DSCResources/MSFT_TeamsPstnUsage/MSFT_TeamsPstnUsage.psm1

function Get-TargetResource
{
    [CmdletBinding()]
    [OutputType([System.Collections.Hashtable])]
    param
    (
        [Parameter(Mandatory = $true)]
        [System.String]
        $Usage,

        [Parameter()]
        [ValidateSet('Present', 'Absent')]
        [System.String]
        $Ensure = 'Present',

        [Parameter(Mandatory = $true)]
        [System.Management.Automation.PSCredential]
        $GlobalAdminAccount
    )

    Write-Verbose -Message 'Getting Global PSTN Usage(s)'

    #region Telemetry
    $data = [System.Collections.Generic.Dictionary[[String], [String]]]::new()
    $data.Add('Resource', $MyInvocation.MyCommand.ModuleName)
    $data.Add('Method', $MyInvocation.MyCommand)
    $data.Add("Principal", $GlobalAdminAccount.UserName)
    Add-M365DSCTelemetryEvent  -Data $data
    #endregion

    $ConnectionMode = New-M365DSCConnection -Platform 'SkypeForBusiness' `
        -InboundParameters $PSBoundParameters

    $nullReturn = $PSBoundParameters
    $nullReturn.Ensure = "Absent"

    try
    {
        $deployedUsages = Get-CsOnlinePstnUsage -ErrorAction Stop | Select-Object -ExpandProperty Usage

        if ($deployedUsages -match $Usage)
        {
            $foundUsage = $Usage
        }
        else
        {
            $foundUsage = $null
        }

        if ($null -eq $foundUsage)
        {
            Write-Verbose -Message "Could not find PSTN usage {$Usage}"
            return $nullReturn
        }
        Write-Verbose -Message "Found PSTN usage {$Usage}"
        return @{
            Usage              = $Usage
            Ensure             = 'Present'
            GlobalAdminAccount = $GlobalAdminAccount
        }
    }
    catch
    {
        Write-Verbose -Message $_
        Add-M365DSCEvent -Message $_ -EntryType 'Error' `
            -EventID 1 -Source $($MyInvocation.MyCommand.Source)
        return $nullReturn
    }
}

function Set-TargetResource
{
    [CmdletBinding()]
    param
    (
        [Parameter(Mandatory = $true)]
        [System.String]
        $Usage,

        [Parameter()]
        [ValidateSet('Present', 'Absent')]
        [System.String]
        $Ensure = 'Present',

        [Parameter(Mandatory = $true)]
        [System.Management.Automation.PSCredential]
        $GlobalAdminAccount
    )

    Write-Verbose -Message 'Setting PSTN Usage'

    #region Telemetry
    $data = [System.Collections.Generic.Dictionary[[String], [String]]]::new()
    $data.Add('Resource', $MyInvocation.MyCommand.ModuleName)
    $data.Add('Method', $MyInvocation.MyCommand)
    $data.Add("Principal", $GlobalAdminAccount.UserName)
    Add-M365DSCTelemetryEvent -Data $data
    #endregion

    $ConnectionMode = New-M365DSCConnection -Platform 'SkypeForBusiness' `
        -InboundParameters $PSBoundParameters

    $CurrentValues = Get-TargetResource @PSBoundParameters

    $SetParameters = $PSBoundParameters
    $SetParameters.Remove('Ensure') | Out-Null
    $SetParameters.Remove('GlobalAdminAccount') | Out-Null

    if ($Ensure -eq 'Present' -and $CurrentValues.Ensure -eq 'Absent')
    {
        Write-Verbose -Message "Creating a new PSTN usage {$Usage}"
        Set-CsOnlinePstnUsage -Usage @{ add = $Usage }
    }
    elseif ($Ensure -eq 'Absent' -and $CurrentValues.Ensure -eq 'Present')
    {
        Write-Verbose -Message "Removing existing PSTN usage {$Usage}"
        Set-CsOnlinePstnUsage -Usage @{ remove = $Usage }
    }
}

function Test-TargetResource
{
    [CmdletBinding()]
    [OutputType([System.Boolean])]
    param
    (
        [Parameter(Mandatory = $true)]
        [System.String]
        $Usage,

        [Parameter()]
        [ValidateSet('Present', 'Absent')]
        [System.String]
        $Ensure = 'Present',

        [Parameter(Mandatory = $true)]
        [System.Management.Automation.PSCredential]
        $GlobalAdminAccount
    )

    Write-Verbose -Message "Testing configuration of PSTN Usage {$Usage}"

    $CurrentValues = Get-TargetResource @PSBoundParameters

    Write-Verbose -Message "Current Values: $(Convert-M365DscHashtableToString -Hashtable $CurrentValues)"
    Write-Verbose -Message "Target Values: $(Convert-M365DscHashtableToString -Hashtable $PSBoundParameters)"

    $ValuesToCheck = $PSBoundParameters
    $ValuesToCheck.Remove('GlobalAdminAccount') | Out-Null

    $TestResult = Test-M365DSCParameterState -CurrentValues $CurrentValues `
        -Source $($MyInvocation.MyCommand.Source) `
        -DesiredValues $PSBoundParameters `
        -ValuesToCheck $ValuesToCheck.Keys

    Write-Verbose -Message "Test-TargetResource returned $TestResult"

    return $TestResult
}

function Export-TargetResource
{
    [CmdletBinding()]
    [OutputType([System.String])]
    param
    (
        [Parameter(Mandatory = $true)]
        [System.Management.Automation.PSCredential]
        $GlobalAdminAccount
    )
    #region Telemetry
    $data = [System.Collections.Generic.Dictionary[[String], [String]]]::new()
    $data.Add('Resource', $MyInvocation.MyCommand.ModuleName)
    $data.Add('Method', $MyInvocation.MyCommand)
    $data.Add("Principal", $GlobalAdminAccount.UserName)
    Add-M365DSCTelemetryEvent -Data $data
    #endregion

    $ConnectionMode = New-M365DSCConnection -Platform 'SkypeForBusiness' `
        -InboundParameters $PSBoundParameters

    try
    {
        $i = 1
        [array]$usages = Get-CsOnlinePstnUsage -ErrorAction Stop | Select-Object -ExpandProperty Usage
        $content = ''
        Write-Host "`r`n" -NoNewLine
        foreach ($usage in $usages)
        {
            Write-Host " |---[$i/$($usages.Count)] $usage" -NoNewLine
            $params = @{
                Usage              = $usage
                Ensure             = 'Present'
                GlobalAdminAccount = $GlobalAdminAccount
            }
            $result = Get-TargetResource @params
            $result.GlobalAdminAccount = Resolve-Credentials -UserName 'globaladmin'
            $content += " TeamsPstnUsage " + (New-GUID).ToString() + "`r`n"
            $content += " {`r`n"
            $currentDSCBlock = Get-DSCBlock -Params $result -ModulePath $PSScriptRoot
            $content += Convert-DSCStringParamToVariable -DSCBlock $currentDSCBlock -ParameterName 'GlobalAdminAccount'
            $content += " }`r`n"
            $i++
            Write-Host $Global:M365DSCEmojiGreenCheckMark
        }
        return $content
    }
    catch
    {
        Write-Verbose -Message $_
        Add-M365DSCEvent -Message $_ -EntryType 'Error' `
            -EventID 1 -Source $($MyInvocation.MyCommand.Source)
        return ""
    }
}

Export-ModuleMember -Function *-TargetResource