if (Get-Module posh-nodejs) { return }

$NodeJsHome = "$HOME\Apps\nodejs"

$InitialNodePath = $env:Path.Split(";") | Where-Object { $_ -like "$NodeJsHome*" }

function CompleteNodeJsVersion {
    param($commandName, $parameterName, $wordToComplete,
        $commandAst, $fakeBoundParameters)

    Get-ChildItem -Directory $NodeJsHome
    | ForEach-Object { $_.Name.Split("-")[1].Substring(1) }
    | Where-Object { $_ -Like "$wordToComplete*" }
    | Sort-Object
}


function nvm {
    [CmdletBinding()]
    param(
        [Parameter(Mandatory = $true)]
        [ValidateSet("list", "activate", "deactivate")]
        $command,

        [Parameter(Mandatory = $false)]
        [ArgumentCompleter({ CompleteNodeJsVersion @args })]
        $version)
    switch ($command) {
        "list" {
            Get-ChildItem -Directory $NodeJsHome
            | ForEach-Object {
                $version = $_.Name.Split("-")[1].Substring(1)
                Write-Output "$version"
            }
        }

        "activate" {
            $path = "$NodeJsHome\node-v$version-win-x64"
            if (Test-Path "$path") {
                $paths = $env:Path.Split(";") | Where-Object { $_ -NotLike "$NodeJsHome*" }
                $paths += $path
                $env:Path = $paths | Join-String -Separator ";"
            }
            else {
                Write-Error "NodeJS version '${version}' not found."
            }
        }

        "deactivate" {
            $paths = $env:Path.Split(";") | Where-Object { $_ -NotLike "$NodeJsHome*" }
            $paths += $InitialNodePath
            $env:Path = $paths | Join-String -Separator ";"
        }

        default {
            Write-Error "Unknown nvm command ${args[0]}."
        }
    }
}