Public/Get-PAPlugin.ps1

function Get-PAPlugin {
    [CmdletBinding(DefaultParameterSetName='Basic')]
    param(
        [Parameter(ParameterSetName='Basic', Position=0)]
        [Parameter(ParameterSetName='Help', Position=0, Mandatory)]
        [Parameter(ParameterSetName='Guide', Position=0, Mandatory)]
        [Parameter(ParameterSetName='Params', Position=0, Mandatory)]
        [ValidateScript({Test-ValidPlugin $_ -ThrowOnFail})]
        [string]$Plugin,
        [Parameter(ParameterSetName='Help', Mandatory)]
        [switch]$Help,
        [Parameter(ParameterSetName='Guide', Mandatory)]
        [switch]$Guide,
        [Parameter(ParameterSetName='Params', Mandatory)]
        [switch]$Params
    )

    # return the list of plugin details if a specific plugin wasn't specified
    if ([String]::IsNullOrWhiteSpace($Plugin)) {
        $script:Plugins.Values | Sort-Object Name
        return
    }

    $pluginDetail = $script:Plugins.$Plugin

    if ('Basic' -eq $PSCmdlet.ParameterSetName) {
        # return specific plugin details
        return $pluginDetail
    }

    # dot source the plugin
    . $pluginDetail.Path

    # get a reference to the associated add command
    if ('dns-01' -eq $pluginDetail.ChallengeType) {
        $cmd = Get-Command Add-DnsTxt
    } else {
        $cmd = Get-Command Add-HttpChallenge
    }

    if ('Params' -eq $PSCmdlet.ParameterSetName) {

        # define the set of parameter names to ignore
        $ignoreParams = @('RecordName','TxtValue','Domain','Token','Body') + [Management.Automation.PSCmdlet]::CommonParameters +
            [Management.Automation.PSCmdlet]::OptionalCommonParameters

        # Now we want to make a flattened list of parameters that are tagged with
        # their associated parameter set data to enable our custom output formatting
        $paramFlatList = foreach ($set in $cmd.ParameterSets) {

            $setParams = $set.Parameters | Where-Object {
                $_.Name -notin $ignoreParams -and
                $true -notin $_.Attributes.ValueFromRemainingArguments
            }

            $setParams | ForEach-Object {

                $setName = $set.Name
                if ($setName -eq '__AllParameterSets') {
                    $setName = '(Default)'
                }

                [pscustomobject]@{
                    PSTypeName = 'PoshACME.PluginParameter'
                    Plugin = $Plugin
                    ParameterSet = $setName
                    IsDefault = $set.IsDefault
                    Parameter = $_.Name
                    ParameterType = $_.ParameterType
                    IsMandatory = $_.IsMandatory
                }
            }
        }
        return $paramFlatList
    }

    elseif ('Guide' -eq $PSCmdlet.ParameterSetName) {
        # Currently opening a browser this way only works on Windows, but we're
        # tracking this issue for potentially better cross-platform solutions in
        # the future.
        # https://github.com/PowerShell/PowerShell/issues/7201

        $url = "https://poshac.me/docs/v4/Plugins/$($pluginDetail.Name)/"

        try {
            # launch the browser to the guide
            Start-Process $url
        } catch {
            # just return the URL
            $url
        }
        return
    }

    elseif ('Help' -eq $PSCmdlet.ParameterSetName) {

        if ('dns-01' -eq $pluginDetail.ChallengeType) {
            Get-Help Add-DnsTxt
        } else {
            Get-Help Add-HttpChallenge
        }
        return
    }
}