licenses.ps1

function Update-MtLicenseCache {
    [OutputType([System.Void])]
    [CmdletBinding(
        SupportsShouldProcess,
        ConfirmImpact = "Low"
    )]

    param (
        [Switch]$Force,
        [String]$FileName="maesterLicenses.csv"
    )

    process {
        if ($Force -and -not $Confirm){
            $ConfirmPreference = "None"
        }

        try{
            Write-Verbose "Attempting License Cache Update"
            $csv = Invoke-RestMethod -Uri "https://download.microsoft.com/download/e/3/e/e3e9faf2-f28b-490a-9ada-c6089a1fc5b0/Product%20names%20and%20service%20plan%20identifiers%20for%20licensing.csv"
        }
        catch{
            Write-Error $_
            exit
        }
        Write-Verbose "Getting hash of downloaded content"
        $hashNew = Get-FileHash -InputStream ([IO.MemoryStream]::new([text.encoding]::UTF8.GetBytes($csv))) -Algorithm SHA256

        if(Test-Path -Path $env:TEMP\$FileName){
            Write-Verbose "Cache exists"
            $skus = Get-Content $env:TEMP\$FileName
            Write-Verbose "Getting cache hash"
            $hashOld = Get-FileHash -InputStream ([IO.MemoryStream]::new([text.encoding]::UTF8.GetBytes($skus))) -Algorithm SHA256
            if($hashNew.Hash -ne $hashOld.Hash -and $PSCmdlet.ShouldProcess($FileName)){
                Write-Verbose "Cache does not match download, overwriting"
                $csv|Out-File $env:TEMP\$FileName -Confirm:$false
                $skus = $csv|ConvertFrom-Csv
            }else{
                Write-Verbose "Cache matches"
                $skus = $skus|ConvertFrom-Csv
            }
        }else{
            Write-Verbose "Cache does not exist, setting cache"
            if($PSCmdlet.ShouldProcess($FileName)){
                $csv|Out-File $env:TEMP\$FileName -Confirm:$false
            }
            $skus = $csv|ConvertFrom-Csv
        }

        Write-Verbose "$(($skus|Measure-Object).Count) SKUs in cache"
        return $null
    }
}

function Get-MtLicenseRelationship {
    [OutputType([pscustomobject])]
    [CmdletBinding()]
    param (
        [Parameter(Mandatory, ParameterSetName = "regex")]
        [regex]$regexSearchString,
        [Parameter(Mandatory, ParameterSetName = "id")]
        [guid]$servicePlanId,
        [Parameter(Mandatory, ParameterSetName = "name")]
        [string]$servicePlanName,
        [Parameter(Mandatory, ParameterSetName = "sku")]
        [guid]$skuId,
        [Parameter(Mandatory, ParameterSetName = "pn")]
        [string]$skuPartNumber
    )

    process {
        if(-not (Test-Path $env:TEMP\maesterLicenses.csv)){
            Write-Verbose "License cache not found, updating"
            Update-MtLicenseCache
        }

        $plans = Import-Csv -Path $env:TEMP\maesterLicenses.csv

        $relationships = @()

        if($skuId){
            Write-Verbose "Processing as skuId"
            $relationships = $plans | Where-Object {`
                $_.GUID -eq $skuId
            }
        }elseif($servicePlanId){
            Write-Verbose "Processing as servicePlanId"
            $relationships = $plans | Where-Object {`
                $_.Service_Plan_Id -eq $servicePlanId
            }
        }elseif($servicePlanName){
            Write-Verbose "Processing as servicePlanName"
            $relationships = $plans | Where-Object {`
                $_.String_Id -eq $servicePlanName -or `
                $_.Service_Plan_Name -eq $servicePlanName
            }
        }elseif($skuPartNumber){
            Write-Verbose "Processing as skuPartNumber"
            $relationships = $plans | Where-Object {`
                $_.String_Id -eq $skuPartNumber -or `
                $_.Service_Plan_Name -eq $skuPartNumber
            }
        }elseif($regexSearchString){
            Write-Verbose "Processing as regexSearchString"
            foreach($plan in $plans){
                $match = $regexSearchString.Match($plan.Product_Display_Name).Success -or `
                    $regexSearchString.Match($plan.String_Id).Success -or `
                    $regexSearchString.Match($plan.Service_Plan_Name).Success -or `
                    $regexSearchString.Match($plan.Service_Plans_Included_Friendly_Names).Success

                if($match){
                    $relationships += $plan
                }
            }
        }

        return $relationships
    }
}