DSCResources/MSFT_xExchAntiMalwareScanning/MSFT_xExchAntiMalwareScanning.psm1

[Diagnostics.CodeAnalysis.SuppressMessageAttribute("PSDSCDscTestsPresent", "")]
[Diagnostics.CodeAnalysis.SuppressMessageAttribute("PSDSCDscExamplesPresent", "")]
[CmdletBinding()]
param()

function Get-TargetResource
{
    [Diagnostics.CodeAnalysis.SuppressMessageAttribute("PSDSCUseVerboseMessageInDSCResource", "")]
    [CmdletBinding()]
    [OutputType([System.Collections.Hashtable])]
    param
    (
        [parameter(Mandatory = $true)]
        [System.Boolean]
        $Enabled,

        [parameter(Mandatory = $true)]
        [System.Management.Automation.PSCredential]
        [System.Management.Automation.Credential()]
        $Credential,

        [System.Boolean]
        $AllowServiceRestart = $false
    )

    #Load helper module
    Import-Module "$((Get-Item -LiteralPath "$($PSScriptRoot)").Parent.Parent.FullName)\Misc\xExchangeCommon.psm1" -Verbose:0

    LogFunctionEntry -Parameters @{"Enabled" = $Enabled} -VerbosePreference $VerbosePreference

    #Establish remote Powershell session
    GetRemoteExchangeSession -Credential $Credential -CommandsToLoad 'Get-TransportAgent' -VerbosePreference $VerbosePreference

    $agent = Get-TransportAgent -Identity "Malware Agent"

    if ($null -ne $agent)
    {
        $returnValue = @{
            Enabled = $agent.Enabled
        }
    }

    $returnValue
}

function Set-TargetResource
{
    [Diagnostics.CodeAnalysis.SuppressMessageAttribute("PSDSCUseVerboseMessageInDSCResource", "")]
    [CmdletBinding()]
    param
    (
        [parameter(Mandatory = $true)]
        [System.Boolean]
        $Enabled,

        [parameter(Mandatory = $true)]
        [System.Management.Automation.PSCredential]
        [System.Management.Automation.Credential()]
        $Credential,

        [System.Boolean]
        $AllowServiceRestart = $false
    )

    #Load helper module
    Import-Module "$((Get-Item -LiteralPath "$($PSScriptRoot)").Parent.Parent.FullName)\Misc\xExchangeCommon.psm1" -Verbose:0

    LogFunctionEntry -Parameters @{"Enabled" = $Enabled} -VerbosePreference $VerbosePreference

    $scriptsRoot = Join-Path -Path ((Get-ItemProperty HKLM:\SOFTWARE\Microsoft\ExchangeServer\v15\Setup).MsiInstallPath) -ChildPath "Scripts"
    

    if ($Enabled -eq $true)
    {
        $scriptPath = Join-Path -Path "$($scriptsRoot)" -ChildPath "Enable-AntimalwareScanning.ps1"
    }
    else
    {
        $scriptPath = Join-Path -Path "$($scriptsRoot)" -ChildPath "Disable-AntimalwareScanning.ps1"
    }

    #Override Write-Host, as it is used by the target scripts, and causes a DSC error since the session is not interactive
    New-Alias Write-Host Write-Verbose

    if($AllowServiceRestart -eq $true)
    {
        . $scriptPath -ForceRestart
    }
    else
    {
        . $scriptPath

        Write-Warning "The configuration will not take effect until the MSExchangeTransport service is manually restarted."
    }

    Remove-Item Alias:Write-Host
}


function Test-TargetResource
{
    [Diagnostics.CodeAnalysis.SuppressMessageAttribute("PSDSCUseVerboseMessageInDSCResource", "")]
    [CmdletBinding()]
    [OutputType([System.Boolean])]
    param
    (
        [parameter(Mandatory = $true)]
        [System.Boolean]
        $Enabled,

        [parameter(Mandatory = $true)]
        [System.Management.Automation.PSCredential]
        [System.Management.Automation.Credential()]
        $Credential,

        [System.Boolean]
        $AllowServiceRestart = $false
    )

    #Load helper module
    Import-Module "$((Get-Item -LiteralPath "$($PSScriptRoot)").Parent.Parent.FullName)\Misc\xExchangeCommon.psm1" -Verbose:0
        
    LogFunctionEntry -Parameters @{"Enabled" = $Enabled} -VerbosePreference $VerbosePreference

    $agentStatus = Get-TargetResource @PSBoundParameters

    if ($null -eq $agentStatus)
    {
        return $false
    }
    else
    {
        if (!(VerifySetting -Name "Enabled" -Type "Boolean" -ExpectedValue $Enabled -ActualValue $agentStatus.Enabled -PSBoundParametersIn $PSBoundParameters -VerbosePreference $VerbosePreference))
        {
            return $false
        }
    }

    #If the code made it this for all properties are in a desired state
    return $true
}

Export-ModuleMember -Function *-TargetResource