Reason    = $e.CategoryInfo.Reason
         Target    = $e.CategoryInfo.TargetName
         Script    = $e.InvocationInfo.ScriptName
         Line      = $e.InvocationInfo.ScriptLineNumber
         Column    = $e.InvocationInfo.OffsetInLine
      }

      # Do some verbose stuff for troubleshooting
      $info | Out-String | Write-Verbose

      # Thow the error and go...
      Write-Error -Message "$info.Exception" -ErrorAction Stop

      # This is a point the code should never reach (You told PowerShell to Ignore the ErrorAction above!)
      break

      # OK, now we have reached a point the we would never, never ever, see
      exit 1
   }

   $DefinitionUpdates = $null
   $DefinitionUpdates = $WSUS.GetUpdateClassifications() | Where-Object -FilterScript {
      $_.Title -eq 'Definition Updates'
   }

   if (-not $DefinitionUpdates)
   {
      Write-Error -Message 'No Definition Updates found!' -ErrorAction Stop

      break

      exit 1
   }

   $AllDefinitionUpdates = $null
   $AllDefinitionUpdates = $DefinitionUpdates.GetUpdates() | Where-Object -FilterScript {
      ($_.Title -like 'Definition Update for Microsoft Security Essentials*') -or ($_.Title -like 'Update for Windows Defender Antivirus antimalware platforms*') -or ($_.Title -like 'Definition Update for Windows Defender Antivirus*')
   }

   if (-not $AllDefinitionUpdates)
   {
      # Thow the error and go...
      Write-Error -Message 'No Definition Updates found!!!' -ErrorAction Stop

      # This is a point the code should never reach (You told PowerShell to Ignore the ErrorAction above!)
      break

      # OK, now we have reached a point the we would never, never ever, see
      exit 1
   }

}

process
{
   # Loop over all Updates
   foreach ($UpdateID in $AllDefinitionUpdates.Id.UpdateId.Guid)
   {
      # Loop over all Goups
      foreach ($TargetGroupName in $TargetGroupNames)
      {
         try
         {
            $paramGetWsusUpdate = @{
               UpdateId      = $UpdateID
               ErrorAction   = 'Stop'
               WarningAction = 'SilentlyContinue'
            }
            $paramApproveWsusUpdate = @{
               Action          = 'Install'
               TargetGroupName = $TargetGroupName
               ErrorAction     = 'Stop'
               WarningAction   = 'SilentlyContinue'
            }
            if ($pscmdlet.ShouldProcess("$UpdateID to $TargetGroupName", 'Approve'))
            {
               $null = (Get-WsusUpdate @paramGetWsusUpdate | Approve-WsusUpdate @paramApproveWsusUpdate)
            }
         }
         catch
         {
            # Get error record
            [Management.Automation.ErrorRecord]$e = $_

            # Retrieve information about the error
            $info = [PSCustomObject]@{
               Exception = $e.Exception.Message
               Reason    = $e.CategoryInfo.Reason
               Target    = $e.CategoryInfo.TargetName
               Script    = $e.InvocationInfo.ScriptName
               Line      = $e.InvocationInfo.ScriptLineNumber
               Column    = $e.InvocationInfo.OffsetInLine
            }

            # Do some verbose stuff for troubleshooting
            $info | Out-String | Write-Verbose

            # A simple warning is OK here
            Write-Warning -Message "$info.Exception" -WarningAction Continue -ErrorAction Continue
         }
      }
   }
}

end
{
   Write-Verbose -Message 'Done'
}

#region LICENSE
<#
   BSD 3-Clause License

   Copyright (c) 2021, enabling Technology
   All rights reserved.

   Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:

   1. Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.
   2. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution.
   3. Neither the name of the copyright holder nor the names of its contributors may be used to endorse or promote products derived from this software without specific prior written permission.

   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
#>
#endregion LICENSE

#region DISCLAIMER
<#
   DISCLAIMER:
   - Use at your own risk, etc.
   - This is open-source software, if you find an issue try to fix it yourself. There is no support and/or warranty in any kind
   - This is a third-party Software
   - The developer of this Software is NOT sponsored by or affiliated with Microsoft Corp (MSFT) or any of its subsidiaries in any way
   - The Software is not supported by Microsoft Corp (MSFT)
   - By using the Software, you agree to the License, Terms, and any Conditions declared and described above
   - If you disagree with any of the terms, and any conditions declared: Just delete it and build your own solution
#>
#endregion DISCLAIMER