param([switch]$IgnoreSystem,[switch]$MissingOnly)

$local:currentSys = @('Always') + ([SystemName]::_GetValidValues('',$true,$true));

$local:oldPSGet = Get-Module PowerShellGet -ListAvailable -ErrorAction SilentlyContinue |
    Sort-Object -Property Version -Descending |
    Select-Object -First 1 |
    Where-Object { $_.Version.Major -eq 1 }
if( $local:oldPSGet ) {
    Write-Warning $(@(
          "PowerShellGet is an old version ($($oldPSGet.Version)), the following code should upgrade it"
        , "    [Net.ServicePointManager]::SecurityProtocol = [System.Net.SecurityProtocolType]::Tls12"
        , "    Install-PackageProvider -Name NuGet -Force"
        , "    Remove-Module PowerShellGet"
        , "    Install-Module -Name PowerShellGet -Force"
        , "    Update-Module -Name PowerShellGet"
    ) -join "`n" )
}

[MyConfig]::GetConfigPaths('mymodules',$false) |
    ForEach-Object { 
        $local:modules = $( Get-Content $_ | ConvertFrom-Json );
        $modules |
            Get-Member -MemberType NoteProperty | Select-Object -ExpandProperty Name |
            Where-Object {
                $IgnoreSystem -or ( $_ -in $currentSys )
            } |
            ForEach-Object { $modules."$_" }
    } |
    Where-Object {
        -not $MissingOnly -or
        $( try  {
            -not (Get-Module -ListAvailable $_ -ErrorAction stop)
            } catch { $true }
        )
    }